JP2002086932A - Thermally reversible recording medium, card, disk cartridge, disk tape cassette and label and image processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermally reversible recording medium which widens the range of a temperature for transparency, enables attainment of sufficient image erasability and a high contrast even when an environmental temperature changes, and enables attainment of sufficient opacity even when it is stored in the presence of a basic substance. SOLUTION: In the thermally reversible recording medium which is constituted mainly of a resin matrix and an organic low-molecular substance dispersed in the resin matrix and of which the transparency changes reversibly dependently on temperature, at least one kind of linear-chain hydrocarbon containing compound (A) having a bond selected from the following (1) a urethane bond (2), a sulfonyl bond, (3) a diamide oxalate bond, (4) a diacyl hydrazide bond, (5) a urea bond and the urethane bond, (6) the urea bond and an amide bond and (7) a plurality of urea bonds and not having a carboxyl group and at least one kind of linear chain hydrocarbon containing compound (B) of which the melting point is lower by not less than 20 deg.C than that of the compound (A) are used by mixture as the organic low-molecular substance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoreversible recording medium, a card, and a disk cartridge which can repeatedly form and erase an image by using a reversible change in transparency of a heat-sensitive layer depending on the temperature. , Disk, tape cassette, label and image processing method.

[0002]

2. Description of the Related Art In recent years, a thermoreversible recording medium having a heat-sensitive layer, in which a temporary image can be displayed, the image can be erased when it becomes unnecessary, and the transparency reversibly changes depending on the temperature, has attracted attention. ing. A typical example is a thermoreversible recording medium in which an organic low-molecular substance such as a higher fatty acid is dispersed in a resin base material such as a vinyl chloride-vinyl acetate copolymer described in JP-A-55-154198. Are known. However, these conventional thermoreversible recording media have the drawback that the range of the temperature range showing light transmission and transparency is as narrow as 2 to 4 ° C., and an image is formed using light transmission / transparency and light shielding / white turbidity. It was difficult to control the temperature during formation.

[0003] As a method of expanding the transparentization temperature range, JP-A-2-1363, JP-A-3-2089,
JP-A-4-366682, JP-A-6-25524
As described in Japanese Patent Publication No. 7, a mixture of a higher fatty acid, a higher ketone or a fatty acid ester and an aliphatic dicarboxylic acid has been proposed. By these methods,
The temperature range in which the image becomes transparent could be expanded, and the erasing (transparency) of the image became easy.

Incidentally, these thermoreversible recording media are often used for applications such as point cards. Because loyalty cards are used repeatedly over a long period of time,
It will be stored under various conditions. If the card is stored in an environment where a trace amount of a basic substance such as ammonia or amine is stored, a cloudy image cannot be formed even at a very low concentration of such a substance. Was. It is believed that the reason why the cloudy image cannot be formed is that the carboxyl group of the low-molecular substance and the basic substance form a salt and raise the melting point of the low-molecular substance.

Further, Japanese Patent Application Laid-Open No. H5-294062 proposes to use a mixture of a higher ketone or a fatty acid ester and a saturated aliphatic bisamide to widen the temperature range for clearing. These do not use a low-molecular substance having a carboxyl group, so that the influence of the basic substance is small, and although the range of the clearing temperature is slightly widened and the erasability is improved,
There is a disadvantage that the contrast is low.

Further, Japanese Patent Application Laid-Open No. 11-58988 discloses the use of a low-melting low-molecular substance such as a fatty acid ester, a fatty acid metal salt such as copper stearate, or a fatty acid amide in order to reduce the influence of a basic substance. Has been proposed. However, these have the drawback that, although the effect of the basic substance is reduced, when copper stearate is used, since the material is colored blue, the medium is also colored blue. When the amide was used, the melting point of the amide was not so high, so that there was a drawback that the clearing temperature range was narrow and it was difficult to erase (clear) the image.

[0007]

SUMMARY OF THE INVENTION In view of such circumstances, the present invention broadens the temperature range of transparency and provides sufficient image erasability and high contrast even when the environmental temperature changes.
And thermoreversible recording media, cards, disk cartridges, disks, tape cassettes and labels that provide sufficient turbidity even when stored in the presence of a basic substance, and image processing methods for image formation and erasing using the same Is to provide

[0008]

Means for Solving the Problems As described above, the object of the present invention is to provide [1] a resin base material and an organic low-molecular substance dispersed in the resin base material as main components, and the transparency depends on the temperature. In a thermoreversible recording medium having a reversibly changing thermosensitive layer,
As the organic low molecular weight substance, at least one kind of the compound (A) containing a straight-chain hydrocarbon having no carboxyl group and the compound (A) selected from the following (1) to (7): (1) a thermoreversible recording medium characterized by using a mixture of at least one kind of a linear hydrocarbon-containing compound (B) having no carboxyl group having a melting point lower by at least 20 ° C. than the melting point of (2) Linear hydrocarbon-containing compound having a sulfonyl bond (3) Linear hydrocarbon-containing compound having an oxalic acid diamide bond (4) Linear hydrocarbon-containing compound having a diacylhydrazide bond (5) Linear hydrocarbon-containing compound having a urea bond and a urethane bond (6) Linear hydrocarbon-containing compound having a urea bond and an amide bond (7) A straight chain having a plurality of urea bonds Linear hydrocarbon-containing compound [2] Melting point of linear hydrocarbon-containing compound (A) is 100 ° C.
The thermoreversible recording medium according to the above [1], wherein the linear hydrocarbon-containing compound (B) has a melting point of 50 ° C. or more and less than 100 ° C. The thermoreversible recording medium according to the above [1] or [2],
[4] The compound of the above [1] to [3], wherein the mixing ratio of the linear hydrocarbon-containing compound (A) and the linear hydrocarbon-containing compound (B) is 80:20 to 1:99. The thermoreversible recording medium according to any one of [5], wherein the linear hydrocarbon-containing compound (B) is a fatty acid ester, a ketone having a higher alkyl group, a dibasic acid ester, a polyhydric alcohol difatty acid ester, or an aliphatic monoamide compound. A thermoreversible recording medium according to any one of the above [1] to [4], which is at least one selected from aliphatic monourea compounds, [6] satisfying the following three conditions: The thermoreversible recording medium according to any one of the above [1] to [5], wherein (a) the upper limit temperature of transparency is 115 ° C. or higher, and (b) the temperature difference between the upper limit temperature of transparency and the lower limit temperature of cloudiness. Is 20
° C or less (c) Transparency temperature range is 30 ° C or more [7] The gel fraction value of the resin base material is 30% or more, any one of the above-mentioned [1] to [6]. A thermoreversible recording medium, [8] wherein at least a part of the resin base material is cross-linked;
The thermoreversible recording medium according to any one of the above.

[0009] The object of the present invention is to provide a thermoreversible recording medium according to any one of [9] to [9] of the present invention, wherein the thermoreversible recording medium has an information storage section. A card, a disk, a disk cartridge or a tape cassette, [10] at least the thermoreversible recording medium according to any of the above [1] to [8]. This is achieved by a thermoreversible recording label comprising a thermoreversible recording section, a support, an adhesive layer or a pressure-sensitive adhesive layer, and laminated in this order.

[0010] Furthermore, the above object is achieved by the present invention [11].
Using the thermoreversible recording medium, card, disk, disk cartridge, tape cassette or label according to any one of the above [1] to [10], image recording and / or erasing is performed by heating. Image processing method,
[12] The image processing method according to [11], wherein an image is formed using a thermal head.
[13] The image processing method according to [11] or [12], wherein the image is erased using a thermal head or a ceramic heater.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The thermoreversible recording medium of the present invention utilizes the change in transparency (transparent state, cloudy opaque state) as described above. The difference between this transparent state and cloudy opaque state is presumed as follows. That is, (i) in the case of transparency, the particles of the organic low-molecular substance dispersed in the resin base material and the resin base material are in close contact with each other without any gap, and there is no void in the particle portion.
Light incident from one side is not scattered but is transmitted to the other side without being scattered, and it appears transparent. (Ii) In the case of cloudiness, fine particles of the organic low molecular substance are aggregated in the particles of the organic low molecular substance It is made of polycrystal, and there is a gap at the interface of the crystal or the interface between the particle and the resin base material, and the light incident from one side looks white because it is refracted, reflected, and scattered at the interface between the void and the crystal, and the interface between the void and the resin. , Etc.

FIG. 1 shows an example of the thermoreversible recording medium of the present invention.
Temperature-transparency change in the drawing to make it easy to understand,
In FIG. 1, the resin base material and the resin base material dispersed in the resin base material
The heat-sensitive layer mainly composed of an organic low-molecular substance is made of, for example, T₀
It is cloudy and opaque at the following room temperature. This is heating
Temperature T₁And gradually begin to become transparent, the temperature T_Two~ T _Three
, It becomes transparent when heated to T₀Always
It remains transparent when warmed. This is the temperature T₁Nearby
The resin begins to soften, and as the softening progresses, the resin
Interface or particles between resin and organic low-molecular substance particles that shrink
Transparency gradually rises to reduce voids inside,
Degree T_Two~ T_ThreeIn this case, the organic low-molecular-weight substance is in a semi-molten state,
Filled low-molecular-weight substances fill the voids
It becomes transparent and is cooled while the seed crystal remains.
Crystallizes at a relatively high temperature, and the resin is still softened
Resin follows the volume change of particles due to crystallization
Is considered to be due to the absence of voids and the maintenance of the transparent state.
available.

Further heating to a temperature above T ₄ results in a translucent state intermediate between the maximum transparency and the maximum opacity. Next, when the temperature is lowered, the state returns to the original cloudy and opaque state without taking the transparent state again. After this the organic low molecular weight substance at a temperature T ₄ or more completely melted, becomes a supercooled state, is crystallized at a temperature slightly higher than T _0, this time, can not follow the volume change of the resin is caused by the crystallization, the gap It seems to be caused. However, the temperature shown in FIG.
The transparency change curve is only a typical example, and the transparency of each state may change depending on the material by changing the material.

In the present invention, at least one kind of the linear hydrocarbon-containing compound (A) having no carboxyl group and a melting point lower than the melting point of the linear hydrocarbon-containing compound (A) by at least 20 ° C. A mixture of at least one of the linear hydrocarbon-containing compounds (B) having no carboxyl group is used.

Here, the linear hydrocarbon-containing compound (A)
Has a polar group in the molecule, and preferably has a methyl group at the terminal of the molecule. Examples of the polar group in the molecule include a urethane bond, a sulfonyl bond, an oxalic acid diamide bond (—NHCOCONH—), a diacylhydrazide bond (—CONHNHCO—), and a urea bond.

Specifically, the linear hydrocarbon-containing compound (A) has at least one of a urethane bond, a sulfonyl bond, an oxalic acid diamide bond (—NHCOCONH—), and a diacylhydrazide bond (—CONHNHCO—). Or a compound having at least one urethane bond or amide bond and a urea bond, or a compound having a plurality of urea bonds.

The straight-chain hydrocarbon contained in the straight-chain hydrocarbon-containing compound (A) preferably has 6 to 60 carbon atoms,
~ 50 is more preferable. Further, the linear hydrocarbon-containing compound (A) may have a phenylene or cyclohexylene structure, a cyclohexyl group, or a phenyl group in addition to the linear hydrocarbon.

The melting point of the linear hydrocarbon-containing compound (A) is
100 ° C. or higher is preferable, 110 ° C. or higher is more preferable, 120 ° C. or higher is further preferable, 130 ° C. or higher is particularly preferable, and 180 ° C. or lower is preferable, 160 ° C.
The following is more preferable, and 150 ° C. or lower is particularly preferable. If the melting point is too low, the clarifying temperature range cannot be expanded, and the erasability will be reduced. If the melting point is too high, the sensitivity in forming a cloudy image will be reduced.

Specific examples of the linear hydrocarbon-containing compound (A) will be given below, but it should not be construed that the invention is limited thereto.

[Table 1]

The alkyl group preferably has 1 to 30 carbon atoms, more preferably 3 to 26 carbon atoms, and particularly preferably 5 to 22 carbon atoms. Methylene preferably has 1 to 30 carbon atoms,
-26 are more preferable, and 5-22 are especially preferable. The total number of carbon atoms in the linear hydrocarbon chain including the alkyl group and methylene in the molecule is preferably 8 or more, more preferably 10 or more, particularly preferably 14 or more, and also preferably 60 or less, more preferably 50 or less. , 40 or less is particularly preferred. If the number of carbon atoms is too small, the compatibility with the resin is improved, and it becomes difficult to form low-molecular substance particles, which causes a problem that the contrast is reduced.If the number of carbon atoms is too large, the compatibility with the low-melting low-molecular substance is reduced. A problem arises in that the transparentization temperature range cannot be expanded.

Examples of the substance of the general formula (1) include the following. Melting point CH ₃ (CH ₂ ) ₁₁ OOCNH (CH ₂ ) ₆ NHCOO (CH ₂ ) ₁₁ CH ₃ 113 ℃ CH ₃ (CH ₂ ) ₁₇ OOCNH (CH ₂ ) ₆ NHCOO (CH ₂ ) ₁₇ CH ₃ 119 ℃ CH ₃ ( CH ₂ ) ₂₁ OOCNH (CH ₂ ) ₆ NHCOO (CH ₂ ) ₂₁ CH ₃ 121 ° C

Examples of the substance of the general formula (2) include the following. Melting point CH ₃ (CH ₂ ) ₁₇ NHCOO (CH ₂ ) ₂ OOCNH (CH ₂ ) ₁₇ CH ₃ 115 ℃ CH ₃ (CH ₂ ) ₁₇ NHCOO (CH ₂ ) ₄ OOCNH (CH ₂ ) ₁₇ CH ₃ 119 ℃ CH ₃ ( CH ₂ ) ₁₇ NHCOO (CH ₂ ) ₆ OOCNH (CH ₂ ) ₁₇ CH ₃ 111 ° C

Examples of the substance of the general formula (3) include the following. Melting point CH ₃ (CH ₂ ) ₁₁ NHCOCONH (CH ₂ ) ₁₁ CH ₃ 124 ° C CH ₃ (CH ₂ ) ₁₇ NHCOCONH (CH ₂ ) ₁₇ CH ₃ 121 ° C

Examples of the substance of the general formula (4) include the following. Melting point CH ₃ (CH ₂ ) ₁₀ CONHNHCO (CH ₂ ) ₁₀ CH ₃ 151 ° C CH ₃ (CH ₂ ) ₁₆ CONHNHCO (CH ₂ ) ₁₀ CH ₃ 134 ° C CH ₃ (CH ₂ ) ₁₆ CONHNHCO (CH ₂ ) ₁₆ CH ₃ 147 ℃ CH ₃ (CH ₂ ) ₂₀ CONHNHCO (CH ₂ ) ₁₆ CH ₃ 136 ℃ CH ₃ (CH ₂ ) ₂₀ CONHNHCO (CH ₂ ) ₂₀ CH ₃ 143 ℃

Examples of the substance of the general formula (5) include the following. Melting point CH ₃ (CH ₂ ) ₁₁ SO ₂ (CH ₂ ) ₄ SO ₂ (CH ₂ ) ₁₁ CH ₃ 149 ° C CH ₃ (CH ₂ ) ₁₇ SO ₂ (CH ₂ ) ₂ SO ₂ (CH ₂ ) ₁₇ CH ₃ 150 ℃ CH ₃ (CH ₂ ) ₁₇ SO ₂ (CH ₂ ) ₄ SO ₂ (CH ₂ ) ₁₇ CH ₃ 148 ℃

Examples of the substance of the general formula (6) include the following. Melting point CH ₃ (CH ₂ ) ₁₇ NHCO (CH ₂ ) ₄ NHCONH (CH ₂ ) ₁₇ CH ₃ 144 ° C

Examples of the substance of the general formula (7) include the following. Melting point CH ₃ (CH ₂ ) ₁₆ CONH (CH ₂ ) ₆ NHCONH (CH ₂ ) ₁₇ CH ₃ 149 ° C

Examples of the substance of the general formula (8) include the following. Melting point CH ₃ (CH ₂ ) ₁₇ NHCO (CH ₂ ) ₂ NHCONH (CH ₂ ) ₁₇ CH ₃ 127 ° C

Examples of the substance of the general formula (9) include the following. Melting point CH ₃ (CH ₂ ) ₁₇ NHCONH (CH ₂ ) ₆ NHCONH (CH ₂ ) ₁₇ CH ₃ 177 ° C

Examples of the substance of the general formula (10) include the following.

Embedded image

The following is an example of a method for synthesizing the above-mentioned linear hydrocarbon-containing compound (A). One example of the substance of the above general formula (1) is octadecyloxy-N- [6- (octadecyloxycarbonylamino) hexyl] carboxamide (CH ₃ (CH ₂ ) ₁₇ OOCNH (CH ₂ ) ₆ NHCOO (CH ₂ ) ₁₇ CH ₃ ) Is shown below, but is not limited thereto.

A solution of stearyl alcohol (20.1 g) and hexamethylene diisocyanate (5.1 g) in tetrahydrofuran (125.5 g) was stirred under reflux for 3 hours.
The precipitated crystals were separated by filtration and recrystallized from toluene to obtain 17.7 g of the desired compound.

One example of the substance of the above general formula (2) is N-octadecyl [4- (N-octadecylcarbonyloxy)
Butoxy] carboxamide (CH ₃ (CH ₂ ) ₁₇ NHCOO (CH ₂ ) ₄ OOC
An example of the synthesis of NH (CH ₂ ) ₁₇ CH ₃ ) is shown below, but is not limited thereto.

A tetrahydrofuran solution (103.0 g) of 2.6 g of 1,4-butanediol and 18.0 g of stearyl isocyanate was stirred under reflux for 5 hours. The precipitated crystals were separated by filtration and recrystallized from toluene to obtain 17.5 g of the desired compound.

The following is an example of the synthesis of N-octadecyl-N'-octadecylethane-1,2 diamide (CH ₃ (CH ₂ ) ₁₇ NHCOCONH (CH ₂ ) ₁₇ CH ₃ ), which is an example of the substance of the above general formula (3). However, the present invention is not limited to this.

A solution of 53.5 g of stearylamine and 15.7 g of pyridine in tetrahydrofuran (599.2 g)
At room temperature, a solution of oxalyl chloride (12.0 g) in tetrahydrofuran (120.0 g) was added dropwise. After the addition, the mixture was stirred at room temperature for 5 hours. The precipitated crystals were separated by filtration, washed with water, and recrystallized with toluene to give the desired compound.
6 g were obtained.

One example of the substance of the above general formula (4) is N- (octadecanoylamino) octadecaneamide (CH ₃ (CH ₂ )
An example of the synthesis of ₁₆ CONHNHCO (CH ₂ ) ₁₇ CH ₃ ) is shown below, but is not limited thereto.

A solution of 20.0 g of stearic hydrazide, 21.0 g of stearic acid and 10.3 g of 1-hydroxybenzotriazole in tetrahydrofuran (205.0)
To g), 9.3 g of diisopropylcarbodiimide was added dropwise at room temperature, and the mixture was stirred under reflux for 3 hours. The precipitated crystals were separated by filtration and recrystallized from isopropyl alcohol to obtain 23.9 g of the desired compound.

One example of the substance of the general formula (5) is 1,2-
Bis (octadecylsulfonyl) ethane (CH ₃ (CH ₂ ) ₁₇ SO
An example of the synthesis of ₂ (CH ₂ ) ₄ SO ₂ (CH ₂ ) ₁₇ CH ₃ ) is shown below, but is not limited thereto.

An ethanol solution of 35.5 g of stearyl mercaptan and 8.5 g of potassium hydroxide (177.5 g)
To g), 11.1 g of 1,2-dibromoethane was added dropwise at room temperature, and the mixture was stirred under reflux for 5 hours. After completion of the stirring, 0.
275 g of an 8% aqueous hydrochloric acid solution was added at room temperature. The precipitated crystals were collected by filtration, washed with water, and dried to obtain 18.4 g of 1,2-dioctadecylthioethane. Then 1,
18.4 g of 2-dioctadecylthioethane, 184 of acetic acid
g and a mixture of 184 g of aqueous hydrogen peroxide (35%)
The mixture was stirred at 90 ° C. for 5 hours. The reaction solution was added to ion-exchanged water at room temperature, and the precipitated crystals were separated by filtration and recrystallized from toluene to obtain 10.6 g of the desired compound.

The melting point of the linear hydrocarbon-containing compound (B) is
The temperature is preferably 50 ° C. or more and less than 100 ° C. The melting point is more preferably 60 ° C or higher, particularly preferably 70 ° C or higher, and more preferably 90 ° C or lower. If the melting point is too low, the heat resistance of the image decreases, and if it is too high, the clarification temperature range cannot be expanded, and the erasability decreases.

The mixing ratio between the linear hydrocarbon-containing compound (A) and the linear hydrocarbon-containing compound (B) is 80:20 to 1:99.
Is preferred. The mixing ratio of the linear hydrocarbon-containing compound (B) is preferably 97 or less, more preferably 95 or less, particularly preferably 90 or less, further preferably 30 or more, more preferably 40 or more, and particularly preferably 50 or more. preferable. The linear hydrocarbon-containing compounds (A) and (B) may be used alone or in combination of two or more. If the proportion of the straight-chain hydrocarbon-containing compound (B) is too high, there is a difference in transparency such that the transparency is high on the low temperature side and the transparency is low on the high temperature side, and the transparency cannot be uniform. On the other hand, if the ratio of the linear hydrocarbon-containing compound (B) is too low, sufficient transparency cannot be obtained.

Examples of the linear hydrocarbon-containing compound (B) include a fatty acid ester, a ketone having a higher alkyl group,
Dibasic acid ester, polyhydric alcohol difatty acid ester,
Examples thereof include, but are not limited to, aliphatic monoamide compounds and aliphatic monourea compounds.

The following are more specific examples, but the present invention is not limited to these examples. That is, specific examples of the fatty acid ester include, for example, octadecyl laurate, docosyl laurate, docosyl myristate, dodecyl palmitate, tetradecyl palmitate, pentadecyl palmitate, hexadecyl palmitate, octadecyl palmitate, triacontyl palmitate, palmitate Octadecyl, docosyl palmitate, vinyl stearate, propyl stearate, isopropyl stearate, butyl stearate, amyl stearate, heptyl stearate, octyl stearate, tetradecyl stearate, hexadecyl stearate, heptadecyl stearate, octadecyl stearate, Docosyl stearate, hexacosyl stearate, triacontyl stearate, dodecyl behenate, Phosphate octadecyl, docosyl behenic acid, lignoceric acid Torakoshiru include melissic acid myricyl like.

Specific examples of ketones having a higher alkyl group include, for example, 8-pentadecanone, 9-heptadecanone, 10-nonadecanone, 11-heneicosanone,
12-trichosanone, 14-heptacosanone, 16-hentriacontanone, 18-pentatriacontanone,
22-tritetracontanone, 2-pentadecanone, 2
-Hexadecanone, 2-heptacanone, 2-octadecanone, 2-nonadecanone and the like.

The dibasic acid ester is preferably a diester, and is represented by the following general formula (11). ROOC— (CH ₂ ) _n —COOR ′ ···················· (wherein R and R ′ represent an alkyl group, and the alkyl group preferably has 1 to 30 carbon atoms, and has 1 to 22 carbon atoms. R and R 'may be the same or different. N is preferably 1 to 30, and more preferably 2 to 20.

Specific examples include succinic acid diester, adipic acid diester, sebacic acid diester and 1,18-octadecamethylene dicarboxylic acid ester.

The polyhydric alcohol difatty acid ester of the organic low molecular weight substance used in the present invention is represented by the following general formula (1)
And 2). CH ₃ (CH ₂ ) _m-2 COO (CH ₂ ) _n OOC (CH ₂ ) _m-2 CH ₃ ... General formula (12) (where n is 2 to 40, preferably 3 to 30) And more preferably 4 to 22. m is 2 to 40, and preferably 3 to
30, more preferably 4 to 22. )

Specific examples include the following. 1,3-propanediol dialkanate 1,6-hexanediol dialkanate 1,10-decanediol dialkanate 1,18-octadecanediol dialkanate

Specific examples of the fatty acid monoamide include those represented by the following general formula (13). R ₁ —CONH—R ₂ ... General formula (13) (where R ₁ is a linear hydrocarbon chain having 1 to 25 carbon atoms, R ₂
Is a linear hydrocarbon chain having 1 to 26 carbon atoms, a methylol group, or hydrogen, and at least _one of R ₁ and R ₂ is a linear hydrocarbon chain having 10 or more carbon atoms. )

Examples of these include N-lauryl lauric amide, N-palmityl palmitic amide,
Stearyl palmitic amide, N-behenyl palmitic amide, N-palmityl stearamide, N-
Examples include stearyl stearamide, N-behenyl stearamide, N-palmityl behenamide, N-stearyl behenamide, N-behenyl behenamide and the like.

Specific examples of the aliphatic urea compound include, for example, those represented by the following general formula (14). R ₃ —NHCONH—R ₄ ... General formula (14) (where at least one of R ₃ and R ₄ is a linear hydrocarbon having 1 to 26 carbon atoms)

Examples of these include N-butyl-N'-
Stearyl urea, N-phenyl-N'-stearyl urea, N-stearyl-N'-stearyl urea, N-behenyl-N'-stearyl urea, N-stearyl-N'-
Behenyl urea, N-behenyl-N'-behenyl urea and the like.

The thermoreversible recording medium of the present invention preferably satisfies the following three conditions. (A) The upper limit temperature of transparency is 115 ° C. or more. (B) The temperature difference between the upper limit temperature of transparency and the lower limit temperature of cloudiness is 20.
℃ or less (c) Transparency temperature range is 30 ℃ or more Transparency upper limit temperature (Ttu), opacity lower limit temperature (Tsl), temperature difference between clarification upper limit temperature and opacity lower limit temperature (ΔTts), clarification start temperature ( Tta) and the transparency temperature range (ΔTw) are determined as follows.

First, a clouded thermoreversible recording medium is prepared. To use a clarified medium or a medium that is not sufficiently clouded, the medium is previously clouded by pressing the medium against a hot plate that has been sufficiently heated and heating. The heating time may be about 10 to 30 seconds. To confirm that the heating temperature is sufficient for clouding, it is sufficient to re-heat at a temperature slightly higher than that temperature (for example, a temperature higher by 10 ° C.). If the turbidity does not change between the two, it means that the initial heating temperature was sufficiently high to make the turbidity. If the turbidity is higher when heating at a slightly higher temperature, it means that the temperature was still lower at the initial temperature, and the same may be repeated again by increasing the heating temperature.

Next, the clouded recording medium is heated while changing the temperature, and the temperature at which the recording medium becomes transparent is examined. A thermal gradient tester (HG-100 manufactured by Toyo Seiki) is used for heating the recording medium. This thermal gradient tester has five heating blocks, each block can set the temperature individually, it is also possible to control the heating time and pressure, and under the set conditions,
The media can be heated at five different temperatures at once. Specifically, the heating time is 1 second, the pressure at the time of heating is about 2.5 kg / cm ² , and the heating temperature is an isothermal interval of 1 to 5 ° C. from a low temperature at which whiteness does not change even when heated. To a temperature at which the solution becomes sufficiently cloudy. To prevent the medium from sticking to the heat block, use a thin (10μ)
m or less) The film may be placed on top. After heating in this manner, the temperature was cooled to room temperature, and the density of the portion heated at each temperature was measured using a Macbeth RD-914 reflection densitometer.
A graph is created with the horizontal axis representing the set temperature of the thermal gradient tester and the vertical axis representing the reflection density. When the medium uses a transparent support, a sheet that absorbs light or a sheet that regularly reflects light on which a metal such as Al is deposited is placed on the back of the medium to measure the density. The graph is completed by plotting the density values for each temperature and connecting the plotted adjacent points with a straight line. The created graph usually has a trapezoidal shape as shown in FIG.

These data are also affected by the thickness and material of the medium including the heat-sensitive layer and the support. If the thickness of the medium is 300 μm or less, it is not affected by the thickness, and almost the same data can be obtained.
300μm thickness by shaving or peeling off the support side
It is sufficient to make the following or convert the thickness. Any material can be used as long as it is mainly composed of a polymer, but in the case of a metal or the like, conversion is necessary.

From this graph, the above-mentioned transparent upper limit temperature, white turbidity lower limit temperature and the like are read and calculated. First, the maximum density value (Dmax) is read in this graph. Then y
Draw a line of = 0.7 × Dmax and select plot points with higher density than this line. The number of plot points is preferably 5 to 20 points. If the number is small, the subsequent calculation result will be uncertain. When the number of plot points is small, it is necessary to narrow the temperature interval for heating in the above-mentioned thermal gradient tester and increase the number. Among the selected plot points, those having a high density value and those having a low density value are excluded by the same number, and the average of the density values of the remaining plot points is defined as an average transparent density (Dtav). The ratio of excluding large and small density values is 10 to 30%, preferably 15 to 25%, of the selected plot points. By excluding high and low density values, an accurate value of the transparent density of the medium can be calculated.

Next, the transparent lower limit density (Dtm) is calculated by the following equation (I).

Dtm = Dtav−0.2 × (Dtav−Dmin) Equation (I) where Dmin is the maximum cloudiness density, the temperature is raised, and three adjacent plot points are set. Is within the density value 0.3, it is calculated from the average value of the density at the three points. D
tm represents a density which is almost transparent visually when the density is equal to or higher than this density.

Further, a line of y = Dtm is drawn on the graph,
The temperature at the intersection with the concentration temperature curve is determined. Among these intersections, the lower temperature side is defined as the lower limit temperature of transparency (Ttl), and the higher temperature side is defined as the upper limit temperature of transparency (Ttu). The clearing temperature width (ΔTw) is obtained by the formula (II).

ΔTw = Ttu−Ttl (2)

The upper limit of cloudiness (Ds) is calculated by the formula (II)
Calculated by I).

Ds = Dmin + 0.1 × (Dtav−Dmin) (3)

A line of y = Ds is drawn on the graph, and the temperature at the intersection of the density-temperature curve and the portion where the color changes from transparent to cloudy is defined as the clouding lower limit temperature (Tsl).

The difference between the upper limit temperature for clearing and the lower limit temperature for clouding (Δ
Tts) is obtained by equation (IV).

## EQU4 ## ΔTts = Tsl-Ttu... Equation (IV)

The clearing start density (Dta) is given by the following equation (V)
Is required.

Dta = Dmin + 0.25 × (Dtav−Dmin) (Equation 5)

The transparency start temperature (Tta) is determined from the intersection of y = Dts and the graph as shown in FIG.

The upper limit temperature (Ttu) for making transparent transparent is preferably 115 ° C. or higher. As Ttu becomes hot,
The transparency temperature range can be expanded without lowering the image durability. The upper limit temperature for transparency (Ttu) is preferably 120 ° C. or higher, more preferably 125 ° C. or higher, and 130 ° C.
The above is particularly preferred. The higher the temperature, the higher the printing sensitivity. Ttu is preferably 170 ° C. or less, and 1
It is more preferably at most 60 ° C, particularly preferably at most 150 ° C. The lower the temperature, the higher the printing sensitivity.

The difference between the upper limit temperature of transparency and the lower limit temperature of cloudiness (Δ
Tts) is preferably 20 ° C. or lower. If ΔTts is greater than this, the temperature at which the cloudiness becomes unnecessarily high, so that when forming a cloudy image, a very high energy is required. The cloudiness of the image is reduced. Δ
Tts is preferably 15 ° C. or lower, more preferably 10 ° C. or lower.

The clearing start temperature (Tta) is preferably lower than 95 ° C., more preferably 90 ° C. or lower, particularly preferably 85 ° C. or lower, particularly preferably 70 ° C. or higher, and particularly preferably 75 ° C. or higher. When the temperature is low, the erasability is improved, and when the temperature is high, the image heat resistance is improved.

It is preferable that the transparentizing temperature range (ΔTw) is 30 ° C. or more. If ΔTw is smaller than this, the erasability will decrease. The transparency temperature range (ΔTw) is more preferably 40 ° C. or higher, further preferably 45 ° C. or higher, and particularly preferably 50 ° C. or higher. The wider the temperature range, the better the erasability. ΔTw is preferably 100 ° C. or lower, more preferably 90 ° C. or lower, and particularly preferably 80 ° C. or lower. In particular, when the transparency temperature width (ΔTw) becomes wider, there is an advantage that uniform erasing becomes possible even if the processing speed at the time of erasing is increased. ΔTw in this case is preferably 60 ° C. or higher,
70 ° C. or higher is more preferable. In particular, the clearing temperature range (ΔT
If w) becomes wider, there is an advantage that uniform erasing becomes possible even if the processing speed at the time of erasing is increased. In this case, ΔTw is preferably at least 60 ° C, more preferably at least 70 ° C.

The point of producing such a thermoreversible recording medium is a low molecular substance to be used. That is, a straight-chain hydrocarbon-containing compound (A) having a melting point of 120 ° C. or more from the above-mentioned straight-chain hydrocarbon-containing compounds, and a straight-chain having a melting point of 30 ° C. or more lower than the melting point of the straight-chain hydrocarbon-containing compound (A). This is achieved by mixing and using the hydrocarbon-containing compound (B).

The resin base material used for the heat-sensitive layer is a material that forms a layer in which organic low-molecular substances are uniformly dispersed and held, and that affects the transparency at the time of maximum transparency. For this reason, the resin base material is preferably a resin having good transparency, mechanical stability, and good film formability. The glass transition temperature of the resin matrix is 50
C. or higher, more preferably 60 ° C. or higher,
C. or more is particularly preferable, and further preferably less than 100.degree. C., particularly preferably less than 90.degree. If the glass transition temperature is too low, the heat resistance of the image decreases. If the glass transition temperature is too high, the erasability decreases.

The gel fraction of the resin matrix is preferably at least 30%, more preferably at least 50%, further preferably at least 70%, particularly preferably at least 80%. When the gel fraction value is small, the durability in repeated use decreases. To improve the gel fraction, a curable resin that is cured by heat, UV, EB, or the like may be mixed into the resin base material, or the resin base material itself may be cross-linked.

As a method for measuring the gel fraction, the membrane was peeled off from the support, the initial weight of the membrane was measured, and then the membrane was dried.
It was sandwiched between 00 mesh wire nets, immersed in a solvent in which the resin before cross-linking was soluble for 24 hours, dried under vacuum, and the weight after drying was measured. The gel fraction is calculated by the following equation. Gel fraction (%) = [weight after drying (g) / initial weight (g)] × 100

When calculating the gel fraction by this calculation, the calculation is performed excluding the weight of organic low-molecular substance particles other than the resin component in the heat-sensitive layer. At this time, if the weight of the organic low-molecular substance is not known in advance, the weight ratio is determined from the area ratio per unit area and the specific gravity of the resin and the organic low-molecular substance by cross-sectional observation with TEM, SEM, etc. The substance weight may be calculated to calculate the gel fraction value.

At the time of the above measurement, a reversible thermosensitive layer is provided on the support, and another layer such as a protective layer is laminated thereon, or between the support and the thermosensitive layer. If there are other layers, as described above,
Check the thickness of the reversible thermosensitive layer and other layers by cross-sectional observation with SEM, etc., shaving the surface for the thickness of the other layers, exposing the surface of the reversible thermosensitive layer, and peeling the reversible thermosensitive layer Then, the gel fraction may be measured in the same manner as in the above measuring method. In this method, if there is a protective layer made of an ultraviolet curable resin or the like on the upper layer of the heat-sensitive layer, the thickness of the protective layer should be reduced and the surface of the heat-sensitive layer should be slightly reduced in order to minimize the incorporation of this layer. It is necessary to prevent the effect on the gel fraction value.

These resins are preferably crosslinked. In the crosslinked medium, the structure inside the heat-sensitive layer hardly changes even when printing and erasing are repeated, and the repeated durability is improved, for example, there is no decrease in turbidity and transparency. When crosslinking, hydroxyl group, carboxyl group, epoxy group,
It preferably has a functional group such as an acryloyl group and a methacryloyl group. Examples of the method of crosslinking include thermal crosslinking and irradiation by UV or EB. It is preferable to add a crosslinking agent such as an isocyanate compound or a functional acrylic or methacrylic monomer to perform crosslinking.

Examples of such a resin include polyvinyl chloride;
Vinyl chloride copolymers such as vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-vinyl alcohol copolymer, vinyl chloride-vinyl acetate-maleic acid copolymer, vinyl chloride-acrylate copolymer; poly Vinylidene chloride-based copolymers such as vinylidene chloride, vinylidene chloride-vinyl chloride copolymer and vinylidene chloride-acrylonitrile copolymer; polyester; polyamide; polyacrylate or polymethacrylate or acrylate-methacrylate copolymer; Can be Of course, these resins may be used alone or in combination of two or more.

In the case of a combination of a thermoplastic resin having a hydroxyl group and an isocyanate compound, the isocyanate compound is preferably used by mixing a chain type isocyanate compound and a cyclic isocyanate compound. When only a chain type isocyanate compound is used, the crosslinked resin is usually soft and the erasability is improved. However, if the heat-sensitive layer is too soft, there is a drawback that the repetition durability and the image heat resistance are reduced. Conversely, when only a cyclic isocyanate compound is used, the crosslinked resin becomes rigid and the repeated durability and the image heat resistance are improved, but there is a disadvantage that the erasability is reduced. By using a mixture of a chain isocyanate compound and a cyclic isocyanate compound, it is possible to achieve both erasability, durability, and heat resistance.

The mixing ratio between the chain isocyanate compound and the cyclic isocyanate compound is preferably from 90:10 to 10:90, more preferably from 90:10 to 30:70, particularly preferably from 80:20 to 30:70. preferable. As the amount of the chain type isocyanate compound increases, the erasing rate and the maximum erasing slope can be improved, and thus the contrast can be improved. As the chain isocyanate compound, for example, a chain compound having a hydroxyl group such as triol and an aliphatic isocyanate such as hexamethylene diisocyanate are reacted directly or via one or more ethylene oxide or propylene oxide. The molecular weight of the chain isocyanate compound is preferably 500 or more,
More preferably, more preferably 1000 or more,
Moreover, 5000 or less is preferable, 4000 or less is more preferable, and 3000 or less is especially preferable. If the molecular weight is too small, the crosslinked coating film will not easily have a flexible structure, so that the erasability will be reduced. If the molecular weight is too large, the molecules will be difficult to move and the degree of crosslinking will be reduced, resulting in reduced durability. The molecular weight per one isocyanate group is preferably 250 or more, more preferably 300 or more, particularly preferably 400 or more, and preferably 2,000 or less, more preferably 1500 or less, and particularly preferably 1,000 or less. 1
If the molecular weight per two isocyanate groups is too small, the crosslinked coating film will not easily have a flexible structure, resulting in reduced erasability. If the molecular weight is too large, the molecules will be difficult to move, resulting in a reduced degree of crosslinking and reduced durability. I do.

The cyclic isocyanate compound is an isocyanate compound having a benzene ring or an isocyanurate ring. Among them, the type having an isocyanurate ring is preferably used because it does not cause yellowing. The cyclic isocyanate compound also preferably has a chain structure such as an alkylene chain in addition to the cyclic structure. The molecular weight of the cyclic isocyanate compound is preferably at least 100, more preferably at least 200, particularly preferably at least 300,
It is preferably less than 1000, more preferably less than 700. If the molecular weight is too small, the film will evaporate due to heating during film formation and the film cannot be crosslinked, resulting in reduced durability. If the molecular weight is too large, a rigid structure cannot be formed, and the durability decreases.

As the mixture of the chain isocyanate compound and the cyclic isocyanate compound, the above materials may be mixed, or a mixed product may be used. As a product of the mixture, for example, "Coronate 2" manufactured by Nippon Polyurethane Co., Ltd.
298-90T "and the like, but are not limited thereto.

The thickness of the heat-sensitive layer in the thermoreversible recording medium of the present invention is preferably 1 to 30 μm, more preferably 2 to 20 μm, and particularly preferably 4 to 15 μm. If the recording layer is too thick, heat distribution will occur in the layer, making it difficult to achieve uniform transparency. On the other hand, if the heat-sensitive layer is too thin, the turbidity decreases and the contrast decreases. The turbidity can be increased by increasing the amount of the fatty acid in the recording layer and by crosslinking the resin in the thermosensitive layer. The ratio between the organic low-molecular substance and the resin in the heat-sensitive layer was 2: 1 to 1 by weight.
About 1:16 is preferable, 1: 2 to 1: 8 is more preferable, 1: 2 to 1: 5 is still more preferable, and 1: 2 to 1: 4 is preferable.
Is particularly preferable, and 1: 2.5 to 1: 4 is more preferable. If the ratio of the resin is less than this, it becomes difficult to form the organic low-molecular substance in the film held in the resin, and if it is more than this, it becomes difficult to make the film opaque because the amount of the organic low-molecular substance is small. .

Further, a protective layer can be provided on the heat-sensitive layer to protect the heat-sensitive layer. Examples of materials for the protective layer (thickness: 0.1 to 5 μm) laminated on the heat-sensitive layer include silicone rubber, silicone resin (described in JP-A-63-221087), and polysiloxane graft polymer (JP-A-63-21087). No. 317385), an ultraviolet curable resin or an electron beam curable resin (described in JP-A No. 02-566). These may contain an organic or inorganic filler.

Further, an intermediate layer can be provided between the protective layer and the heat-sensitive layer in order to protect the heat-sensitive layer from a solvent, a monomer component, and the like of the protective layer forming solution (Japanese Patent Laid-Open No. 1-133).
No. 781). As the material of the intermediate layer, those listed as the resin base material in the heat-sensitive layer and other thermosetting resins, thermoplastic resins, UV-curable resins, and EB-curable resins described below can be used. That is, polyethylene, polypropylene, polystyrene, polyvinyl alcohol, polyvinyl butyral, polyurethane, saturated polyester, unsaturated polyester, epoxy resin, phenol resin, polycarbonate, polyamide and the like can be mentioned. The thickness of the intermediate layer is preferably about 0.1 to 2 μm. Below this, the protective effect is reduced, and above this, the thermal sensitivity is reduced.

Further, a layer for regular reflection of light may be provided between the support and the heat-sensitive layer to improve the contrast. This light reflection layer is usually formed by depositing a metal such as aluminum to a thickness of about 100 to 1000 mm.

By providing both the heat-sensitive layer capable of reversible display as described above and the information storage section on the same card, a part of the information stored in the information storage section is displayed on the heat-sensitive layer, so that the card is owned. A person or the like can check information only by looking at the card without any special device, and the convenience is improved. The information storage unit may be anything that can store necessary information, but magnetic recording, contact type IC, non-contact type IC, and optical memory are preferable. As the magnetic recording layer, usually used iron oxide, barium ferrite or the like and a PVC-based, urethane-based or nylon-based resin, etc., are formed by coating on a support, or without using a resin by a method such as evaporation or sputtering. It is formed. The magnetic recording portion may be provided on the surface of the support opposite to the heat-sensitive layer, or may be provided between the support and the heat-sensitive layer or on a part of the heat-sensitive layer. Further, the reversible thermosensitive material used for display may be used for the storage unit by a barcode, a two-dimensional code, or the like. Among them, magnetic recording and IC are more preferable.

In the thermoreversible recording medium of the present invention, a thermoreversible recording label can be obtained by providing an adhesive layer or an adhesive layer on the surface of the support opposite to the surface on which the thermosensitive layer is formed. A commonly used material for the adhesive layer or the pressure-sensitive adhesive layer can be used. Specific examples include urea resin, melamine resin, phenol resin, epoxy resin, vinyl acetate resin, and vinyl acetate-
Acrylic copolymer, ethylene-vinyl acetate copolymer,
Acrylic resin, polyvinyl ether resin, vinyl chloride-vinyl acetate copolymer, polystyrene resin, polyester resin, polyurethane resin, polyamide resin, chlorinated polyolefin resin, polyvinyl butyral resin, acrylate ester Examples include, but are not limited to, copolymers, methacrylate-based copolymers, natural rubber, cyanoacrylate-based resins, silicone-based resins, and the like. The material of the adhesive layer or the pressure-sensitive adhesive layer may be a hot melt type. A release paper may be used, or a non-release paper type may be used.

By providing the adhesive layer or the pressure-sensitive adhesive layer as described above, the adhesive layer can be applied to the entire surface or a part of a thick substrate such as a PVC card with a magnetic stripe, which is difficult to apply the heat-sensitive layer. Thereby, the convenience of the medium is improved, for example, a part of the information stored in the magnetic field can be displayed. The thermoreversible recording label provided with such an adhesive layer or pressure-sensitive adhesive layer can be used not only for the above-mentioned PVC card with magnetism but also for IC card.
It can also be applied to thick cards such as cards and optical cards.

Further, these thermoreversible recording labels can be used as replacements for display labels on a disk cartridge containing a rewritable disk such as a floppy (registered trademark) disk or MD or DVD-RAM. FIG. 3 shows an example in which a thermoreversible recording label is stuck on an MD disk cartridge. Furthermore, in the case of a disk such as a CD-RW that does not use a disk cartridge, a thermoreversible recording label can be directly attached to the disk or a heat-sensitive layer can be provided directly on the disk. By doing so, it is possible to apply to applications such as automatically changing the display content according to the change of the storage content.
FIG. 4 shows an example in which a thermoreversible recording label is stuck on a CD-RW. It is also possible to affix a thermoreversible recording label on a write-once disc such as a CD-R and rewrite and display a part of the storage information additionally written on the CD-R. FIG. 5 shows that AgInSbT
Optical information recording medium (CD using e-type phase change type storage material)
-RW) on which a thermoreversible recording label is formed. The basic configuration is such that a first dielectric layer, an optical information storage layer, a second dielectric layer, a reflective heat dissipation layer, and an intermediate layer are provided on a base having a guide groove, and a hard coat layer is provided on the back surface of the base.
Further, a thermoreversible recording label is stuck on the intermediate layer.
The dielectric layers need not necessarily be provided on both sides of the recording layer. However, when the substrate is made of a material having low heat resistance such as polycarbonate resin, it is desirable to provide the first dielectric layer.

Further, as shown in FIG. 6, it may be used as a display label of a video tape cassette. As a method of providing a thermoreversible recording function on a thick card, a disc cartridge or a disc, in addition to the method of applying the thermoreversible recording label described above, a method of directly applying a thermosensitive layer on them, or a method of applying a thermosensitive layer on another support in advance. There is a method of forming a layer and transferring the heat-sensitive layer onto a thick card, a disk cartridge or a disk. In the case of transfer, an adhesive layer such as a hot melt type or an adhesive layer may be provided on the heat-sensitive layer. When sticking a thermoreversible recording label on a rigid object such as a thick card, disk, disk cartridge, or tape cassette, or when providing a heat-sensitive layer, the contact with the thermal head is improved to make the image uniform. It is preferable to provide a layer or sheet that is elastic and forms a cushion between the rigid substrate and the label or heat-sensitive layer for forming.

For example, the thermoreversible recording medium of the present invention has the structure shown in FIG.
As shown in (a), a film in which a reversible thermosensitive recording layer (13) and a protective layer (14) are provided on a support (11). As shown in FIG. On the (11), an aluminum reflective layer (12) and a reversible thermosensitive recording layer (1)
3), a film provided with a protective layer (14), or an aluminum reflective layer (12), a reversible thermosensitive recording layer (13) on a support (11), as shown in FIG. A film having a protective layer (14) and a magnetic recording layer (16) provided on the back surface of a support (11) is processed into a card (21) having a print display section (23) as shown in FIG. Shape.

Further, for example, as shown in FIG. 9A, an aluminum reflective layer (12), a reversible thermosensitive recording layer (13), and a protective layer (14) are provided on a support (11). The film may be processed into a card shape to form a depression (23) for accommodating an IC chip, and may be processed into a card shape. In this example, a rewritable recording section (24) is label-processed on a card-like reversible thermosensitive recording medium, and a recess (23) for embedding an IC chip is provided at a predetermined location on the back side of the reversible thermosensitive recording medium. The wafer (231) as shown in FIG. 9 (b) is assembled and fixed in the recess (23). The wafer (231) has an integrated circuit (2) on a wafer substrate (232).
33) and a plurality of contact terminals (234) electrically connected to the integrated circuit (233) are provided on the wafer substrate (232). This contact terminal (23
4) is exposed on the back side of the wafer substrate (232),
A dedicated printer (reader / writer) uses the contact terminals (23
It is configured such that predetermined information can be read or rewritten by making electrical contact with 4). An example of the function of the reversible thermosensitive recording card will be described with reference to FIG.

FIG. 10A is a schematic block diagram showing an integrated circuit (233), and FIG. 10B is a block diagram showing an example of data stored in a RAM. The integrated circuit (233) is composed of, for example, an LSI, and includes a CP capable of executing a control operation in a predetermined procedure.
U (235), a ROM (236) for storing operation program data of the CPU (235), and a RAM (237) for writing and reading necessary data.
Further, the integrated circuit (233) receives the input signal and
(235) and the CPU (23).
5) an input / output interface (238) for receiving an output signal from the device and outputting the signal to the outside, a power-on reset circuit, a clock generator, a pulse divider (interrupt pulse generator), and an address decoder (not shown) Circuit. The CPU (235) can execute the operation of the interrupt control routine in accordance with the interrupt pulse periodically given from the pulse dividing circuit. The address decode circuit decodes the address data from the CPU (235) and provides signals to the ROM (236), the RAM (237), and the input / output interface (238).
A plurality of (eight in the figure) contact terminals (234) are connected to the input / output interface (238), and predetermined data from the dedicated printer (reader / writer) is input from the contact terminals (234). Output interface (2
38) to the CPU (235). CPU
(235) responds to the input signal and outputs the data from the ROM (23)
According to the program data stored in 6), each operation is performed, and predetermined data and signals are output to the card reader / writer via the input / output interface (238).

As shown in FIG. 10B, the RAM
(237) indicates a plurality of storage areas (239a) to (239).
f). For example, the area (239a) stores the card number, the (239b) stores the ID data such as the name, address, and telephone number of the card owner, and the area (239c) can use the owner, for example. Information corresponding to the residual value or valuables is stored in the area (239).
d) (239e), (239f) and (239g) store information corresponding to used valuables or valuables.

A method and an apparatus for recording and erasing an image on the thermoreversible recording medium will be described below. For recording an image, an image recording means, such as a thermal head or a laser, capable of partially heating the medium on the image is used. For image erasing, an image erasing means such as a hot stamp, a ceramic heater, a heat roller, hot air, a thermal head, a laser, or the like is used. Among them, a ceramic heater is preferably used. By using the ceramic heater, the size of the apparatus can be reduced, a stable erased state can be obtained, and an image with good contrast can be obtained. The set temperature of the ceramic heater is preferably 100 ° C. or higher, more preferably 110 ° C. or higher, and particularly preferably 115 ° C. or higher.

Further, by using a thermal head as the image erasing means, the overall size of the apparatus can be further reduced, the power consumption can be reduced, and a battery-driven hand-held type apparatus can be realized. . If a single thermal head is used for both recording and erasing, the size can be further reduced. When recording and erasing with one thermal head, after erasing all previous images once, a new image may be recorded again, or the previous image may be erased at once by changing the energy for each image, and An overwrite method of recording an image is also possible. In the overwrite method, the time for recording and erasing is reduced, which leads to an increase in recording speed. When a card having a thermosensitive layer and an information storage unit is used, the above device also includes a unit for reading the storage of the information storage unit and a unit for rewriting.

FIG. 11 shows a specific example of the thermoreversible recording apparatus of the present invention. FIG. 11 shows a schematic example of an apparatus for erasing an image by a ceramic heater and forming an image by a thermal head according to the present invention. In the thermoreversible recording device of FIG. 11, first, information stored in a magnetic recording layer of a recording medium is read by a magnetic head, and then an image recorded on the reversible thermosensitive layer is heated and erased by a ceramic heater. Based on the information read by the magnetic head, the processed new information is recorded on the reverse thermosensitive layer by the thermal head. Thereafter, the information in the magnetic recording layer is also rewritten with new information.

That is, in the thermoreversible recording apparatus of FIG. 11, the thermoreversible recording medium (1) provided with the magnetic recording layer on the opposite side of the heat-sensitive layer moves along the transport path shown by the reciprocating arrow. It is conveyed or conveyed in the reverse direction in the apparatus along the conveyance path. The thermoreversible recording medium (1) is magnetically recorded or erased on the magnetic recording layer between the magnetic head (34) and the transport roller (31), and the image is erased between the ceramic heater (38) and the transport roller (40). For this reason, a heat treatment is performed, an image is formed between the thermal head (53) and the transport roller (47), and thereafter, it is carried out of the apparatus. However, rewriting of magnetic recording may be performed before or after image erasure by the ceramic heater. If desired, after passing between the ceramic heater (38) and the transport roller (40), or after passing between the thermal head (53) and the transport roller (47), the sheet is transported in the reverse direction through the transport path, and the ceramic heater ( 38), it is possible to perform the heat treatment again and the printing process again by the thermal head (53).

[0099]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to embodiments. All parts and percentages here are on a weight basis.

Example 1 Magnetic web (manufactured by Dainippon Ink Industries, Ltd. (Memory Dick DS)
-1711-1040: A magnetic reflection layer and a self-cleaning layer were coated on a transparent PET film having a thickness of 188 μm), and a light reflection layer was formed by vacuum-depositing about 400 ° Al on the PET film side. A solution consisting of 10 parts of vinyl chloride-vinyl acetate-phosphate ester copolymer (manufactured by Denki Kagaku Kogyo Co., Ltd., Denka Vinyl # 1000P) 45 parts of methyl ethyl ketone 45 parts of toluene was applied thereon, and dried by heating to about 0.5 μm. A thick adhesive layer was provided. Next, 26 parts of a vinyl chloride copolymer (M110, manufactured by Zeon Corporation) was added to methyl ethyl ketone 230
6 parts CH ₃ (CH ₂ ) ₁₇ NHCOCONH (CH ₂ ) ₁₇ CH ₃ (Miyoshi Oil & Fat Co., Ltd.) 4 parts to the resin solution dissolved in the glass solution in the glass bottle Was placed therein and dispersed for 48 hours using a paint shaker (manufactured by Asada Tekko Co., Ltd.) to prepare a uniform dispersion. 4 parts of an isocyanate compound (Coronate 2298-90T, manufactured by Nippon Polyurethane Co., Ltd.) was added to the dispersion to prepare a heat-sensitive layer solution, which was heated and dried on the adhesive layer of the PET film having the magnetic recording layer, and further heated at 60 ° C. The resin was stored for 72 hours in an environment to crosslink the resin, and a heat-sensitive layer having a thickness of about 10 μm was provided.
On this heat-sensitive layer, a solution consisting of 10 parts of a urethane acrylate-based UV-curable resin, 10 parts of a 75% butyl acetate solution (manufactured by Dainippon Ink and Chemicals, Inc., Unidic C7-157), and 10 parts of isopropyl alcohol was applied using a wire bar. After heating and drying, 8
UV light is irradiated with a high-pressure mercury lamp of 0 w / cm and cured.
A protective layer having a thickness of about 3 μm was provided to prepare a thermoreversible recording medium.

Example 2 8 parts of behenyl behenate, CH ₃ (CH ₂ ) ₁₇ NHCOCONH (CH ₂ ) ₁₇ C
Except that of H ₃ and 2 parts to prepare a thermoreversible recording medium in the same manner as in Example 1.

Example 3 9 parts of behenyl behenate, CH ₃ (CH ₂ ) ₁₇ NHCOCONH (CH ₂ ) ₁₇ C
Except that of H ₃ and 1 parts to prepare a thermoreversible recording medium in the same manner as in Example 1.

Example 4 9.5 parts of behenyl behenate, CH ₃ (CH ₂ ) ₁₇ NHCOCONH (C
A thermoreversible recording medium was prepared in the same manner as in Example 1 except that 0.5 parts of H ₂ ) ₁₇ CH ₃ was used.

Example 5 A thermoreversible recording medium was prepared in the same manner as in Example 2, except that behenyl behenate was changed to diheptadecyl ketone (wax KS, manufactured by Nippon Kasei Co., Ltd.).

Example 6 A thermoreversible recording medium was prepared in the same manner as in Example 2 except that behenyl behenate was changed to ethanolamine distearate (Suriade S, manufactured by Nippon Kasei Co., Ltd.).

Example 7 CH ₃ (CH ₂ ) ₁₇ NHCOCONH (CH ₂ ) ₁₇ CH ₃ was converted to CH ₃ (CH ₂ ) ₁₆ CONHNHCO
A thermoreversible recording medium was prepared in the same manner as in Example 4, except that (CH ₂ ) ₁₆ CH ₃ (prototype of Miyoshi Yushi Co., Ltd.) was used.

Example 8 A thermoreversible recording medium was prepared in the same manner as in Example 7, except that behenyl behenate was changed to diheptadecyl ketone (wax KS, manufactured by Nippon Kasei Co., Ltd.).

Example 9 A thermoreversible recording medium was prepared in the same manner as in Example 7, except that behenyl behenate was changed to ethanolamine distearate (Suriade S, manufactured by Nippon Kasei Co., Ltd.).

Example 10 CH ₃ (CH ₂ ) ₁₇ NHCOCONH (CH ₂ ) ₁₇ CH ₃ was converted to CH ₃ (CH ₂ ) ₁₇ OOCNH (CH
_A thermoreversible recording medium was prepared in the same manner as in Example 4 except that ₂ ) ₆ NHCOO (CH ₂ ) ₁₇ CH ₃ (produced by Miyoshi Yushi Co., Ltd.).

Example 11 CH ₃ (CH ₂ ) ₁₇ NHCOCONH (CH ₂ ) ₁₇ CH ₃ was converted to CH ₃ (CH ₂ ) ₁₇ NHCOO (CH
₂ ) ₄ OOCNH (CH ₂ ) ₁₇ CH ₃ (produced by Miyoshi Oil & Fat Co., Ltd.), except that a thermoreversible recording medium was prepared in the same manner as in Example 2.

Example 12 CH ₃ (CH ₂ ) ₁₇ NHCOCONH (CH ₂ ) ₁₇ CH ₃ was converted to CH ₃ (CH ₂ ) ₁₇ SO ₂ (CH ₂ )
_A thermoreversible recording medium was prepared in the same manner as in Example 4, except that ₂ SO ₂ (CH ₂ ) ₁₇ CH ₃ (prototype of Miyoshi Oil & Fats Co., Ltd.) was used.

Example 13 A thermoreversible recording medium was prepared in the same manner as in Example 2 except that CH ₃ (CH ₂ ) ₁₇ NHCOCONH (CH ₂ ) ₁₇ CH ₃ was changed to the following material (prototype of Miyoshi Oil & Fats Co., Ltd.). Created.

Embedded image

Example 14 An adhesive layer, a heat-sensitive layer, and a protective layer were formed in the same manner as in Example 1 on an Al-deposited surface of an Al-deposited polyester film (# 50 Metal Me, manufactured by Toray Industries) having a thickness of about 50 μm. Further, an acrylic pressure-sensitive adhesive layer having a thickness of about 5 μm was provided on the back surface of the heat-sensitive layer surface of the support to produce a thermoreversible recording label. This label is made into a donut shape as shown in FIG. 4 and the CD-R is formed as shown in FIG.
An optical information recording medium having a reversible display function was fabricated by bonding the film on W. Using the optical information recording medium produced as described above, a CD-RW drive (MP620 manufactured by Ricoh Co., Ltd.)
0S), a part of the information (year, month, day, time, etc.)
Using a recording device having a recording means (thermal head) and an erasing means (ceramic heater), the recording energy of the thermal head was adjusted according to the change in the recording temperature of each medium, and the information was displayed and recorded on the thermosensitive layer and visualized. . Also,
Using the drive, the information in the storage layer of the optical information recording medium was rewritten, the recording device was erased by using a erasing means, the rewritten information was rewritten with a thermal head, and the rewritten information was rewritten to the heat-sensitive layer, and was displayed and recorded. Further, rewriting of this display record was repeated 100 times, but recording and erasing were possible.

Example 15 The thermoreversible recording label of Example 14 was stuck on a mini disk (MD) disk cartridge as shown in FIG. Part of the information stored on the MD (date, song name, etc.)
Using a recording device having a recording means (thermal head) and an erasing means (ceramic heater), the recording energy of the thermal head is adjusted according to the change in the recording temperature of each medium, and is displayed and recorded on the thermosensitive layer. Visualized. Further, rewriting of this display record was repeated 100 times, but recording and erasing were possible.

Comparative Example 1 A thermoreversible recording medium was produced in the same manner as in Example 1 except that the coating solution for the heat-sensitive layer was changed as follows. Behenic acid (reagent manufactured by SIGMA, purity 99%) 5 parts Eicosane diacid (manufactured by Okamura Oil Co., Ltd., SL-20-90) 5 parts Vinyl chloride-vinyl acetate copolymer 38 parts (manufactured by Union Carbide, VYHH) Tetrahydrofuran 210 parts Toluene 20 parts

Comparative Example 2 A thermoreversible recording medium was produced in the same manner as in Example 1, except that the coating solution for the heat-sensitive layer was changed as follows. In the heat-sensitive layer formed here, white particles were conspicuous and had poor uniformity. Behenyl behenate (Reagent, Sigma) 9.5 parts Ethylene bisbehenamide 0.5 parts (Nippon Kasei Co., Sripax B) Vinyl chloride-vinyl acetate copolymer 30 parts (Union Carbide, VYHH) 160 parts of tetrahydrofuran

The medium prepared as described above (Example 1)
To 13 and Comparative Examples 1 and 2), the following evaluations were performed.
Table 2 shows the results. (1) Contrast Visually evaluated. Good: 5 ← → Bad: 1 (2) Erasability In advance, make the medium transparent and use a reader / writer (R-3000) manufactured by Kyushu Matsushita Electric Industrial Co., Ltd. in a 23 ° C. environment.
After partially clouding with a thermal gradient tester, 50 sheets were erased at the optimum erasing temperature near the center of the erasing temperature,
The erasure state of the image was visually determined. ：: All erasable △ to △: Slight erasure remains a little. △: Occurrence of erasure sometimes occurs. X: erasure remains frequently. (3) Ammonia resistance. Transparent temperature range of medium before test and 8% ammonium carbonate.
The clarification temperature ranges of the media after immersion in an aqueous solution for 48 hours were compared. ○: No change ×: Large change

[0118]

[Table 2]

[0119]

As is apparent from the detailed and concrete description, according to the present invention, the temperature range for making transparent is widened,
Thermoreversible recording media, cards, disk cartridges, and disks that provide sufficient image erasability and high contrast even when the environmental temperature changes, and that provide sufficient turbidity even when stored in the presence of a basic substance , A tape cassette and a label, and an image processing method and apparatus suitable for using these thermoreversible recording media are provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a change in transparency by a thermoreversible recording medium according to the present invention.

FIG. 2 is a diagram for explaining an upper limit temperature for clearing, a lower limit temperature for clouding, a clearing start temperature, and a clearing temperature range of the thermoreversible recording medium according to the present invention.

FIG. 3 is a diagram showing an example in which a thermoreversible recording label is stuck on an MD disk cartridge.

FIG. 4 is a diagram showing an example in which a thermoreversible recording label is stuck on a CD-RW.

FIG. 5 is a diagram showing an example of a configuration in which a thermoreversible recording label is formed on an optical information recording medium (CD-RW) using an AgInSbTe-based phase change storage material.

FIG. 6 is a diagram showing a display label of the video tape cassette.

FIG. 7 is a diagram showing a layer configuration example of a thermoreversible recording medium according to the present invention.

FIG. 8 is a diagram illustrating an example of a thermoreversible recording medium according to the present invention.

FIG. 9 is a diagram illustrating another example of the thermoreversible recording medium according to the present invention.

FIG. 10 is a diagram illustrating a use example of the thermoreversible recording medium according to the present invention.

FIG. 11 is a diagram illustrating an example of a thermoreversible recording apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thermoreversible recording medium 11 Support 12 Aluminum reflective layer 13 Sensitive recording layer 14 Protective layer 15 Transparent PET film 16 Air layer 17 Adhesive layer 20 Magnetic coating layer 21 Card 22 Rewriting recording part 23 Depression part for IC chip 24 Label processing of rewriting recording section 34 Magnetic head 38 Ceramic heater 40 Transport roller 47 Transport roller 53 Thermal head 231 Wafer 232 Wafer substrate 233 Integrated circuit 234 Contact terminal 235 CPU 236 ROM 237 RAM 238 Input / output interface 239 Information on RAM storage area

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kunichika Moroboshi 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Fumio Kawamura 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Koji Kawai 4-66-1 Horikiri, Katsushika-ku, Tokyo Miyoshi Oil & Fat Co., Ltd. (72) Inventor Kazuo Hosoda 4-66-1 Horikiri, Katsushika-ku, Tokyo Miyoshi Oil & Fat Co., Ltd. (72 Inventor Masafumi Moriya 4-66-1 Horikiri, Katsushika-ku, Tokyo Miyoshi Oil & Fat Co., Ltd. (72) Inventor Katsuaki 4-6-6-1 Horikiri, Katsushika-ku, Tokyo Miyoshi Oil & Fat Co., Ltd. (72) Inventor Katsuyuki Sugiyama Tokyo 4-66-1, Horikiri, Katsushika-ku, Tokyo Miyoshi Oil & Fat Co., Ltd. F-term (reference) 2H111 HA07 HA18 HA23 HA35

Claims (13)

[Claims] 1. A thermoreversible recording medium comprising a resin base material and a low-molecular organic substance dispersed in the resin base material as a main component and having a heat-sensitive layer whose transparency reversibly changes depending on temperature. As low molecular substances, the following (1) to (7)
At least one of the carboxyl group-free linear hydrocarbon-containing compound (A) and a carboxyl group-free carboxyl group having a melting point lower than the melting point of the straight-chain hydrocarbon-containing compound (A) by 20 ° C. or more. A thermoreversible recording medium, wherein at least one of the chain hydrocarbon-containing compounds (B) is used as a mixture. (1) A linear hydrocarbon-containing compound having a urethane bond (2) A linear hydrocarbon-containing compound having a sulfonyl bond (3) A linear hydrocarbon-containing compound having an oxalic acid diamide bond (4) A straight chain having a diacylhydrazide bond (5) Linear hydrocarbon-containing compound having urea bond and urethane bond (6) Linear hydrocarbon-containing compound having urea bond and amide bond (7) Linear hydrocarbon containing multiple urea bonds Compound 2. The thermoreversible recording medium according to claim 1, wherein the linear hydrocarbon-containing compound (A) has a melting point of 100 ° C. or higher. 3. The thermoreversible recording medium according to claim 1, wherein the linear hydrocarbon-containing compound (B) has a melting point of 50 ° C. or more and less than 100 ° C. 4. The mixing ratio of the linear hydrocarbon-containing compound (A) to the linear hydrocarbon-containing compound (B) is 80:20 to 1: 9.
The thermoreversible recording medium according to any one of claims 1 to 3, wherein 5. The linear hydrocarbon-containing compound (B) is selected from a fatty acid ester, a ketone having a higher alkyl group, a dibasic acid ester, a polyhydric alcohol difatty acid ester, an aliphatic monoamide compound, and an aliphatic monourea compound. 5. The thermoreversible recording medium according to claim 1, wherein the thermoreversible recording medium is at least one kind. 6. The thermoreversible recording medium according to claim 1, wherein the following three conditions are satisfied. (A) The upper limit temperature of transparency is 115 ° C. or more. (B) The temperature difference between the upper limit temperature of transparency and the lower limit temperature of cloudiness is 20.
℃ or less (c) Transparency temperature range is 30 ℃ or more 7. The thermoreversible recording medium according to claim 1, wherein the gel fraction value of the resin base material is 30% or more. 8. The thermoreversible recording medium according to claim 1, wherein at least a part of the resin base material is cross-linked. 9. A thermoreversible recording medium according to claim 1, wherein said thermoreversible recording medium is provided in one selected from a card, a disc, a disc cartridge, and a tape cassette having an information storage unit. Card, disk, disk cartridge or tape cassette. 10. A thermoreversible recording section having at least the thermoreversible recording medium according to claim 1, a support, an adhesive layer or an adhesive layer, and the layers are laminated in this order. Characteristic thermoreversible recording label. 11. An image recording and / or erasing by heating using the thermoreversible recording medium, card, disk, disk cartridge, tape cassette or label according to any one of claims 1 to 10. Image processing method. 12. The image processing method according to claim 11, wherein an image is formed using a thermal head. 13. The image processing method according to claim 11, wherein the image is erased using a thermal head or a ceramic heater.