JPH0952445A - Reversible thermosensitive recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the display of a plurality of different colors by a structure wherein a coloring layer, which has coloring portions different from each other, and a recording layer, which contains an electron donating and colorable compound and an electron acceptable compound and in which developed color state and erased color state are repeated by means of the temperature condition of heat treatment, are laminated to each other. SOLUTION: This reversible heat-sensitive recording medium is produced by laminating at least a coloring layer 2 having a plurality of different coloring portions and a recording layer 5, which contains an electron donating and colorable compound and an electron acceptable compound and in which developed color state and erased color state are repeated by means of the temperature condition of heat treatment, to each other. Further, the reversible heat-sensitive recording material used in the recording layer 5 has a property to close lactone ring by coming the electron donating and colorable compound due to the softening of a polymer binder under heat, resulting in developing color. Furthermore, when the electron donating and colorable compound under developed color state is separated from the electron acceptable compound or comes into contact with the electron donating compound, the lactone ring portion is closed, resulting in erasing color.

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 medium capable of displaying plural kinds of colors.

[0002]

2. Related Art and Problems to be Solved by the Invention
A reversible thermosensitive recording material in which an electron-donating color-forming compound having a lactone ring portion (so-called leuco dye) is dispersed in a polymer binder is known.

In the reversible thermosensitive recording material, the polymer binder is softened by heating or the like, and the electron donating color-forming compound comes into contact with the electron accepting compound, whereby the lactone ring portion is opened to exhibit color. It has the property. Further, when separation from the electron-accepting compound or contact with the electron-donating compound occurs in the color-developed state, the lactone ring portion is closed again and the color disappears.

Generally, an electron-accepting compound is called a color developer and an electron-donating compound is called a color-reducing agent. Such a reversible thermosensitive recording material is known, for example, in JP-A-2-188294 and JP-A-4-247985.

The color developed by the reversible thermosensitive recording material depends on the molecular structure of the leuco dye. However, the color that can be displayed by the reversible thermosensitive recording material is the presence or absence of the color exhibited by the leuco dye,
That is, it is a change in two colors.

However, the reversible thermosensitive recording material is expected to be used as a display label which can be repeatedly used, for example, a display label such as a process instruction label and a component transportation instruction label. It is desirable to use by different colors to make it clear so as not to make a mistake.

Therefore, the present invention is to provide a reversible thermosensitive recording medium capable of displaying plural kinds of colors.

[0008]

The gist of the present invention is to provide a substrate with at least a colored layer having a plurality of different colored portions, an electron-donating color-forming compound and an electron-accepting compound, and a heat treatment. A reversible thermosensitive recording medium comprising a recording layer, which repeats a colored state and a decolored state depending on temperature conditions, laminated.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below step by step, but the present invention is not limited thereto.

FIG. 1 is a sectional view showing an example of the case where the reversible thermosensitive recording medium of the present invention is used for a display label. FIG. 2 shows the display surface of the display label shown in FIG.

As shown in FIG. 1, the display label used in the present invention comprises a base material 1 made of polyethylene terephthalate or paper having high strength, a colored layer 2 having a plurality of different colored portions, and an adhesive. Layer 3, base material 4 such as polyethylene terephthalate, recording layer 5, adhesive layer 6, and protective layer 7 are sequentially laminated.

In the above-mentioned display label, for example, a printed sheet in which the colored layer 2 is printed on the base material 1 and a recording sheet on which the recording layer 5 and the protective layer 6 are formed on the base material 4 are bonded with the adhesive 3. Can be manufactured by

As shown in FIG. 2, on the display surface of the display label, a plurality of colors provided on the coloring layer 2 are arranged in advance along the peripheral portion of the label. In FIG. 2, three types of colors are alternately arranged. Further, inside the recording layer 5, information necessary for a display label is written.

Although FIG. 2 shows a state in which three types of colors are arranged alternately for convenience, some of them may be hidden, as will be described later.

The reversible thermosensitive recording material used in the recording layer 5 has a leuco dye, a developer and a color-reducing agent dispersed in a polymer binder.

The leuco dye used in the heat-sensitive recording material of the present invention is not particularly limited as long as it has a lactone ring. For example, crystal violet lactone or a fluoran leuco dye, 3-diethylamino-6-methyl-7- Anilinofluorane, 3-dibutylamino-6-
Methyl-7-anilinofluorane, 2- (2-chloroanilino) -6-diethylaminofluorane, 2- (2-
Chloroanilino) -6-dibutylaminofluorane, 2
-Anilino-3-methyl-6- (N-ethylisopentylamino) fluorane, 3-cyclohexylmethylamino-6-methyl-7-anilinofluorane, 3-benzylethylamino-6-methyl-7-anilino Fluorane, 3-diethylamino-6-chloro-7-anilinofluorane, 3-methylpropylamino-6-methyl-7
-Such as Anilino Fluoran.

As the color developer, an organic acid having an alkyl group having 12 or more carbon atoms and at least one hydroxy group is used, and as the organic acid, a carboxylic acid, a phenolic compound, an aromatic carboxylic acid compound or a naphthalene compound is used. , Sulfonic acid compounds are preferred, for example, 2-hydroxylauric acid, 2-hydroxypalmitic acid, 2-hydroxystearic acid, 2-hydroxyeicoic acid, lauryl hydroxybenzoate, cetyl hydroxybenzoate, stearyl hydroxybenzoate, hydroxybenzoic acid. Eicosyl acid, lauryl gallate, cetyl gallate, stearyl gallate, eicosyl gallate, lauryl hydroxynaphthoate, cetyl hydroxynaphthoate, stearyl hydroxynaphthoate, eicosyl hydroxynaphthoate,
Examples thereof include lauryl dihydroxynaphthoate, cetyl dihydroxynaphthoate, stearyl dihydroxynaphthoate, and eicosyl dihydroxynaphthoate.

As the color-reducing agent, a compound having one or more amino groups in its molecule, for example, laurylamine, cetylamine, stearylamine, eicosylamine, methylethylamine, methylpropylamine, methylbutylamine, methylhexylamine, didodecylamine. , Trimethylamine, triethylamine, dimethylethylamine, dibenzylamine, tribenzylamine, piperazine, triphenylguanidine and the like.

As the polymer binder, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic acid copolymer, vinyl chloride-vinyl acetate-alcohol copolymer, other vinyl acetate compounds , Vinyl chloride copolymer, polyvinylidene chloride, vinylidene chloride copolymer, polyvinyl alcohol, polyester,
Examples thereof include polyamide, polyurethane, polystyrene, polymethacrylate, and copolymers thereof.

As the protective layer material, heat-resistant materials such as polyethylene terephthalate, polyetherimide, polyetheretherketone, polysulfone, polyphenylene sulfide, polyacrylate, polyether sulfone, polycarbonate, polyethylene naphthalate, polyimide and acrylic resin can be used. High resins and UV curable resins are used.

[0021]

Example The following composition was dispersed with a paint shaker for about 2 hours to prepare a coating liquid.

2- (2-chloroanilino) -6-diethylaminofluorane 10 parts by weight 2-hydroxypalmitic acid 20 parts by weight stearylamine 2 parts by weight Vinyl chloride-vinyl acetate copolymer 50 parts by weight Tetrahydrofuran 200 parts by weight Toluene 200 parts by weight The coating liquid was coated on the surface of a transparent polyethylene terephthalate resin film 4 having a thickness of 50 μm using a bar coater and dried to form a recording layer 5 having a thickness of 10 μm. A polyethylene terephthalate resin film having a thickness of 2 μm was attached onto the recording layer 5 via the adhesive layer 6 to form a protective layer 7, and a recording sheet was prepared.

Further, a printing sheet having a colored layer 2 in which three colors of color were alternately arranged in a rectangular shape was printed on the surface of a 100 μm white polyethylene terephthalate resin film 1.

The above-mentioned 50 μm polyethylene terephthalate resin film 4 of the recording sheet and the recording layer 2 of the printing sheet are bonded together via the adhesive layer 3 and then punched into a label shape to form a display label. did.

The necessary labels, numbers, and bars are applied to the obtained display label with a thermal head (0.30 mJ / dot).
Code etc. were printed in black. At the same time, one kind of color was left on the peripheral portion, and the other color portions were solidly printed in the same manner as the printing. The display label after printing has a black and color alternating arrangement at the peripheral portion, and necessary information is printed inside.

Next, when the display label was heated in a dryer at 90 ° C. for 30 seconds, the image was erased to the original state before printing. Such a display label was again printed with different characters and the like, and was filled with a color other than the color different from the previous time. The periphery was an alternating array of black and color. Even when such printing and erasing were repeated 50 times, no deterioration in performance was observed.

The color of the peripheral portion of the display label can be changed between black and color, black and color, black and color and the like. Therefore, by changing the color of the peripheral part of the display label, such as the process instruction label and the parts transportation instruction label, as necessary,
Make labels easy to distinguish, and make sure you know where you are going and how to use them.

In this embodiment, the leuco dye is colored black. By coloring in black, the color provided in the peripheral portion can be efficiently covered by the array, but it is not particularly necessary to limit the color to black. Further, although the color arrangement is provided on the peripheral portion, the color arrangement is not limited to the peripheral portion and may be anywhere as long as it is easy to distinguish.

[0029]

Since the reversible thermosensitive recording medium of the present invention can display a plurality of colors, the display of the color can be changed depending on the application to facilitate the application distinction.

[Brief description of drawings]

FIG. 1 is a sectional view of an example in which the reversible thermosensitive recording medium of the present invention is used for a display label.

FIG. 2 shows a display surface of the display label shown in FIG.

[Explanation of symbols]

 1 Base Material 2 Colored Layer 3 Adhesive Layer 4 Base Material 5 Recording Layer 6 Adhesive Layer 7 Protective Layer

Claims (1)

[Claims] 1. A substrate containing at least a colored layer having a plurality of different colored portions, an electron-donating color-forming compound and an electron-accepting compound, and having a colored state and a decolored state depending on heat treatment temperature conditions. A reversible thermosensitive recording medium characterized by being laminated with a recording layer which repeats.