JPH06106869A - Thermal recording medium - Google Patents

Abstract

PURPOSE:To provide a thermal recording medium with which corrosion of a metal thin film layer does not occur, multi-color printing of a coloring layer is possible, and applied development is effective. CONSTITUTION:A metal thin film layer 2 and a heat resisting protective layer 3 are layered in sequence on one face of a transparent support body 1 and a coloring layer 4 is provided on the other face. The metal thin film layer is fused, broken, and its masking property is taken away, so that pattern and color of the coloring layer is observed from the heat resisting protective layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for forms such as prepaid cards, pass tickets, entrance tickets, tickets, facsimile papers, computer output papers, tape / sheet recording media, thermal heads and laser beams. The present invention relates to a heat-sensitive recording medium that records information by heating with, for example.

[0002]

2. Description of the Related Art Conventionally, a thermal transfer ribbon has been used in a thermal recording method for recording image information such as characters and figures by causing chemical and physical changes by thermal energy from a thermal head or a laser beam. A method of recording an image by transferring a wax-based ink layer to the medium side having a recording layer and an image receiving layer using auxiliary materials such as, and a heat-sensitive recording layer using a leuco dye such as a fluoran dye as a coloring agent on the medium side. There are two methods: a method in which a chemical change is directly caused by a thermal head or the like for printing, and a machine side does not require auxiliary materials.

The former is widely used for the output of electronic calculators, color printers and the like, taking advantage of its high storability and easy colorization. The latter is widely used for the output of facsimiles and word processors because it has excellent thermal sensitivity that it develops color at a relatively low temperature, and because it does not use auxiliary materials, it is low cost and does not require maintenance on the machine side. ing.

However, the leucothermal method has the drawback that it develops color relatively easily due to fog and pressure due to its good thermal sensitivity, and that it develops easily when it is exposed to a polar organic solvent such as alcohol. It has drawbacks, and there are no items that are fully satisfactory in terms of chemical resistance, light resistance, water resistance, environment resistance such as heat resistance,
At present, its use is limited to temporary recording of image information.

In recent years, as a method for recording image information without using the latter auxiliary material, a metal thin film layer is used as a hiding layer, and the hiding property is lost by melting and destroying it by heat to make visible recording. A heat-sensitive recording medium to be used has been devised, and a heat-sensitive recording medium having an environment resistance far superior to that of the leucothermal method in terms of durability has come to be used.

[0006]

A thermal recording medium of this type is generally one in which a colored layer is provided on one surface of an impermeable support, and a metal thin film layer and a heat resistant protective layer are sequentially provided on the colored layer. Is. However, in the thermosensitive recording medium having this structure, the colored layer and the metal thin film layer are in contact with each other or are present in a very close distance, so that there is a problem of metal corrosion.

Further, since the metal thin film layer for recording information must be smooth, the coloring layer as the lower layer is required to have smoothness. Therefore, it is not possible to use a multi-color printing method such as gravure, screen, offset or the like, in which minute irregularities occur in the formation of the colored layer, and it is limited to a solid pattern of a single color.

Further, since the colored layer has to be provided in the first step, there is a problem that the application development is not effective and the manufacturing cost is disadvantageous.

[0009]

SUMMARY OF THE INVENTION The present invention has been studied and devised in view of the problems of the above-mentioned prior art. The invention according to claim 1 has a metal thin film on one surface on a transparent support. The heat-sensitive recording medium is characterized in that a layer and a heat-resistant protective layer are sequentially laminated, and a colored layer is provided on the opposite surface.

A second aspect of the present invention is based on the first aspect of the invention, and is a thermal recording medium characterized in that a thermal sensitizing layer is further provided between the transparent support and the metal thin film layer.

A third aspect of the present invention is based on the first aspect of the invention, and is a thermal recording medium characterized in that the colored layer is made of a magnetic material.

A fourth aspect of the present invention is based on the first aspect of the invention, and is a heat-sensitive recording medium characterized in that the colored layer is a multicolor pattern formed by a printing method.

[0013]

According to the first aspect of the invention, the pattern and color of the colored layer can be observed from the heat resistant protective layer side by melting and destroying the metal thin film layer to lose the hiding property. Further, since the transparent support is present between the metal thin film layer and the colored layer, the two layers do not come into contact with each other, and the problem of metal corrosion does not occur. Furthermore, since there is no metal thin film layer directly on the colored layer, it is possible to provide a colored layer by a multi-color printing method such as gravure, screen, offset or the like in which minute unevenness is generated, and an excellent design can be imparted. it can. Furthermore, since a semi-finished product provided with a metal thin film layer and a heat-resistant protective layer on a transparent support in advance and a colored layer is formed if necessary, different products can be manufactured.
Easy to apply.

According to the second aspect of the present invention, the transparent support 1 and the metal thin film layer 2 are firmly adhered to each other, and the thermal destruction of the metal thin film layer is facilitated.

According to the third aspect of the invention, since the colored layer is made of a magnetic material, it is possible to impart a function as a magnetic recording medium.

According to the fourth aspect of the invention, the image portion has a special hue without impairing the surface roughness of the metal thin film layer (thermosensitive recording layer), and an image which cannot be obtained with other thermal recording media. Is obtained.

The present invention will be described in detail below with reference to the drawings.

In FIG. 1, a metal thin film layer 2 is formed on one surface of a transparent support 1, a heat resistant protective layer 3 is formed on the metal thin film layer, and a colored layer 4 is provided on the opposite side. It is a basic configuration of the invention. In FIG. 2, the heat-sensitive sensitizing layer 5 is provided between the transparent support 1 and the metal thin film layer 2. FIG. 3 shows a structure in which the colored layer 4 is provided by a magnetic material, that is, the transparent support 1 has a magnetic recording function on the surface opposite to the metal thin film layer 2. In this case, the concealing layer 6 and the protective layer 7 may be sequentially laminated on the colored layer 4 if necessary. FIG. 4 shows a configuration in which the colored layer 4 is provided as a multicolor pattern (picture) instead of a single color. In this case, if the white hiding layer 6 is provided as necessary, the color reproducibility is improved. Get better.

The transparent support 1 is made of a polyethylene terephthalate film having mechanical strength, flexibility and flexibility, or a plastic film or glass made of a highly transparent polymer material such as polycarbonate, polyvinyl chloride or polyacrylate. A plate or the like is used as needed. In general, a film having a thickness of 50 to 1000 μm and having heat resistance capable of withstanding an instantaneous high temperature of 250 ° C. or higher is suitable as a support for a thermal recording medium.

The heat-sensitive sensitizing layer 5 is a layer having a heat-sensitive sensitizing function for adhering the transparent support 1 and the metal thin film layer 2 to each other and for facilitating thermal destruction of the metal thin film layer.
It is provided as needed.

As a material, a resin containing a polyester resin, a polyvinyl chloride resin, a vinyl chloride-vinyl acetate copolymer, a polyvinyl butyral resin, an acrylic resin, a polyurethane resin, an epoxy resin or the like as a main component is used.
For the purpose of improving the sensitivity, it is generally preferable that the resin is thermoplastic, but there are problems in processing the layers stacked above the heat-sensitive layer, that is, the metal thin film layer 2 and the heat-resistant protective layer 3. From the problems of solvent resistance and chemical resistance of the completed thermal recording medium, it is preferable to add the plasticizer and the curing agent such as isocyanate and melamine while adjusting them based on the design concept.

The metal thin film layer 2 is made of Sn, Te, In, A.
A single metal such as l, Bi, Zn, or Pb, or an alloy or compound of these metals can be formed by a method such as vacuum deposition, sputtering, plating, transfer, or laminating. A low melting point is advantageous for easy melting,
Mainly, a simple substance of Sn or an alloy of Sn is a material that is easy to use. The thickness of this metal thin film layer is about 100 to 5000 Å, and a recording function can be obtained. However, if it is too thin or too thick, the printing sensitivity decreases, so about 1000 Å is preferable.

The heat-resistant protective layer 3 is generally a gravure coating or a reverse roll coating obtained by adding an additive to a heat-resistant resin having a glass transition temperature of 70 ° C. or higher, such as an acrylic resin, an epoxy resin, or various ultraviolet curable resins. , Various coating methods such as knife coating and blade coating, and printing methods such as gravure printing and screen printing to provide a film thickness of about 1 to 10 μm. However, since a resin having a high heat resistance does not easily adhere to the metal thin film, a method of mixing it with a vinyl chloride resin or the like to improve the adhesiveness with the metal thin film may be adopted.

As the additives, various kinds of pigments, curing agents, lubricants and the like are used in appropriate amounts as needed. As the lubricant, silicone-based, metal stearate such as zinc stearate, and fluorine-based ones can be used, but in consideration of abrasion resistance, coating film protection during heating, and sliding performance, wax-based lubricant is used. Preferably, the melting point is in the range of 50 to 150 ° C. Paraffin wax, microcrystalline wax, carnauba wax, rice wax, montan wax, low molecular weight polyethylene wax, oxidized polyethylene wax, low molecular weight polypropylene wax, various fatty acids, monoamide type, bisamide type. , Various natural and synthetic waxes such as beef tallow, etc. are added alone or in a mixed system.

If a large amount of semi-finished products in which the metal thin film layer 2 and the heat-resistant protective layer 3 are provided on the transparent support 1 are prepared as the basic constitution of the thermosensitive recording medium, the coloring layer 4 which will be described later will have various hues. Various thermal recording media can be easily manufactured by providing the above.

The coloring layer 4 is a layer for imparting black, indigo, red, and other hues to distinguish it from a hue of an unrecorded portion such as a metallic tone (that is, glossiness) to a matte tone (that is, white color). It is nothing but the hue that appears when recording image information.

As the material of the colored layer 4, a pigment, a dye or a binder resin such as polyester resin, polyvinyl chloride resin, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral resin, acrylic resin, polyurethane resin or epoxy resin is used. In the case of imparting a magnetic recording function, a magnetic material is dispersed and dissolved.

The colored layer 4 may be formed by directly printing / coating a gravure ink, an offset ink, a screen ink, various coating paints, etc. on a transparent support, or separately prepared in the form of a foil or a sheet. It may be indirectly applied to the transparent support in the form of transfer or laminate. At this time, in particular, when a pattern such as a character or a pattern is provided in multiple colors by a printing method, a recorded image portion that appears due to thermal destruction has a special hue, and a special image can be recorded.

Further, the color tone is further adjusted on the colored layer 4,
A concealing layer for improving contrast and a protective layer for protecting the concealing layer and the colored layer may be provided.

The characteristic feature of the present invention is that the colored layer 4 is provided on the side opposite to the metal thin film layer (thermosensitive recording layer) as shown in FIG.
By providing a pattern including characters and pictures in multiple colors by a printing method, the image portion has a special hue without impairing the surface roughness of the metal thin film layer (heat-sensitive recording layer), and other heat-sensitive recording media This is where you can get images that cannot be obtained with. Further, if the metal thin film layer is completely destroyed, the entire pattern (pattern) is exposed, so that it can be applied to cards and tickets such as games and lottery tickets.

[0031]

EXAMPLES Examples of the present invention will be described in detail below.

[Example 1] As Example 1, the structure shown in FIG. 1 was manufactured.

A thermosensitive recording medium having the following layer structure was formed on a transparent support 1 made of a transparent hard vinyl chloride film having a thickness of 200 μm.

As the metal thin film layer 2, a concealing thin film having a film thickness of about 1000 Å was formed by a control method such that the resistivity on the surface of Sn was 1 Ω / □ by a vacuum deposition method.

A solvent-soluble resin having the following composition was used as the heat-resistant protective layer 3 and was coated at a coating thickness of 1.5 μm.

Silicon Acrylic Resin (44% Nonvolatile Content) Acridic BZ-1161: 100 parts made by Dainippon Ink and Chemicals Epoxy curing agent (80% Nonvolatile Content) Akridic BZ-1163: 20 parts made by Dainippon Ink and Chemicals Low molecular weight polyethylene wax dispersion (nonvolatile content 15%) AF (BASF, melting point 100 ° C) / toluene 20 parts Calcium carbonate 10 parts Alumina AKP30: Sumitomo Chemical Co., Ltd. 5 parts Diluting solvent 100 parts

As the coloring layer 4, a coloring paint having the following composition was applied to the opposite surface of the transparent support by a gravure method to give a coating thickness of 3 μm.
m.

Urethane resin type black ink Lamister R92 ink: Toyo Ink Manufacturing 100 parts Vinyl acetate vinyl resin (20% lacquer) VAGH: Union Carbide 30 parts Isocyanate curing agent Coronate HL: Nippon Polyurethane Industry 5 parts Diluting solvent Toluene / MEK / IPA 30 parts

Comparative Example 1 As Comparative Example 1, the colored layer in Example 1 was provided on the transparent support, and the metal thin film layer and the heat-resistant protective layer were sequentially provided on the colored layer in the same manner as in Example 1 to obtain a heat-sensitive material. A recording medium was obtained.

Example 2 As Example 2, the structure shown in FIG. 2 was manufactured.

A thermosensitive recording medium having the following layer structure was formed on a transparent support 1 having a thickness of 38 μm and made of transparent polyethylene terephthalate.

As the heat-sensitive sensitizing layer 5, the following resin paint was applied by a gravure method to a coating thickness of 1.5 μm, and then aging was carried out at 60 ° C. for 48 hours.

Acrylic-cellulosic resin (30% lacquer) VM-AL: Dainichi Seika Kogyo 100 parts 100% vinegar vinyl chloride resin (20% lacquer) S-REC C: Sekisui Chemical Co., Ltd. 30 parts Fine particle silica powder Aerosil 300: Nippon Aerosil Made 2 parts Isocyanate curing agent Coronate HL: Nippon Polyurethane Industry 5 parts Diluting solvent Toluene / MEK / Butanol 70 parts

As the metal thin film layer 2, as in the first embodiment, S
n thin film layers were formed. A coating composition having the following composition is provided as the heat-resistant protective layer 3 at a coating thickness of 1.5 μm, and then the coating is applied at 60 ° C.
Aged for 8 hours.

Regular dry type acrylic resin 56-1155: Dainippon Ink and Chemicals Co., Ltd. 50 parts Vinyl chloride-vinyl acetate copolymer VAGF: Union Carbide 20 parts Microcrystalline wax dispersion HI-DISPER3099: Gifu shellac factory 12 Part Isocyanate curing agent Duranate D24A100: Asahi Kasei 7 parts

As the colored layer 4, a colored paint having the following composition was applied to the opposite surface of the transparent support by a gravure method so as to have a thickness of 3 μm, and then aged at 60 ° C. for 48 hours.

Urethane Resin Red Ink Lamister R92 Beni: Toyo Ink Mfg. 100 parts Vinyl Acetate Vinyl Resin (20% Lacquer) VAGH: Union Carbide 30 parts Isocyanate Hardener Coronate HL: Nippon Polyurethane Industry 5 parts Diluent Solvent Toluene / MEK / IPA 30 parts

[Example 3] As Example 3, the structure shown in Fig. 3 was manufactured.

Example 3 uses a magnetic material for the colored layer 4,
This is a configuration to which a magnetic recording function is added.

A heat-sensitive recording medium having the following layer structure was formed on a transparent support 1 having a thickness of 188 μm and made of transparent polyethylene terephthalate.

As the heat-sensitive sensitizing layer 5, the following resin coating material was applied by a gravure method to a coating thickness of 1.5 μm and then aged at 60 ° C. for 48 hours.

Acrylic resin (40% lacquer) BR-53: 100 parts made by Mitsubishi Rayon 100% vinegar vinyl chloride resin (20% lacquer) S-REC A: 30 parts made by Sekisui Chemical Co., Ltd. 30 parts particulate resin powder Eposter M30: made by Nippon Shokubai Kagaku Kogyo 2 Parts Isocyanate curing agent Coronate HL: Nippon Polyurethane Industry 5 parts Diluting solvent Toluene / MEK / Butanol 70 parts

As the metal thin film layer 2, a Sn thin film was formed in the same manner as in Examples 1 and 2. As the heat resistant protective layer 3, the same protective layer as in Example 2 was formed.

As the colored layer 4, a colored magnetic coating composition having the following composition was applied to the opposite surface of the transparent support by a gravure method so as to have a coating thickness of 12 μm, and magnetic field orientation was applied in a horizontal magnetic field of about 3000 gauss, It was dried at a drying temperature of 110 ° C. for about 3 minutes.

Magnetic powder (1750 Oe, barium ferrite) 100 parts Vinyl chloride-vinyl acetate copolymer VAGF: Union Carbide 20 parts Polyurethane resin (nonvolatile content 30%) Samprene IB-114B: Sanyo Chemical Industries 15 parts Colored carbon black # 3000: Mitsubishi Kasei Kogyo 5 parts Dispersant Garfac RE-610: Toho Chemical Industry 3 parts Diluting solvent Toluene / MEK / MIBK 100 parts

The concealing layer 6 was formed by coating a coating composition having the following composition by 2 μm by a gravure method.

Polyester resin (30% lacquer) Byron 30SS: Toyobo 100 parts Aluminum paste Alpaste 7900: Toyo Aluminum 10 parts Diluting solvent Toluene / MEK 20 parts

Further, as a protective layer 7, a coating material having the following composition was provided by a gravure method to a thickness of 1.5 μm to obtain a heat-sensitive recording medium having a magnetic recording function.

Permanently dry acrylic resin (55% lacquer) A-136-55: Dainippon Ink and Chemicals Incorporated 100 parts Polyethylene wax dispersion (NV10%) High Flat TE-10P-3: Gifu Shellac Manufacturing 30 Part Diluting solvent Toluene / MEK / ethyl acetate 50 parts

[Comparative Example 2] As Comparative Example 2, the colored (magnetic recording) layer in Example 3 was provided on a transparent support, and the heat-sensitive sensitizing layer, the metal thin film layer, and the colored layer were formed on the colored layer in the same manner as in Example 3. A heat resistant protective layer was sequentially provided to obtain a heat sensitive recording medium having a magnetic recording function.

Example 4 As Example 4, the structure shown in FIG. 4 was manufactured.

Example 4 describes an example in which the colored layer 4 is provided with a multicolor pattern by a printing method.

As in Example 2, the heat-sensitive sensitizing layer 5, the metal thin film layer 2, and the heat-resistant protective layer 3 were provided on one side of the transparent support, and the colored layer 4 was formed on the opposite side to the following four colors. After printing a pattern with the ink, white ink is used as the concealing layer 6 in an amount of 2 μm in order to adjust the color tone and provide contrast.
The entire surface was printed with a thickness of m to obtain a thermal recording medium.

Urethane resin gravure ink Lamister R162 Red, Lamister R233 Yellow, Lamister R39 Indigo Lamister R92 Black, Lamister R63 White

Examples 1, 2, 3, 4 and Comparative Examples 1, 2
The heat-sensitive recording medium produced by was evaluated by the following method. The results are shown in Table 1.

[0066]

[Table 1]

○ It does not corrode at all. Fairly corroded.
× Corrosion is noticeable.

(1) Printing characteristics Printing density and background density when printing was performed with a thermal head (12 dots / mm) at a printing energy of 1.1 mJ / dot and an instantaneous surface temperature of 280 ° C. under a pressure of 40 g / cm. The difference (ΔOD) was evaluated (solid only). The measurement was carried out using Macbeth reflection densitometer RD918.

(2) Acid resistance Resistance was immersed in 5% acetic acid for 6 hours, and changes in background density due to corrosion of the metal thin film layer and decomposition of the heat resistant protective layer were observed.

(3) Alkali resistance It was immersed in a 5% sodium carbonate aqueous solution for 6 hours, and the change in background density due to corrosion of the metal thin film layer or decomposition of the heat resistant protective layer was observed.

(4) Salt Water Resistance A 5% saline solution was immersed in the solution for 5 days, and changes in background density due to corrosion of the metal thin film layer, decomposition of the heat resistant protective layer, etc. were observed.

[0072]

As shown in the comparison between Example 1 and Comparative Example 1 and the comparison between Example 3 and Comparative Example 2, the thermosensitive recording medium according to the present invention is provided with the coloring layer on the same side as the metal thin film layer. Compared with the conventional type, it is very resistant to corrosion such as acid resistance and salt water resistance without deteriorating the print density.

In forming the colored layer, gravure,
It is possible to use a multicolor printing method such as screen and offset, and it is possible to impart an excellent design.

Further, it is possible to meet the contradictory demands of mass productivity and small lot correspondence at the time of manufacturing.

[0075]

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a basic configuration of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a configuration of an exemplary embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a configuration of an exemplary embodiment of the present invention.

[Explanation of Codes] 1 transparent support 2 metal thin film layer 3 heat resistant protective layer 4 colored layer 5 heat sensitive layer 6 concealing layer 7 protective layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toru Endo 1-5-1, Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd.

Claims (4)

[Claims] 1. A heat-sensitive recording medium comprising a transparent support, a metal thin film layer and a heat-resistant protective layer, which are sequentially laminated on one surface of the transparent support, and a colored layer provided on the opposite surface thereof. 2. The heat-sensitive recording medium according to claim 1, further comprising a heat-sensitive sensitizing layer provided between the transparent support and the metal thin film layer. 3. The thermosensitive recording medium according to claim 1, wherein the colored layer is made of a magnetic material. 4. The thermosensitive recording medium according to claim 1, wherein the colored layer is a multicolor pattern formed by a printing method.