JPH0569659A - Discharge recording sheet - Google Patents

Abstract

(57) [Summary] [Object] To provide an electric discharge recording sheet which is excellent in chemical resistance and is capable of stably forming a clear, accurate and precise image even in the presence of chemicals. [Structure] A needle-like electrode and a metal thin film 3 which are composed of a base sheet 1, a metal thin film 3, and a transparent resin layer 4 and are arranged in close proximity to each other.
Is a discharge recording sheet for destroying the metal thin film 3 to form an image by discharge between the base sheet 1 and the metal thin film 3, and a chelating agent for chelating the metal thin film 3 such as gallic acid ester. The thing characterized by having provided the layer 2. Since the surface of the metal thin film 3 is chelated and the chemical resistance is improved, a clear, accurate and precise image can be stably formed even in the presence of chemicals, and the formed image deteriorates with time. Has a difficult effect.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge recording sheet provided with a colored base sheet and a metal thin film and a transparent resin layer which are sequentially laminated on the base sheet, and particularly, to improve chemical resistance. The present invention relates to an improved discharge recording sheet.

[0002]

2. Description of the Related Art Such an electric discharge recording sheet is well known in the prior art, and is disclosed in, for example, JP-A-1-115688.
It is described in JP-A No. 1-128873.

The discharge recording sheet a is colored as shown in FIG. 2, a base sheet a1, a metal thin film a2 laminated on the base sheet a1, and a submicron thickness laminated on the metal thin film a2. And a transparent resin layer a3 which is thin.

To form an image using this discharge recording sheet a, first, as shown in FIG. 2, the metal roll c connected to the anode of the power source b is brought into close contact with the transparent resin layer a3 and the power source The needle electrode d connected to the cathode of b is arranged close to the transparent resin layer a3 side of the discharge recording sheet a. In this case, the thin transparent resin layer a3 having a thickness of about submicron can transfer charges, and the metal thin film a1 is formed of the transparent resin layer a3.
Since it is electrically connected to the power source b via the electrode, when the needle electrode d is selectively energized while moving the needle electrode d, a discharge is generated between the energized needle electrode d and the metal thin film a2. This discharge is generated between the energized needle electrode d and the metal thin film a2 closest to the needle electrode d, and the metal thin film a2 and the transparent resin layer a3 in this region are destroyed and disappear. With the disappearance of the metal thin film a2, the base sheet a1 is exposed from the destroyed portion, and the portion of the base sheet a1 selectively exposed by the discharge is different from the color of the surrounding metal thin film a2. A recorded image such as a symbol or a photographic image is formed.

[0005]

By the way, when forming a recorded image as described above, the metal thin film a2 and the metal roll c need to be electrically connected through the transparent resin layer a3. The thickness is limited to submicron.

However, in such a thin transparent resin layer, permeation of chemicals such as alkaline chemicals easily occurs, and the permeation of chemicals such as alkaline chemicals easily corrodes the metal thin film to easily cause scumming, resulting in a clear image. There is a problem that it is difficult to form a recorded image.

Further, at the recorded image portion where the transparent resin layer a3 and the metal thin film a2 disappear due to the discharge, the end face of the metal thin film a2 is exposed to the atmosphere, so that the above recorded image is corroded by chemicals with the passage of time. There was a problem of easy deterioration.

The present invention has been made by paying attention to such a problem, and its problem is that it has excellent chemical resistance and is stable, clear, accurate and precise in the presence of chemicals. Another object of the present invention is to provide an electric discharge recording sheet which can form a recording image and in which the formed recording image is less likely to deteriorate with time.

[0009]

That is, the invention according to claim 1 is provided with a colored base sheet, a metal thin film and a transparent resin layer which are sequentially laminated on the base sheet, and the transparent resin layer is provided in the transparent resin layer. On the premise of a discharge recording sheet on which an image is formed by the base sheet exposed from the destroyed portion by causing a discharge between the needle electrode and the metal thin film arranged in close proximity A chelating agent layer for chelating the metal thin film is provided between the sheet and the metal thin film.

In such technical means, the chelating agent constituting the chelating agent layer is one which chelates the surface of the metal thin film and improves resistance to chemicals such as alkaline chemicals. The chelating agent not only chelates the lower surface side of the metal thin film adjacent to the chelating agent layer, but also passes through the pinholes and cracks existing in the metal thin film and is adjacent to the upper surface side of the metal thin film, that is, the transparent resin layer. It is presumed that since it reaches the surface of the transparent resin layer and chelates the upper surface side, it imparts resistance to chemicals that pass through and penetrate the transparent resin layer. And as such a chelating agent, for example, gallic acid ester, stearoylbenzoylmethane, methylol amide, anthoranilic acid, benzotriazole, 2-meltcaptobenzothiazoher, behenic acid,
Quinoline, quinoline etiodide, o-tolylthiouric acid, p-tolylthiouric acid, propyl sulfide, diamylamine, formaldehyde, p-thiocresol and the like can be applied.

When the metal thin film is made of aluminum, gallic acid ester, stearoylbenzoylmethane, methylolamide or anthoranilic acid is preferable, and gallic acid ester is particularly preferable.

The chelating agent layer can be formed by dissolving or dispersing the chelating agent in a suitable solvent and coating and drying an appropriate amount. Then, a metal thin film is formed on the chelating agent layer, and at the same time, the surface of the metal thin film adjacent to the chelating agent is chelated and the upper surface of the metal thin film is also chelated through the pinholes of the metal thin film. Therefore, the chemical resistance of this metal thin film can be improved. Even if the surface of the metal thin film is chelated, the metal thin film as a whole maintains conductivity, so that image formation by discharge is possible.

On the other hand, when the amount of the chelating agent applied is less than the appropriate amount, chelating of the metal thin film is not sufficient, and scumming due to chemicals may occur.

The solvent for dissolving or dispersing the chelating agent is, for example, methyl ethyl ketone (ME
Well-known solvents such as K) and toluene can be used.

Next, in the above technical means, the metal thin film is electrically connected to the power source and can be discharged between the needle electrode and the metal thin film, and the metal thin film disappears due to this discharge, despite the chelation of the surface. Something, for example, aluminum,
Thin films of metals such as silver, copper, gold, zinc, magnesium can be used. In this case, it is desirable to have a thickness of 300 angstroms or more because it is necessary to maintain conductivity despite chelation of the surface, and it is necessary to have a thickness of 1000 angstroms or less because it needs to be eliminated by discharge breakdown. Is desirable. Such a metal thin film can be formed on the base sheet by a known vacuum deposition method or sputtering method.

Further, the color of the surface located on the metal thin film side differs from the color of this metal thin film in the above-mentioned base sheet, and the portion where the metal thin film partially disappears and the base sheet is exposed forms an image. Examples of the sheet include a synthetic resin sheet mixed with a coloring material such as a dye or a pigment. Also, a synthetic resin sheet having a colored layer on the surface on which the metal thin film is laminated can be used. As the synthetic resin sheet, for example, a polyester sheet such as a polyester sheet for prepaid cards, a polyvinyl chloride sheet, an acrylic sheet, a plastic sheet such as a polycarbonate sheet, or the like can be used.
It is also possible to use a plastic sheet having a magnetic recording layer containing magnetic powder. Examples of the coloring layer provided on the synthetic resin sheet include a coating film or a printing layer having a thickness of 1 to 5 μm, which is composed of a paint or printing ink colored with a dye or a pigment.

Regarding the transparent resin layer, for example, vinyl chloride resins such as polyvinyl chloride and vinyl chloride-vinyl acetate copolymer; styrene resins; polyurethane resins; polyethyl acrylate, polymethyl acrylate, etc. Acrylic resin homopolymer or copolymer resin; nitrocellulose; formed by coating and drying a transparent thermoplastic resin such as saturated polyester or butyral resin on the above chelating agent layer to a dry film thickness of 1 μm or less. You can Incidentally, instead of this transparent thermoplastic resin,
For example, a resin may be used in which a functional group that reacts with a cross-linking agent is bound to the ends of these thermoplastic resins and a resin having this functional group is reacted with a cross-linking agent such as isocyanate to cure.

Then, this discharge recording sheet can form a recorded image by a method similar to the conventional method. That is, the metal roll connected to the power source is brought into contact with the transparent resin layer to connect the metal thin film to the power source through this transparent resin layer, and the needle electrode disposed in proximity to the transparent resin layer is selectively energized. By doing so, discharge is caused between the needle electrode and the metal thin film, and as a result, the metal thin film at the discharged portion disappears and a recorded image is formed.

[0019]

According to such a technical means, since the chelating agent layer for chelating the metal thin film is provided between the base sheet and the metal thin film, the metal thin film can be formed with its conductive property maintained. Since both surfaces are chelated, the metal thin film is unlikely to be corroded by chemicals such as alkaline chemicals, and the metal thin film can be stabilized for a long period of time.

[0020]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a sectional view of the discharge recording sheet according to the embodiment.

Example 1 First, the magnetic recording layer 12 of the white polyester sheet 11 for a prepaid card having a thickness of 188 μm provided with the magnetic recording layer 12 containing magnetic powder.
A base sheet 1 was obtained by forming an ink layer 13 on the above by an gravure coating method using an ink in which 5 parts by weight of carbon black was mixed with 100 parts by weight of a polyester resin so that the dry film thickness was 2.0 μm. It was

Next, a gallic acid ester-based corrosion inhibitor (trade name: ADEKA ARCLS DH-72 manufactured by Asahi Denka Kogyo Co., Ltd.) is MEK / toluene = 1/1 on the ink layer 13.
The chelating agent solution mixture was dissolved in a solvent (10 wt%), dry weight and gravure coating so that 1.4 g / m ² to form a chelating agent layer 2, the chelating agent layer 2 was vacuum-deposited with aluminum to form a metal thin film 3 having a film thickness of 500 angstrom.

Next, an acrylic ink is coated on the metal thin film 3 so that its dry film thickness is 0.7 μm to form a transparent resin layer 4, and the sheet is cut into a card shape to form a discharge recording sheet. I asked.

With respect to the discharge recording sheet thus obtained, the surface of the transparent resin layer 4 is brought into contact with the metal roll connected to the electrode, while the needle electrode connected to the cathode is arranged in the vicinity of the transparent resin layer 4. While the electric discharge recording sheet was running, a voltage of -40 V was selectively applied to the needle electrode according to the signal to form a recorded image.

The discharge recording sheet on which the recorded image was formed in this manner was dipped in a 5 wt% aqueous solution of sodium carbonate, and the state in which the metal thin film 3 was dissolved by sodium carbonate was observed.
The time until the metal thin film 3 was completely dissolved and disappeared was measured.

The results are shown in Table 1.

Example 2 Example 1 was repeated except that the chelating agent layer 2 was formed by gravure coating using a chelating agent solution having a concentration of 5% by weight so that the dry weight was 0.9 g / m ^2. Is almost the same as. Table 1 shows the experimental results obtained by immersing the obtained discharge recording sheet in an aqueous sodium carbonate solution.

Example 3 Example 1 was repeated except that the chelating agent layer 2 was formed by gravure coating to a dry weight of 0.7 g / m ² using a chelating agent solution having a concentration of 2% by weight. Is almost the same as. Table 1 shows the experimental results obtained by immersing the obtained discharge recording sheet in an aqueous sodium carbonate solution.

Example 4 Example 1 was repeated except that the chelating agent layer 2 was formed by gravure coating using a chelating agent solution having a concentration of 1% by weight so that the dry weight was 0.6 g / m ^2. Is almost the same as. Table 1 shows the experimental results obtained by immersing the obtained discharge recording sheet in an aqueous sodium carbonate solution.

Comparative Example A discharge recording sheet was obtained in the same manner as in Example 1 except that the chelating agent layer was not formed and the metal thin film 3 was directly formed on the ink layer 13. Then, Table 1 shows the experimental results of the immersion in the sodium carbonate aqueous solution.

[0032]

[Table 1]

[Confirmation] As is clear from the results shown in Table 1, in the discharge recording sheets according to Examples 1 to 4 in which the chelating agent layer was formed, the comparison was made without the chelating agent layer. It was confirmed that the time until the metal thin film 3 was completely dissolved and disappeared was dramatically longer than that of the example, and the chemical resistance thereof was improved.

[0034]

According to the present invention, since both sides of the metal thin film are chelated while maintaining its conductivity, corrosion of the metal thin film by chemicals such as alkaline chemicals is unlikely to occur, and the metal thin film can be used for a long period of time. It is possible to achieve stability over a period of time.

Therefore, a clear, accurate and precise image can be stably formed even in the presence of chemicals, and the formed recorded image hardly deteriorates with time.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a discharge recording sheet according to the present invention.

FIG. 2 is an explanatory diagram at the time of discharge recording.

[Explanation of symbols]

 1 Base Sheet 11 Polyester Sheet 12 Magnetic Recording Layer 13 Ink Layer 2 Chelating Agent Layer 3 Metal Thin Film 4 Transparent Resin Layer

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

Claims (1)

[Claims] 1. A colored base sheet, a metal thin film and a transparent resin layer sequentially laminated on the base sheet, and between the needle electrode and the metal thin film arranged in proximity to the transparent resin layer. In a discharge recording sheet in which an electric discharge is caused to selectively destroy a metal thin film and an image is formed by the base sheet exposed from the destroyed site, chelation for chelating the metal thin film between the base sheet and the metal thin film. An electric discharge recording sheet having an agent layer.