JPH0569657A - 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-shaped electrode and a metal thin film 2 which are composed of a base sheet 1, a metal thin film 2 and a transparent resin layer 3 and are arranged in close proximity to each other.
Is a discharge recording sheet for forming an image by destroying the metal thin film 2 by discharge between the transparent resin layer 3 and a chelating agent such as gallic acid ester for chelating the metal thin film 2. Characterized by And
Since the surface of the metal thin film 2 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 is less likely to deteriorate with time. have.

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. Assuming that the discharge recording sheet has a structure in which an electric discharge is caused between the needle electrode and the metal thin film disposed in close proximity to selectively destroy the metal thin film, and an image is formed by the base sheet exposed from the destroyed site, The resin layer contains a chelating agent for chelating the metal thin film.

In such technical means, the chelating agent contained in the transparent resin layer is one which chelates the surface of the metal thin film to improve resistance to chemicals such as alkaline chemicals, 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.

As the transparent resin forming the transparent resin layer containing the chelating agent, for example, polyvinyl chloride,
Vinyl chloride resin such as vinyl chloride-vinyl acetate copolymer; styrene resin; polyurethane resin; homopolymer or copolymer resin of acrylic resin such as polyethyl acrylate and polymethyl acrylate; nitrocellulose; saturated polyester, butyral resin A transparent thermoplastic resin such as can be applied. Incidentally, instead of this transparent thermoplastic resin, for example,
You may use the resin hardened by making the functional group which reacts with a crosslinking agent couple | bond with the terminal of these thermoplastic resins, and making the resin which has this functional group and a crosslinking agent, such as isocyanate, react.

A chelating agent is added to the transparent resin in an amount of 1% by weight or more, preferably 2% by weight or more, and the chelating agent is dissolved or dispersed in a solvent to form a dry film thickness of 1 μm or less on the metal thin film. The transparent resin layer can be formed by coating and drying to remove the solvent.
Since the surface of the metal thin film is chelated at the same time as the transparent resin layer is dried by heating, the chemical resistance of the metal thin film can be improved. In this case, even if the surface of the metal thin film is chelated, since the metal thin film as a whole maintains conductivity, it is possible to form an image by discharge.

On the other hand, in the above technical means, the metal thin film is electrically connected to a power source and can be discharged between a needle electrode and the metal thin film disappears due to this discharge, despite chelation of the surface. 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 above-mentioned base sheet is one in which the color of the surface adjacent to the metal thin film is different from the color of this metal thin film, and the portion where the metal thin film partially disappears and the base sheet is exposed forms an image. For example, a synthetic resin sheet mixed with a coloring material such as a dye or a pigment may be used. Also,
It is also possible to use a synthetic resin sheet having a colored layer provided on the surface on which the metal thin film is laminated. 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, and a magnetic recording layer containing magnetic powder can be used. It is also possible to use the plastic sheet which it has. 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.

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.

[0017]

According to such technical means, since the chelating agent for chelating the metal thin film is contained in the transparent resin layer, the surface of the metal thin film is chelated while keeping its conductivity. Therefore, 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.

[0018]

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, aluminum was vacuum-deposited on the surface of the ink layer 13 of the base sheet 1 to form a metal thin film 2 having a film thickness of 500 angstrom.

Next, a gallic acid ester-based corrosion inhibitor (Asahi Denka Kogyo Co., Ltd.) was added to 100 parts by weight of the acrylic resin.
The above-mentioned metal thin film 2 is an acrylic ink formed by mixing and dispersing 10 parts by weight of ADEKA ARKULUS DH-72)
The transparent resin layer 3 was formed by coating the dried resin layer so that the dry film thickness was 0.7 μm, and cut into a card shape to obtain a discharge recording sheet.

With respect to the discharge recording sheet thus obtained, the surface of the transparent resin layer 3 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 3. 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 was immersed in a 5% by weight aqueous solution of sodium carbonate, and the state in which the metal thin film 2 was dissolved by sodium carbonate was observed.
The time until the metal thin film 2 was completely dissolved and disappeared was measured.

The results are shown in Table 1.

[Example 2] The same as Example 1 except that the transparent resin layer 3 was formed using an acrylic ink containing 5 parts by weight of the gallic acid ester-based corrosion inhibitor.

Table 1 shows the experimental results obtained by immersing the obtained discharge recording sheet in an aqueous sodium carbonate solution.

[Example 3] The same as Example 1 except that the transparent resin layer 3 was formed using an acrylic ink containing 2 parts by weight of the gallic acid ester-based corrosion inhibitor.

Table 1 shows the experimental results obtained by immersing the obtained discharge recording sheet in an aqueous solution of sodium carbonate.

[Example 4] The same as Example 1 except that the transparent resin layer 3 was formed by using an acrylic ink containing 1 part by weight of the gallic acid ester-based corrosion inhibitor.

Table 1 shows the experimental results of immersing the obtained discharge recording sheet in an aqueous sodium carbonate solution.

[Embodiment 5] This embodiment is substantially the same as Embodiment 1 except that the transparent resin layer 3 is formed using an acrylic ink containing 0.5 part by weight of the gallic acid ester-based corrosion inhibitor.

Table 1 shows the experimental results obtained by immersing the obtained discharge recording sheet in an aqueous sodium carbonate solution.

[Comparative Example] The procedure is substantially the same as in Example 1 except that the transparent resin layer is formed by using an acrylic ink in which the gallic acid ester-based corrosion inhibitor is not mixed.

Table 1 shows the experimental results obtained by immersing the obtained discharge recording sheet in an aqueous solution of sodium carbonate.

[0036]

[Table 1]

[Confirmation] As is clear from the results shown in Table 1, in the discharge recording sheets according to Examples 1 to 5 in which the transparent resin layer 3 containing the chelating agent was formed, the transparent resin layer had a chelate. It was confirmed that the time until the metal thin film 2 was completely dissolved and disappeared was drastically increased and the chemical resistance thereof was improved as compared with the comparative example containing no agent.

[0038]

According to the present invention, since the surface of the metal thin film is chelated while maintaining its conductivity, corrosion of the metal thin film due to 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, even in the presence of chemicals, a clear, accurate and precise image can be stably formed, 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 Metal Thin Film 3 Transparent Resin Layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tsutomu Kakubo 1-5-1 Taito, Taito-ku, Tokyo Within Toppan Printing Co., Ltd. No. 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, the transparent resin layer contains a chelating agent for chelating the metal thin film. A discharge recording sheet characterized in that