JPH0789230A - Electric discharge breakdown recording medium - Google Patents

Abstract

(57) [Summary] [Object] To provide an electric discharge recording medium having uniform and clear printing, chemical resistance, and excellent storage stability. [Structure] A magnetic recording layer 3, an anchor layer 4, a metal thin film layer 5, and a protective layer 6 are sequentially laminated on a substrate, and the anchor layer 4 provided adjacent to the metal thin film layer 5 has a center line average roughness. By applying embossing to the unevenness of 0.3 to 1.0 μm, uniform unevenness can be obtained, the surface strength does not decrease, and uniform and clear printing can be performed. Further, since the anchor layer does not contain an additive for forming a mat, it has weather resistance such as storage stability and chemical resistance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge breakdown recording medium for recording information by removing a conductive metal thin film laminated on a base material by discharge breakdown, and more particularly to a discharge having an uneven surface. Destruction recording medium.

[0002]

2. Description of the Related Art In recent years, magnetic recording means, recording means using a semiconductor integrated circuit, optical recording means and the like have been used as means for recording information on media such as cards, securities, gift certificates, tickets and slips. Taking a card as an example, a cash card as a magnetic recording means, a magnetic card such as a credit card or a prepaid card, an IC card as a recording means using a semiconductor integrated circuit, an IC memory card, an optical card as an optical recording means, an infrared ray. Infrared reading cards and the like that utilize reflection or absorption of light have been developed, and a wide variety of cards have been provided.

By the way, in using a card, a medium having a function according to its use is used. For example, in the case of a prepaid card, a cash card, etc. which reads and writes information at any time, it is economical and easy to use. A magnetic card is selected. However, the recording by the magnetic recording / reproducing means has a drawback that the recorded information cannot be visually read without using a reading device. Therefore, it has been proposed to incorporate a special element other than magnetic recording. Taking the above-mentioned prepaid card as an example, a character or mark indicating the amount of money and the balance of the medium is previously formed on the magnetic recording medium by printing or the like. Every time, a method is used in which punched holes or marks are provided on the card according to the use of the prepaid card and the balance information is displayed. In this method, the information that can be displayed is limited, and the positions of the punch holes or marks are only a guide, so it is extremely difficult to display accurate information.

Therefore, as a method of visually displaying information, a heat-sensitive transfer recording method is used in which a heat-sensitive transfer material is used to transfer and record information on a medium, and a heat-sensitive recording material that develops or discolors or erases color by heat is used. Thermal recording method for thermal recording on medium, thermal recording method for thermal recording of information on medium by thermal destruction of low melting point metal thin film such as tin (Sn), electrical discharge of conductive metal thin film on medium for electrical discharge destruction of information A discharge breakdown recording method for recording has been proposed and put into practical use.

Among the above-mentioned recording methods for visibly recording information on a medium, the discharge breakdown recording method has an excellent function of high recording speed and high-precision printing, but discharges a conductive metal. From the principle of removing with energy, the recording head (recording needle) and the return electrode (earth electrode) are brought into contact with the surface of the protective layer of the discharge breakdown recording medium, that is, the conductive metal thin film is passed through the protective layer of the discharge breakdown recording medium. And an electric circuit is formed to record information.

However, the protective layer is generally made of an electrically insulating resin, and if such a resin is used, the electrical conductivity is hindered, and discharge, that is, earth return occurs on the return electrode side. Therefore, in order to secure electric conductivity, the protective layer has been made as thin as possible, but the thinning of the protective layer causes deterioration of the surface strength of the medium and metal corrosion / deterioration due to deterioration of chemical resistance. It had a problem of inviting.

On the other hand, a conductive material is added to the protective layer,
Although a method of increasing electrical resistance and increasing the resistance of the protective layer has been proposed, there is a case where the protective layer sparks due to discharge breakdown and molten resin adheres to the recording head (recording needle). A new problem occurs that the printing performance deteriorates.

To solve this problem, the surface of the medium is made uneven or matted so that a discharge phenomenon is likely to occur so that stable printing can be performed. In addition, since the metal thin film surface is matted, the metallic luster disappears and the printed surface becomes easier to read.

As the method of forming the uneven shape or the mat shape, since the magnetic fine particles constituting the magnetic recording layer are dispersed, the surface itself of the magnetic recording layer has random unevenness. By providing a metal thin film layer on the surface, the medium surface can be matted. However, since the metal thin film layer is directly affected by the dispersant and magnetic fine particles contained in the adjacent magnetic recording layer, there is also a problem of corrosion of the metal thin film layer, so that it is necessary to provide an anchor layer on the metal thin film layer. Has become. A common method is to add an inorganic filler such as carbon black, graphite, silicon oxide, and metal powder, which also serves as a coloring agent, or an organic filler such as an acrylic resin and a melamine resin, to the anchor layer provided on the metal thin film layer provided there. Has been done to.

[0010]

However, when a conductive material such as carbon black, graphite, silicon oxide, or metal powder is used for the anchor layer laminated on the metal thin film layer, the metal thin film layer and the anchor layer are not separated from each other. There is a problem that a potential difference is generated between them and the metal thin film layer is electrochemically corroded, and even if the filler has an electrically insulating property, voids are generated due to the dispersibility of the resin and the filler constituting the anchor layer. The barrier property is deteriorated, for example, a corrosive liquid or gas permeates through the voids, and there is a problem in weather resistance such as chemical resistance. Further, the addition of the filler makes it difficult to form uniform unevenness on the medium surface due to coating unevenness, filler unevenness, and the like, and unevenness of the printed surface causes defects such as uneven printing and unclear printing. Therefore, an object of the present invention is to provide an electric discharge recording medium which has effects of uniform and clear printing and excellent chemical resistance and storability.

[0011]

According to a first aspect of the present invention, there is provided a magnetic recording layer, an anchor layer, a metal thin film layer on a substrate,
In a discharge breakdown recording medium formed by sequentially stacking protective layers,
A discharge breakdown recording medium, characterized in that the anchor layer is formed by embossing into an uneven shape having a center line average roughness of 0.3 to 1.0 μm.

The invention described in claim 2 is an electric discharge breakdown recording medium characterized in that the metal thin film layer is made of aluminum.

According to a third aspect of the present invention, there is provided a discharge breakdown recording medium characterized in that a colored layer is provided between the magnetic recording layer and the anchor layer.

[0014]

According to the present invention, the anchor layer provided adjacent to the metal thin film layer is formed by embossing into a concavo-convex shape having a center line average roughness of 0.3 to 1.0 μm, whereby a uniform concavo-convex pattern is obtained. In addition, the surface strength is not reduced, and uniform and clear printing can be performed. Since the anchor layer does not contain an additive for matting, it has weather resistance such as chemical resistance.

[0015]

Embodiments of the present invention will be described in detail with reference to an embodiment of the drawings. FIG. 1 is an enlarged sectional view of a part of the discharge breakdown recording medium of the present invention, and FIG. 2 is an enlarged sectional view of a part of the discharge breakdown recording medium showing another embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes an electric discharge breakdown recording medium, which comprises a base material 2, a magnetic recording layer 3, an anchor layer 4 whose surface is embossed in an uneven shape, a metal thin film layer 5 having conductivity, and a protective layer 6. Composed. The base material 2 has a sheet shape, a plate shape, or a card shape, and is made of polyvinyl chloride, polyethylene, polyester, polypropylene, polyimide,
Plastics such as polycarbonate, polyethylene terephthalate, polystyrene, polymethylmethacrylate, ionomer, nylon and acrylic resin, paper such as paper, synthetic paper and synthetic paper can be used alone or in combination as a composite. The physical properties required for the base material are appropriately selected from the above materials according to the application such as strength, rigidity, hiding power, and light transmission.

The magnetic recording layer 3 is made of Fe, Co, Ni, γ-.
Fe₂O₃, Co deposition γ-Fe₂O ₃, Fe₃O_Four, F
e-Cr, Fe-Co, CrO₂, Co-Cr, Co-
Ni, MnAl, Ba ferrite, Sr ferrite, etc.
Fine particles made of a known magnetic material of
Resin, vinyl chloride / vinyl acetate copolymer resin,
Retin resin, polyester resin, cellulosic resin,
Kuryl resin, styrene-maleic acid copolymer resin, etc.
Mixture prepared by dispersing and mixing in resin or ink vehicle
A magnetic fine particle dispersion liquid consisting of
Knowledge roll coating method, knife edge method, gravure printing
Method, coating technology such as screen printing,
To achieve. Further, the magnetic recording layer 3 is provided as a transfer material.
Is also possible.

The anchor layer 4 is a polymer resin having adhesiveness to the magnetic recording layer 3 and the metal thin film layer 5, for example, a single resin or a copolymer resin such as polyester, polyurethane, epoxy resin, vinyl chloride resin, vinyl acetate resin or the like. Is used. As a forming method, an anchor layer 4 is provided on the magnetic recording layer 3, a stamper having a predetermined uneven surface is superposed on the surface, and the uneven surface is formed on the anchor layer 4 by embossing by heating and pressing.

If this uneven surface is too rough, the printing accuracy at the time of discharge breakdown recording will be reduced. If it is too small, the smoothness will increase, but for the above reasons, it will be difficult for discharge in the recording head to occur, printing will not be possible, stable printing will not be possible, and the surface gloss will be more likely to appear. As a result of confirmation by the inventors of the present invention that the recording becomes difficult to read, as a result of setting the surface to have a center line average roughness of 0.3 to 1.0 μm, good printing accuracy,
It was found that the printing surface was easy to read because the printing stability was obtained and the gloss was further reduced.

The thermoforming conditions for controlling the concavo-convex condition of the present invention have different appropriate values depending on the resin used for the anchor layer 4. Usually, heating in the range of 120 to 180 ° C. and 10 to 40 Kg / It is a pressure of cm ² .

If the thickness of the anchor layer 4 is other than the above, it may cause deterioration of the magnetic properties and obstruct the reproduction of the magnetic recording. If it is too thin, the magnetic recording layer 3 as described above may be used.
Since the metal thin film layer 5 may be corroded under the influence of an additive such as a dispersant contained in the above, it is preferable to set the thickness to about 0.5 to 4.0 μm in order to impart thermoformability. .

The metal thin film layer 5 is made of a conductive metal thin film which is conductive and can be destroyed and removed by electric discharge, and includes, for example, low melting point metals such as Al, Sn, Zn and Bi, alloys thereof and conductive metal compounds. Is used. In general, Al is desirable because it is easily destroyed by discharge and is costly. The metal thin film layer 5 may have a thickness of about 20 to 150 nm, and is preferably a thin film as long as it can shield the underlying layer. As a forming method, there are a vacuum vapor deposition method, a sputtering method, an ion plating method and the like.

The protective layer 6 is made of urethane resin, acrylic resin,
The well-known roll coating method, knife edge method, gravure printing method, screen printing method, etc., of a coating solution prepared by dissolving a resin such as vinyl chloride resin, polyester resin, nitrocellulose resin, styrene resin in a solvent such as toluene or xylene. It can be formed using a coating or printing technique. Further, if the protective layer 5 becomes thicker, the electrical conductivity will be sharply lowered, and it will be easy for an earth return to occur, and printing may not be possible. Further, if the thickness is reduced, the surface strength and the chemical resistance are lowered, so that the thickness is preferably about 0.3 to 2.0 μm. Further, in order to improve the surface strength, additives such as a lubricant and an abrasive can be added.

In the discharge breakdown recording medium 1 having the above structure, the underlying magnetic recording layer 3 is exposed through the anchor layer 4 by destroying and removing a part of the metal thin film layer 5 by electric discharge, and the metal thin film layer 5 is exposed. The print information can be read by the density difference between the surface and the non-printed portion. In order to make the printed surface easier to read, a colored layer 7 is provided between the magnetic recording layer 3 and the anchor layer 4 as in the discharge breakdown recording medium 10 of FIG. 2 to improve the printing density and change the printing color. Is possible.

The colored layer 7 is a commonly used polymer resin such as a polyester resin, an acrylic resin, a polyurethane resin, an epoxy resin, a vinyl chloride resin, a vinyl acetate resin, or another simple resin or a copolymer resin. Alternatively, a coating material to which a dye or a solvent is added is formed to a layer thickness of about 0.5 to 2.0 μm by using a well-known roll coating method, knife edge method, gravure printing method, screen printing method, or other coating or printing technique.

The discharge breakdown recording medium of the present invention will be described with reference to specific examples.

EXAMPLE 1 White polyethylene terephthalate having a thickness of 188 μm was used as a base material, and a magnetic paint having the following composition was applied on the upper surface of the base material by knife coating to about 1 μm.
A magnetic recording layer was prepared by applying the coating solution to a thickness of 0 μm, orienting the magnetic field in a horizontal magnetic field of about 3000 gauss, and then drying with hot air at 100 ° C. for about 3 minutes.

(Composition of magnetic paint) Magnetic powder (17500e, barium ferrite) 100 parts by weight Vinyl chloride-vinyl acetate copolymer 20 parts by weight Polyurethane resin 30 parts by weight Hexamethylene diisocyanate 2 parts by weight Dispersant (Garfuck RE- 610 Toho Chemical Co., Ltd.) 3 parts by weight Diluent Toluene 50 parts by weight MEK 50 parts by weight

Next, a resin paint having the following composition was gravure coated to form an anchor layer having a thickness of 2 μm.

(Composition of vapor deposition anchor varnish) Polyester urethane resin 30 parts by weight Diluent toluene 50 parts by weight MEK 50 parts by weight

The resulting anchor layer was embossed with a nickel stamper having irregularities with a centerline average roughness of 0.3 μm at a temperature of 160 ° C. and a heat pressure of 30 kg / cm ² to obtain the same centerline average as the stamper. Roughness 0.3μ
A surface roughness of m was transferred.

Next, the electrical resistance is 0.5Ω by the EB vapor deposition method.
An Al vapor-deposited film having a layer thickness of about 1000Å was formed to have a thickness of / □ to form a metal thin film layer.

Then, a protective resin varnish having the following composition was gravure-coated on the metal thin film layer to form a protective layer having a layer thickness of 0.8 μm to obtain a discharge breakdown recording medium of the present invention.

(Composition of protective resin varnish) Polyester (Byron 200, manufactured by Toyobo Co., Ltd.) 20 parts by weight Hexamethylene diisocyanate 5 parts by weight Polyethylene wax 2 diluent 60 parts by weight toluene 60 parts by weight MEK

Example 2 A nickel stamper having the center line average roughness of 0.5 μm on the surface of the anchor layer prepared in the same manner as in Example 1 was used, and 160 ° C., 30 Kg /
It performed embossed with heat and pressure in cm ^2, the surface roughness of the same center line average roughness 0.5μm stamper was transferred and formed. Thereafter, a discharge breakdown recording medium was produced in the same manner as in Example 1.

Example 3 A nickel stamper having the center line average roughness of 1.0 μm on the surface of the anchor layer prepared in the same manner as in Example 1 was used to obtain 160 ° C. and 30 kg / kg.
Embossing was performed by heating and pressing at a pressure of cm ² , and the same surface roughness as the center line average roughness 1.0 μm of the stamper was transferred and formed. Thereafter, a discharge breakdown recording medium was produced in the same manner as in Example 1.

COMPARATIVE EXAMPLE 1 A nickel stamper having irregularities was used for embossing by heating and pressurizing at 160 ° C. and 30 kg / cm ² , and the same center line average roughness as the stamper was 0.2 μm. Was transferred and formed. Thereafter, a discharge breakdown recording medium was produced in the same manner as in Example 1.

Comparative Example 2 A nickel stamper having the center line average roughness of 1.2 μm on the surface of the anchor layer prepared in the same manner as in Example 1 was used, and the temperature was 160 ° C. and 30 kg / kg.
Embossing was performed by heating and pressing at a pressure of cm ² , and the same surface roughness as the center line average roughness 1.2 μm of the stamper was transferred and formed. Thereafter, a discharge breakdown recording medium was produced in the same manner as in Example 1.

[Comparative Example 3] White polyethylene terephthalate having a thickness of 188 μm was used as a base material, and a magnetic paint having the following composition was applied on the upper surface of the base material by knife coating to about 1 μm.
After coating to a thickness of 0 μm and magnetic field orientation in a horizontal magnetic field of about 3000 gauss, it was dried with hot air at 100 ° C. for about 3 minutes to prepare a magnetic recording layer.

Magnetic powder (17500e, barium ferrite) 100 parts by weight Vinyl chloride-vinyl acetate copolymer 20 parts by weight Polyurethane resin 30 parts by weight Hexamethylene diisocyanate 2 parts by weight Dispersant (Garfuck RE-610 manufactured by Toho Chemical Co., Ltd.) 3 parts by weight Diluent Toluene 50 parts by weight MEK 50 parts by weight

Then, a resin coating having the following composition was gravure coated to form an anchor layer having a thickness of 2 μm.

(Composition of vapor deposition anchor varnish) Polyester urethane resin 30 parts by weight Silicon oxide (average particle size 0.5 μm) 6 parts by weight Diluent toluene 50 parts by weight MEK 50 parts by weight

Thereafter, the anchor layer was embossed in the same manner as in Example 1 to form a metal thin film layer and a protective layer to obtain a discharge breakdown recording medium.

Example 4 A black colored ink having the following composition was gravure coated on the magnetic recording layer prepared in Example 1 to form a colored layer having a layer thickness of 2 μm. [Example 4] (Composition of colored ink) Vinyl chloride-vinyl acetate copolymer 20 parts by weight Polyurethane resin 30 parts by weight Carbon black 7 parts by weight Diluent toluene 50 parts by weight MEK 50 parts by weight

Then, a resin coating having the following composition was gravure coated to form an anchor layer having a film thickness of 2 μm.

(Composition of vapor deposition anchor varnish) Polyester urethane resin 30 parts by weight Diluent toluene 50 parts by weight MEK 50 parts by weight

The obtained anchor layer was embossed with a nickel stamper having irregularities with a centerline average roughness of 0.5 μm at a temperature of 160 ° C. and a heat pressure of 30 kg / cm ² , and the same centerline average as the stamper was used. Roughness 0.5μ
A surface roughness of m was transferred.

Thereafter, a metal thin film layer and a protective layer were formed in the same manner as in Example 1 to obtain a discharge breakdown recording medium.

The discharge breakdown recording media described in the examples and comparative examples of the present invention were formed into cards, and discharge breakdown recording was performed by applying a voltage of -40V.
The presence / absence of earth return, print density, corrosiveness, etc. were evaluated, and the results are shown in Table 1.

[0050]

[Table 1]

* 1 Surface roughness of anchor layer: Center line average roughness μm * 2 Printing accuracy: Discharge occurs uniformly, the printed image is clear ... ◯: Discharge is slightly uneven Occurs, and the printed image is slightly unclear. △: The discharge is uneven, and the printed image is unclear.
・ ・ ・ ・ × * 3 Presence or absence of earth return: No occurrence of earth return ・ ・ ・ ・ ・ ・ ・ ○ Yes ・ ・ ・ ・ ・ ・ × × 4 Print density: With Macbeth reflection densitometer Measured density of printed area * 5 Non-printed density: Measured density of printed area by Macbeth reflection densitometer * 6 Corrosion: Observe the presence or absence of corrosion after soaking in 5% saline solution for 24 hours. No corrosion ・ ・ ○ Corrosion ・ ・×

From Table 1, it is confirmed that the surface roughness of the anchor layer is in the range of 0.3 to 1.0 μm when the properties such as print density, earth return and corrosiveness can be simultaneously satisfied. It can be seen that Comparative Example 3 in which an inorganic filler is added to the anchor layer to form a mat is inferior in printing accuracy and corrosiveness. As shown in Example 4, it was confirmed that the print density was improved by providing the black colored layer between the magnetic recording layer and the anchor layer.

[0053]

As described above, according to the present invention, the center line average roughness is 0.3 by embossing the anchor layer.
Since it is molded into a concave-convex shape of ~ 1.0 μm, it is possible to obtain clear print quality that is uniform and excellent in reproducibility with respect to the metal thin film layer, and does not cause printing defects such as earth return, and is an anchor layer. Since it does not contain an additive for matting, it is possible to provide a discharge breakdown recording medium excellent in storage stability and chemical resistance.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a part of a discharge breakdown recording medium of the present invention.

FIG. 2 is an enlarged sectional view of a part of a discharge breakdown recording medium showing another embodiment of the present invention.

[Explanation of symbols]

 1, 10 Discharge breakdown recording medium 2 Base material 3 Magnetic recording layer 4 Anchor layer 5 Metal thin film layer 6 Protective layer 7 Colored layer

Claims (3)

[Claims] 1. A discharge breakdown recording medium comprising a base material on which a magnetic recording layer, an anchor layer, a metal thin film layer, and a protective layer are sequentially laminated, and the anchor layer is embossed to have a center line average roughness of 0.3. A discharge breakdown recording medium characterized by being formed into a concavo-convex shape of ˜1.0 μm. 2. A discharge breakdown recording medium according to claim 1, wherein the metal thin film layer is made of aluminum. 3. The discharge breakdown recording medium according to claim 1, wherein a colored layer is provided between the magnetic recording layer and the anchor layer.