JPH04290787A - Discharge breakdown recording medium - Google Patents

Abstract

PURPOSE:To increase the adhesion between a recording layer and a protecting layer and improve the corrosion inhibitive properties of the recording layer to achieve superior durability and reliability by forming the recording layer of metal film on a substrate through a background layer and adding a resin having a functional group which bonds chemically with a metal to the protecting layer formed on the recording layer. CONSTITUTION:A recording layer 3 of metal film is provided on a substrate 1 through a background layer 2, and further, a protecting layer 4 is provided on the recording layer 3. After that, part of the recording layer 3 is broken down using an electric discharge to form holes. Thus a discharge breakdown recording medium on which data is printed and a resin having a functional group which bonds chemically with a metal is added to the protecting layer 4. In addition, a thermal plastic resin whose glass transition temperature is 100 deg.C or lower is added to the background layer 2, and the background layer 2 is formed using a coat containing a color pigment or is constituted with a coat 21 containing the color pigment and a transparent coat 22 laminated on the coat 21. The color pigment is a magnetic powder.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a discharge destruction recording material that prints by destroying a part of a recording layer made of a thin metal film provided on a substrate through an underlayer by electric discharge and making holes. More specifically, the present invention relates to a discharge destruction recording medium that has good durability, excellent reliability, and provides clear prints.

0002

[Prior Art] Printing and recording methods using metal thin films have conventionally been known as heat-sensitive recording methods in which printing is performed by heating a part of a heat-sensitive recording layer made of a thin film of a low-melting point metal to create melt holes, and metal thin films. There are discharge destruction recording methods that print by destroying a part of the recording layer made of a thin film by electric discharge and making holes.The recording medium used in these recording methods is disclosed in Japanese Patent Application Laid-Open No. 59-199284. A heat-sensitive recording material disclosed in Japanese Patent Publication No. 54-15416 and a discharge destruction recording material disclosed in Japanese Patent Publication No. 54-15416 have been proposed.

0003

[Problem to be solved by the invention] However, the thermal recording method cannot be rewritten and has excellent durability and stability over time, so it can be used when printing and displaying amounts, counts, dates, etc. Although it is used in various ways, the printing method is basically a thermal head method, which requires time for the head to cool down, so there is a limit to the printing speed, and it is difficult to perform high-speed processing at stations and supermarkets. Its use is severely restricted in fields that require it. In addition, the discharge destruction recording method is superior in that it cannot be rewritten and can print at higher speeds than the heat-sensitive recording method, but in principle, electricity is applied to the recording layer made of a thin metal film to melt it. Since printing is performed by scattering, it is not possible to form a thick protective layer made of an insulating resin layer on the recording layer. As a result, the protective function is insufficient, and sufficient barrier properties are not obtained against the infiltration of moisture, etc., and when exposed to high humidity environments, corrosion may occur, causing changes in appearance or falling off, or printing Parts may disappear or become unclear, making it impossible to record, making it less durable and less reliable than thermal recording methods. Furthermore, because the discharge breakdown of the recording layer occurs microscopically only in the energized parts of the printed dots, it is usually difficult to form complete printed dots, and for this reason, the printed density is not necessarily sufficient and clear. The disadvantage is that it is inferior to the thermal method in terms of obtaining accurate printing.

0004

[Means for Solving the Problems] The present invention has been made as a result of various studies in view of the current situation, and involves forming a recording layer made of a thin metal film on a substrate with an underlayer interposed therebetween, and further forming a recording layer on the recording layer. By incorporating a resin having a functional group that chemically bonds with metal into the protective layer of the discharge breakdown recording material, the adhesiveness between the recording layer and the protective layer is strengthened, and the corrosion resistance of the recording layer is improved. It has improved durability and reliability. Furthermore, by containing a thermoplastic resin with a glass transition temperature of 100°C or less in the underlayer, the recording layer is easily melted and scattered by Joule heat, and the printing density is improved, resulting in clear printing. It was made so that it could be obtained.

In the present invention, the protective layer formed on the recording layer made of a thin metal film preferably contains a resin having a functional group that chemically bonds with the metal. When contained in the protective layer, the functional groups in this resin chemically bond with the metal of the recording layer, resulting in strong adhesion between the recording layer and the protective layer. However,
Even if the thickness of the protective layer formed on this recording layer is thinner than that of the heat-sensitive recording method, it will not be corroded even if it does not have sufficient barrier properties against the intrusion of moisture. Corrosion resistance is improved even in corrosive atmospheres such as In particular, crevice corrosion due to moisture intrusion into the interface between the recording layer, which is made of a thin metal film, and the protective layer, which tends to occur at the edges of cards or sheets, is significantly suppressed, and the thickness of the protective layer is reduced. Even if it is thin, it can provide practically sufficient corrosion resistance. As a result, the thickness of the protective layer can be reduced and the electrical resistance does not increase, making it easy to conduct electricity to the recording layer and preventing deterioration in print quality.

[0006] As described above, silicone resins such as acrylic silicone resins, acrylic resins containing titanium, and the like are preferably used as resins having functional groups that chemically bond with metals to be contained in the protective layer. These resins are dissolved alone or together with various other thermoplastic resins and thermosetting resins in an organic solvent, and the protective layer coating obtained by this dissolution is applied onto the recording layer and dried. , a transparent protective layer is formed that is sufficiently transparent to light.

The thickness of such a protective layer is 0.5 μm in order to conduct electricity well through this protective layer to the recording layer immediately below the protective layer and to easily melt and scatter the recording layer.
It is preferable to make it less than m. However, generally 0
．． If it is thinner than 1 μm, it is difficult to function as a protective layer, so it is preferably 0.1 μm or more.

Furthermore, the lower the glass transition temperature and the lower the elastic modulus at high temperatures of the resin used, the lower the recording layer formed between the substrate and the recording layer made of a thin metal film. When the adhesive force with the recording layer decreases and the recording layer melts and scatters due to Joule heat, as the adhesive force decreases,
It becomes easier to scatter and print density improves. For this reason, it is preferable to contain a resin with a glass transition temperature of 100°C or less in the base layer, and the lower the glass transition temperature, the lower the glass transition temperature, the softer it will melt at a higher temperature, and the adhesive strength will be relatively lower. A remarkable effect can be obtained by using one whose temperature is 80°C or less. However, if a glass transition temperature lower than 30°C is used, durability such as storage stability will be impaired, so it is preferable that the glass transition temperature is higher than 30°C.

[0009] As a resin having a glass transition temperature of 100°C or less, thermoplastic resins are preferred because thermoplastic resins do not undergo cross-linking and hardening at the same time as they are melted by heating, and are sufficiently softened. Preferably, such resins include acrylic resin, polyvinyl butyral resin,
Examples include vinyl chloride-vinyl acetate copolymer, polyacetal resin, polyimide resin, thermoplastic polyurethane resin, and these may be used alone or in combination.

[0010] Formation of such an underlayer is carried out by dissolving the above-mentioned thermoplastic resin having a glass transition temperature of 100° C. or less in an organic solvent in combination with other resins, and forming the underlayer obtained by this dissolution. It is formed by applying a coating material onto a substrate and drying it.

At this time, in order to obtain high-contrast printing, the base layer should contain a colored pigment, or the base layer should consist of a coating film containing a colored pigment and a transparent resin layer laminated thereon. It is desirable to have a two-layer base layer.

[0012] In order to incorporate a colored pigment into the base layer, the colored pigment is mixed and dispersed in an organic solvent together with the above-mentioned thermoplastic resin having a glass transition temperature of 100°C or less and other resins if necessary. Prepare a base layer paint containing pigment,
The coating for the base layer is applied on the substrate and dried to form the base layer. In particular, the binder resin used in combination with the colored pigment is polyurethane resin, vinyl chloride-vinyl acetate copolymer. , and vinyl chloride resins having acrylic hydroxyl groups are preferably used.

The colored pigment must have a color that can be visually recognized between the recording layer made of a thin metal film, but from the viewpoint of contrast, black pigments are preferably used, and carbon black and other pigments are preferred. is preferably used. Further, a magnetic powder may be used as the colored pigment, and the underlayer may also serve as the magnetic recording layer.If the pigment is used also as the magnetic recording layer, not only coloring but also magnetic recording can be performed at the same time.

[0014] The thickness of such an underlayer varies depending on the type of material and forming method, but it is usually preferably 5 μm or less. However, in general, if the thickness is less than 0.2 μm, it is difficult to function as an underlayer, so 0.2 μm or less is less effective.
The thickness is preferably 2 μm or more.

The recording layer consisting of a thin metal film formed between such an underlayer and a protective layer is formed by vacuum evaporation, plating, sputtering, etc. of a metal material on the underlayer. As a material, it usually has good conductivity;
Aluminum is used because it has a high degree of whiteness and a good appearance, and also because it is easy to form a thin film and is suitable for mass production, but other metals such as silver and tin and various aluminum-based alloys are also used.

[0016] As the base material, conventionally used nylon, cellulose diacetate, cellulose triacetate, polystyrene, polyethylene, polypropylene, polyester, polyimide, polycarbonate, polyethylene terephthalate can be used. Plastic substrates such as polyethylene naphthalate are preferably used.

[0017] Such a discharge destruction recording medium of the present invention is as follows:
As shown in FIG. 1, on the substrate 1, a glass transition temperature of 10
It is formed by sequentially laminating a base layer 2 containing a thermoplastic resin having a temperature of 0° C. or less, a recording layer 3 consisting of a thin metal film, and a protective layer 4 containing a resin having a functional group that chemically bonds with metal. Using a discharge rupture printer equipped with a ground electrode 5 and a printing electrode 6, the metal of the recording layer 4 is melted and scattered to open the hole 7, which is about three times as large as in the case of a normal thermal recording method. High-speed printing is performed.

[0018]

[Example] Next, an example of the present invention will be described. Example 1 Barium ferrite magnetic powder (average particle size 0
．． 8 μm) 80 parts by weight Acrylic hydroxyl group-containing vinyl chloride-vinyl acetate copolymer
10 〃 (U.C.C.
manufactured by VAGH) Polyurethane resin (manufactured by Dainippon Ink & Chemicals Co., Ltd.; Pande 7
〃X T5201) Trifunctional polyisocyanate compound (Japan Polyurethane 1〃 Kogyo Co., Ltd.; Coronate L) Carbon black

4 〃
toluene

260 Cyclohexanone

260 This composition was mixed and dispersed in a ball mill for 100 hours to prepare a magnetic paint, and this magnetic paint was applied to a polyethylene terephthalate film with a thickness of 188 μm.
A black magnetic layer having a thickness of 15 μm was formed by coating and drying on a sheet by a gravure method.

[0019] Next, on the black magnetic layer, a base layer paint made by dissolving polyvinyl butyral resin with a glass transition temperature of 50°C in a mixed solvent of toluene and cyclohexanone was applied to a thickness of 2.5 μm using a gravure method. It was applied and dried to form a base layer.

Next, using an EBX-6 type resistance heating evaporation apparatus manufactured by ULBAC, the base layer was coated without heating.
Vacuum level: 1 x 105 Torr, deposition rate: 50 Å/sec
Then, aluminum was vacuum-deposited to form a recording layer having a thickness of 500 Å made of a thin metal film of aluminum on the underlayer.

[0021] Next, a protective layer paint in which an acrylic silicone resin (manufactured by Chisso Corporation; Cycolate), which is a copolymerization of an acrylic resin and a silane compound, is dissolved in xylene is applied onto the recording layer, and dried to a thickness of 0. A protective layer made of acrylic silicone resin with a thickness of 4 μm is formed, and a magnetic layer 21, an underlayer 22, a recording layer 3, and a protective layer 4 are sequentially laminated on the polyethylene terephthalate sheet 1 as shown in FIG. We created a record of discharge breakdown.

Example 2 The same procedure was carried out as in Example 1 except that polymethyl methacrylate having a glass transition temperature of 110°C was used instead of polyvinyl butyral resin having a glass transition temperature of 50°C. A base layer was formed in the same manner as in Example 1, and a discharge breakdown recording material was produced.

Example 3 Same as Example 1, except that a thermosetting polyurethane resin with a glass transition temperature of 50°C was used in place of the polyvinyl butyral resin with a glass transition temperature of 50°C in the formation of the base layer in Example 1. A base layer was formed in the same manner as in 1, and a discharge breakdown recording material was produced.

Example 4 The same procedure as in Example 1 was carried out except that an acrylic resin with a glass transition temperature of 90°C was used in place of the polyvinyl butyral resin with a glass transition temperature of 50°C in the formation of the base layer in Example 1. An underlayer was formed using the following methods, and a discharge breakdown recording material was produced.

Comparative Example 1 A protective layer was formed in the same manner as in Example 1, except that acrylic resin was used instead of acrylic silicone resin (manufactured by Chisso Corporation; Cycolate). We then created a discharge breakdown record.

Comparative Example 2 A protective layer was formed in the same manner as in Example 2, except that acrylic resin was used instead of acrylic silicone resin (manufactured by Chisso Corporation; Cycolate). We then created a discharge breakdown record.

Comparative Example 3 A protective layer was formed in the same manner as in Example 3, except that acrylic resin was used instead of acrylic silicone resin (manufactured by Chisso Corporation; Cycolate). We then created a discharge breakdown record.

Comparative Example 4 A protective layer was formed in the same manner as in Example 4, except that acrylic resin was used instead of acrylic silicone resin (manufactured by Chisso Corporation; Cycolate). We then created a discharge breakdown record.

[0029] The discharge destruction recording materials obtained in each example and comparative example were printed at a printing speed of 150 mm/sec using a discharge destruction printer head with a dot density of 8 lines/mm and a size of 1 dot of 120 x 120 μm. to check the print density. The print density was measured by so-called reflection density measurement, and the reflection density was measured using a Macbeth RD915 type densitometer on a 5 mm square print area, and the average density including the unfused area between each dot was determined. Furthermore, the durability of the discharge breakdown recording bodies obtained in each of the Examples and Comparative Examples was tested. The durability test was carried out by leaving each of the obtained discharge breakdown recording bodies in an atmosphere of 60° C. and 90% RH for 10 days, and observing changes in appearance, fading of printed parts, etc. For comparison, a heat-sensitive melt printing type recording medium using Sn was simultaneously tested and designated as Comparative Example 5. In addition, the print density is 0.7 to 1 (○) for those with a print density of 1 or more.
Those within the range of 1 were evaluated as (△), and those that were 0.7 or less were evaluated as (×). Table 1 below shows the results.

[0030]

[0031]

[Effects of the Invention] As is clear from Table 1 above, the discharge destruction recording materials obtained by the present invention all have high printing density and have no change in appearance compared to conventional discharge destruction recording materials and heat-sensitive recording materials. In addition, there is no discoloration of the printed portion, and therefore, the discharge destruction recording material obtained by this invention has clear printing.
It can be seen that the corrosion resistance is sufficiently improved, and the durability and reliability are sufficiently improved.

[0032]

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram illustrating the principle of printing on a discharge destruction recording medium using a discharge destruction printer.

FIG. 2 is an enlarged sectional view of a main part of an embodiment of the discharge destruction recording material obtained by the present invention.

[Explanation of symbols]

1 Base 2 Base layer 21 Magnetic layer (colored base layer) 22 Base layer (transparent base layer) 3 Recording layer 4 Protective layer 7 holes

Claims (5)

[Claims] [Claim 1] A recording layer made of a thin metal film is provided on a substrate via an underlayer, a protective layer is further provided on the recording layer, and a part of the recording layer is destroyed by electric discharge to form a hole. A discharge breakdown recording material for printing, characterized in that a protective layer contains a resin having a functional group that chemically bonds with a metal. 2. The discharge breakdown recording material according to claim 1, wherein the underlayer further contains a thermoplastic resin having a glass transition temperature of 100° C. or less. 3. The discharge breakdown recording material according to claim 1 or 2, wherein the base layer is a base layer formed of a coating film containing a colored pigment. 4. The discharge breakdown recording material according to claim 1, wherein the base layer is composed of a two-layer coating film, a coating film containing a colored pigment and a transparent coating film laminated thereon. Claim 5: Claim 3 wherein the colored pigment is a magnetic powder.
and discharge breakdown recording material according to 4.