JP2946795B2 - Thermal transfer recording medium having conductive thin film layer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer recording medium for printing a conductive pattern such as an electric circuit using a heating recording medium such as a thermal head.

[0002]

2. Description of the Related Art In recent years, a thermal transfer recording system using a thermal head has rapidly spread. Various configurations have been proposed in which a layer containing a metal or a metal oxide is provided as a thermal transferable ink layer for the purpose of imparting metallic luster to a print pattern.

[0003] Such a layer is formed by dispersing a fine powder of a metal or metal oxide in a heat transferable resin and a metal or metal oxide by vacuum deposition or the like through a release layer on a substrate. However, in the former case, the transfer was not stable and a complete conductive pattern could not be formed. In the latter case, there is a problem that the conductivity is hindered by the presence of the coating layer interposed between the base material and the thin film.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional situation, and has a stable performance as a thermal transfer recording medium and a conductive pattern such as an electric circuit. An object of the present invention is to provide a thermal transfer recording medium that can be easily formed.

[0005]

In order to solve such a problem, the behavior of a thermal transfer recording medium having a metal thin film layer at the time of transfer was examined. If the layer is melted by the heat of printing, the melted coating film moves together with the metal thin film layer and covers the surface of the conductive pattern, which is inconvenient. In this case, it was not only technically difficult to form a film on the surface of a thin substrate, but also the It was found that there was a problem in adhesion, and it was not possible to exhibit stable performance as a thermal transfer recording medium.

[0006] It is well known that the adhesion between the base material and the metal thin film layer cannot be sufficiently obtained without the intervention of the coating film layer, which causes a problem in resolution in handling and printing of products. After examining the relationship between the surface properties of the material and the adhesion of the metal thin film layer and the resolution during thermal transfer, it was concluded that the above problem could be solved by roughening the surface of the base material. Obtained.

In this case, it has been found that the metallic luster on the surface of the print pattern is reduced, but it is very effective in terms of resolution and the like.

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view showing the structure of a thermal transfer recording medium having a conductive thin film layer according to the present invention. The conductive thin film layer (2) and the heat-adhesive resin layer (3) are provided on one side of a film-like substrate (1). Are formed in this order, and the film-shaped substrate (1)
Characterized in that at least one surface in contact with the conductive thin film layer (2) is roughened.

As the film-like substrate (1), a polyethylene terephthalate film is most suitable in terms of easy surface roughening and releasability from a metal thin film layer, and its thickness is 3 μm.
〜6 μm is preferred. Then, at least one surface is roughened, and the degree thereof is 1.0 μm in center line average roughness.
m to 2.5 μm. When the center line average roughness is 1.0 μm or less, adhesion to the conductive thin film layer (2) is insufficient, so that the conductive thin film layer is liable to peel off at the time of handling at room temperature and also to be printed. This causes a phenomenon in which the conductive thin film layer other than the image portion is peeled or transferred, which causes a reduction in resolution. On the other hand, when the thickness is 2.5 μm or more, it is impossible to form a uniform conductive thin film layer, and the sensitivity at the time of printing is remarkably reduced, so that the transfer of the conductive layer corresponding to an image becomes impossible.

The conductive thin film layer (2) is a continuous film of a conductive material such as a metal, for example, typically an aluminum layer formed by a vacuum deposition method, and has a thickness of 40.
The thickness is preferably in the range of 0 Å to 1000 Å. When the thickness is 400 Å or less, defects in conductivity are liable to occur.

The heat-adhesive resin layer (3) can be appropriately selected from thermoplastic resins, waxes and the like depending on the heat conditions at the time of printing and the properties of the material to be transferred. A thermoplastic resin such as a polyamide resin having a melting point of 60 to 90 ° C, and a carnauba wax having a melting point of 60 to 90 ° C.
Wax, such as candelilla wax, or a mixture thereof is used.

[0012]

When a conventionally used film having a smooth surface is used as a base material, the conductive thin film layer is peeled off during handling or transfer unless some resin layer is provided before forming the conductive thin film layer. However, if the surface of the film is roughened and a conductive thin film layer is formed thereon as in the present application, the above-mentioned disadvantages can be solved.

[0013]

Next, examples of a thermal transfer recording medium having a conductive thin film layer according to the present invention will be described.

The surface roughness on one side is the center line average roughness 1.7.
The thickness of 5.7 μm stretched polyethylene terephthalate film having a thickness of 5.7 μm was
A 00 angstrom aluminum layer is formed, and a 0.6 μm thick thermoadhesive resin layer made of an equal mixture of a polyamide resin having a softening point of 105 ° C. and carnauba wax is further formed thereon by a gravure printing method. A thermal transfer recording medium having the conductive thin film layer of the present invention was obtained.

As Comparative Example 1, a conductive thin film layer was provided in the same manner as in Example except that a stretched polyethylene terephthalate film having a thickness of 5.7 μm and a center line average roughness of the film surface of 0.6 μm was used. A thermal transfer recording medium was produced.

As a comparative example 2, the thickness of carnauba wax was 0.5 μm between the film and the aluminum layer.
A thermal transfer recording medium having a conductive thin film layer was produced in the same manner as in Comparative Example 1, except that a layer having a thickness of 0.5 μm and a layer of methyl methacrylate were formed.

Next, when a stripe pattern having a width of 10 mm and an interval of 1 mm was printed on a polyester film having a thickness of 180 μm using a line printer having a head density of 8 dot / mm, the thermal transfer recording medium of Example and the thermal transfer of Comparative Example 2 were printed. When the recording medium was used, a clear striped image was obtained. However, when the thermal transfer recording medium of Comparative Example 1 was used, the portions between the stripes were connected by the peeled metal layer, and the resolution was significantly reduced. From the continuous surface of each striped image, a terminal was contacted between two points separated by 30 mm, and the respective resistance values were measured. The thermal transfer recording medium of Example and the thermal transfer recording medium of Comparative Example 1 were measured. The value was 500Ω or less when used, but was 10MΩ or more when the thermal transfer recording medium of Comparative Example 2 was used.

[0018]

Since the thermal transfer recording medium of the present invention has the above-described structure, an arbitrary pattern having a metal surface exposed on the surface can be easily obtained, and electrical contact between the pattern surface and other conductors can be obtained. An electric circuit component without hindrance can be manufactured.
In addition, the conductive thin film layer does not fall off during handling of the thermal transfer recording medium, and storage stability and workability are good.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a thermal transfer recording medium of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Film-shaped base material 2 Conductive thin film layer 3 Thermal adhesive resin layer

Claims (3)

(57) [Claims] 1. A conductive thin film layer on one surface of a film-like substrate,
A thermal transfer recording medium having a thermally adhesive resin layer formed in this order, wherein at least one surface of the substrate is roughened. 2. The film-shaped substrate is a polyethylene terephthalate film, and the degree of surface roughening is 1.0 μm to 2.5 μm in center line average roughness.
A thermal transfer recording medium having the conductive thin film layer according to claim 1. 3. The method according to claim 1, wherein the conductive thin film layer is a metal layer formed by vapor deposition.
A thermal transfer recording medium having the conductive thin film layer according to any one of the above.