JP4830885B2 - Thermal transfer recording medium - Google Patents

Description

  The present invention relates to a thermal transfer recording medium, and more particularly to a backcoat layer of a thermal transfer recording medium, and more particularly to a thermal transfer recording medium that can contribute to improved durability and maintenance-free thermal heads.

  Conventionally, when printing an output print of a computer, word processor, facsimile or the like by a thermal transfer method, a recording material layer made of heat-melting ink or a recording material layer containing a sublimation dye is provided on one surface of a base film. A thermal transfer recording medium is used.

  Printing and image formation using such a thermal transfer recording medium are performed by superimposing a recording material layer and a transfer medium and heating the substrate film from the back with a thermal head.

  However, when a plastic film is used as the base film, the thermal head adheres to the base film during printing and the peeling from the thermal head and the slip property are impaired, or the base film breaks. There is a fear.

  For this reason, a back coat layer is formed on the back surface of the base film. As the back coat layer, a combination of a thermoplastic resin and a phosphate ester (for example, see Patent Document 1), or a combination of a binder resin and an anionic surfactant having a sodium sulfonate group (for example, a patent document). 2) and the like have been proposed.

The said prior art document is shown.
JP 61-95989 A

JP-A-6-99670

  However, the former is mainly intended to prevent sticking, and the latter is primarily intended to prevent thermal head wear and discharge breakdown, and there has been no thermal-sensitive transfer recording medium that is self-cleaning and is maintenance-free.

  The present invention has been made to solve the above-described problems relating to the thermal transfer recording medium, and it is an object of the present invention to provide a thermal transfer recording medium that is self-cleaning as well as the durability of a thermal head and is maintenance-free. And

The invention according to claim 1 of the present invention is the heat-sensitive transfer recording medium in which the heat-sensitive transfer layer is provided on one surface of the base film and the heat-resistant slip layer is provided on the other surface. Surfactant consisting of at least an alkane sulfonate sodium salt as a lubricant, mainly composed of a binder composed of a plastic resin, or a reaction product of a thermoplastic resin and a polyvalent isocyanate, or a radical reaction product triggered by ultraviolet rays or electron beams. And a filler having a Mohs hardness of 4 or less and a true specific gravity of 2.5 times that of the binder. The filler content in the heat-resistant slipping layer is 10 to 30% by weight. This is a thermal transfer recording medium.

Thus, according to the first aspect of the present invention, the heat-resistant slipping layer comprises a binder comprising a thermoplastic resin, a reaction product of a thermoplastic resin and a polyvalent isocyanate, or a radical reaction product triggered by ultraviolet rays or an electron beam. As a lubricant, it contains at least a surfactant composed of an alkane sulfonate sodium salt as a lubricant, and further contains a filler having a Mohs hardness of 4 or less and a true specific gravity of 1.8 times or more of the binder. The thermal head can be prevented from being worn, and a thermal transfer recording medium having self-cleaning properties can be obtained.
Furthermore, since the surfactant is made of alkane sulfonate sodium salt type, the durability of the thermal head is further improved from the electrical (static) aspect.

The invention of claim 2 is the thermal transfer recording medium according to the invention of claim 1 , wherein the filler in the heat resistant slipping layer is an inorganic mineral.

The invention of claim 3 is the thermal transfer recording medium according to claim 1 or 2 , wherein a reactive modified silicone oil is contained as a lubricant in the heat resistant slipping layer. .

Thus, according to the invention of claim 3, since the reactive silicone oil is used as the lubricant in the heat-resistant slipping layer, the amount of the lubricant component added can be reduced, the settling is reduced, and the transferability is improved. Increase sensitivity.

According to a fourth aspect of the present invention, in the first, second or third aspect of the invention, the thermal transfer layer is a thermal sublimation transfer layer comprising a heat sublimable dye and a binder. It is.

The invention of claim 5 is the invention of claim 1, 2, 3 or 4, wherein the thermal transfer layer, a feature that it is a heat-sensitive melt transfer layer comprising a dye or / and pigment and binder, It is a thermal transfer recording medium.

  As described above, by using the thermal transfer recording medium of the present invention, the thermal conduction unevenness from the thermal head is eliminated, and the thermal transfer recording medium sensitive to the thermal conduction unevenness can be applied. If there is uneven heat conduction, it becomes rough and appears in the print.

The present invention will be described in detail below based on one embodiment.
For example, as shown in FIG. 1, the thermal transfer recording medium (1) of the present invention has a thermal transfer layer (12) on one side of a substrate film (11) and a heat-resistant lubricant layer (13 on the other side). ), And a thermal head (not shown) is in contact with the heat-resistant lubricant layer (13).

  Examples of the base film (11) include various base films conventionally used for thermal transfer recording media. From the viewpoint of heat resistance, changes in mechanical properties, cost, etc., particularly polyethylene terephthalate film is used. It can be used suitably.

The heat-sensitive transfer layer (12) is a recording layer for characters, pictures, etc., and is a heat-sensitive melting type recording layer consisting of dyes, pigments, dyes and pigments, binders, etc. Any of the sublimation type recording layers may be used. Each is composed of a colorant and a binder, and various additives can be added as necessary.

  As the colorant, among organic or inorganic dyes or pigments, those having a color density required as a recording material and not discoloring or fading due to light, heat, temperature or the like are preferable. In addition to cyan, magenta, yellow, black, and the like, various colorants can be used as the colorant.

  Examples of the binder include a type mainly composed of wax and a type mainly composed of butyral resin. In any type, various additives can be added as necessary.

  The heat resistant lubricant layer (13) imparts heat resistance, slip property, self-cleaning property, etc. to the surface of the base film (11) that contacts the thermal head. Containing as a main component a binder composed of a reaction product of isocyanate or a radical reaction product triggered by ultraviolet rays or electron beams, and containing a surfactant composed of at least an alkane sulfonate sodium salt as a lubricant, and having a Mohs hardness of 4 or less The filler contains a filler whose true specific gravity is 1.8 times or more that of the binder.

  The binder used in the heat-resistant lubricant layer is preferably a butyral resin (true specific gravity 1.1), the polyvalent isocyanate is preferably tolylene diisocyanate, the filler is calcium carbonate (Mohs hardness 3, true specific gravity 2.7), mica (Mohs hardness 2.8, true specific gravity 2.9), gypsum (Mohs hardness 2, true specific gravity 3.0), talc (Mohs hardness 1, true specific gravity 2.8) and the like, the most preferred filler is talc It is.

  As a method for forming the heat-sensitive transfer layer (12) and the heat-resistant lubricant layer (13) on the base film (11), a known coating method such as a gravure coating method may be used.

Next, the present invention will be described in more detail with reference to examples.
First, a polyethylene terephthalate film having a thickness of 4.5 μm was prepared as a base film (11). Moreover, the coating solution which consists of the following compounding ratio was produced as [the coating liquid for thermal sublimation transfer layer formation] used for formation of a thermal transfer layer (12).

Magenta dye 20.0 parts Butyral resin 15.0 parts Polyester resin 5.0 parts Toluene 30.0 parts Methyl ethyl ketone 30.0 parts Furthermore, as [Coating liquid for forming a heat-sensitive melt transfer layer], a coating solution having the following blending ratio was used. Produced.

Magenta pigment 10.0 parts Epoxy resin 20.0 parts Carnauba wax 10.0 parts Toluene 30.0 parts Methyl ethyl ketone 30.0 parts

On one surface of the prepared base film (11), [Coating liquid-1 for forming a heat resistant slipping layer] according to the following formulation was applied by a gravure coating method so that the dry thickness was 0.8 μm.
[Coating solution-1 for forming a heat resistant slipping layer]
Butyral resin (true specific gravity 1.1) 5.0 parts Phosphate ester compound 0.8 parts Alkanesulfonate sodium salt compound 0.2 parts Calcium carbonate (Mohs hardness 3, true specific gravity 2.7) 4.0 parts Tri Range isocyanate 2.0 parts Toluene 43.0 parts Methyl ethyl ketone 45.0 parts The true specific gravity of the filler is about 2.5 times that of the binder. The filler content is about 33%.
Next, the prepared [thermal sublimation transfer layer forming coating solution] was applied to the other surface of the base film so as to have a dry thickness of 1.0 μm by the gravure coating method. A recording medium was produced.

On one surface of the prepared base film (11), [Coating fluid-2 for forming a heat resistant slipping layer] according to the following formulation was applied by a gravure coating method so that the dry thickness was 0.6 μm.
[Coating solution-2 for forming a heat resistant slipping layer]
Butyral resin (true specific gravity 1.1) 5.0 parts Phosphate ester compound 0.8 parts Alkane sulfonate sodium salt compound 0.2 parts Talc (Mohs hardness 1, true specific gravity 2.8) 1.0 part Tolylene Isocyanate 2.0 parts Toluene 45.0 parts Methyl ethyl ketone 46.0 parts The true specific gravity of the filler is about 2.5 times that of the binder. The filler content is about 11%.
Next, the prepared [thermosensitive transfer layer forming coating solution] was applied to the other surface of the base film so as to have a dry thickness of 1.0 μm by the gravure coating method. A recording medium was produced.

On one side of the prepared base film (11), [Coating liquid for forming a heat resistant slipping layer-3] according to the following formulation was applied by a gravure coating method so that the dry thickness was 0.6 μm.
[Coating liquid-3 for forming a heat resistant slipping layer]
Butyral resin (true specific gravity 1.1) 5.0 parts Alkanesulfonate sodium salt compound 0.2 part Amino-modified silicone oil 0.2 part Talc (Mohs hardness 1, true specific gravity 2.8) 1.0 part Tolylene Isocyanate 2.0 parts Toluene 45.8 parts Methyl ethyl ketone 45.8 parts The true specific gravity of the filler is about 2.5 times that of the binder. The filler content is about 12%.
Next, the prepared [thermosensitive transfer layer forming coating solution] was applied to the other surface of the base film so as to have a dry thickness of 1.0 μm by the gravure coating method. A recording medium was produced.

On one surface of the prepared base film (11), [Coating liquid for forming a heat resistant slipping layer-4] according to the following formulation was applied by a gravure coating method so that the dry thickness was 0.8 μm.
[Coating liquid for forming heat resistant slipping layer-4]
Butyral resin (true specific gravity 1.1) 5.0 parts Phosphate ester compound 0.8 parts Alkane sulfonate sodium salt compound 0.2 part Silicon powder (Mohs hardness 0.6, true specific gravity 1.3) 4.0 Part Tolylene diisocyanate 2.0 part Toluene 44.0 parts Methyl ethyl ketone 44.0 parts The true specific gravity of the filler is about 1.2 times that of the binder. The filler content is about 33%.
Next, the prepared [thermal sublimation transfer layer forming coating solution] was applied to the other surface of the base film so as to have a dry thickness of 1.0 μm by the gravure coating method. A recording medium was produced.

On one side of the prepared base film (11), [Coating liquid for forming a heat resistant slipping layer-5] according to the following formulation was applied by a gravure coating method so that the dry thickness was 0.8 μm.
[Coating liquid for forming heat resistant slipping layer-5]
Butyral resin (true specific gravity 1.1) 5.0 parts Phosphate ester compound 0.8 parts Alkanesulfonate sodium salt compound 0.2 parts Silicon powder (Mohs hardness 0.6, true specific gravity 1.3) 1.0 Part Tolylene diisocyanate 2.0 part Toluene 45.5 part Methyl ethyl ketone 45.5 part The true specific gravity of the filler is about 1.2 times that of the binder. The filler content is about 11%.
Next, the prepared [thermal sublimation transfer layer forming coating solution] was applied to the other surface of the base film so as to have a dry thickness of 1.0 μm by the gravure coating method. A recording medium was produced.

On one surface of the prepared base film (11), [Coating liquid for forming a heat-resistant slipping layer-6] according to the following formulation was applied by a gravure coating method so that the dry thickness was 0.6 μm.
[Coating liquid for forming heat resistant slipping layer-6]
Butyral resin (true specific gravity 1.1) 5.0 parts Alkanesulfonate sodium salt compound 0.2 part Amino-modified silicone oil 0.2 part Silica (Mohs hardness 7, true specific gravity 2.1) 1.0 part Tolylene Isocyanate 2.0 parts Toluene 45.8 parts Methyl ethyl ketone 45.8 parts The true specific gravity of the filler is about 1.9 times that of the binder. The filler content is about 12%.
Next, the prepared [thermally melted transfer layer forming coating solution] was applied to the other surface of the base film so as to have a dry thickness of 1.0 μm by a gravure coating method. A recording medium was produced.

Three types of thermal transfer recording media obtained in this manner (Examples 1 to 3) and three types of comparative examples (Examples 4 to 6, total 6 types) were prepared using a thermal simulator at 8 inches / inch.
s. A 10 km transfer test was carried out at a speed of 5 mm, and the state of the thermal head and photographic paper after the test was visually observed. The results are shown in Table 1. During the transfer test, the thermal head was not cleaned at all.

このように滑剤として反応性シリコーンオイルを使用することで、滑剤成分の添加量が少なくて済む。よって裏移りが減り、転写性が向上（＝感度アップ）する。

By using reactive silicone oil as a lubricant in this way, the amount of lubricant component added can be reduced. Therefore, the settling is reduced and the transferability is improved (= sensitivity is increased).

1 is a schematic cross-sectional explanatory view of a thermal transfer recording medium of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Thermal transfer storage medium 11 ... Base film 12 ... Thermal transfer layer 13 ... Heat-resistant lubricant layer

Claims (5)

In the thermal transfer recording medium in which the thermal transfer layer is provided on one side of the base film and the heat resistant slipping layer is provided on the other side,
The heat-resistant slipping layer is composed mainly of a binder composed of a thermoplastic resin, a reaction product of a thermoplastic resin and a polyvalent isocyanate, or a radical reaction product triggered by ultraviolet rays or an electron beam, and at least an alkane sulfonate as a lubricant. It contains a surfactant composed of a sodium salt type, further contains a filler having a Mohs hardness of 4 or less and a true specific gravity 2.5 times that of the binder, and the filler content in the heat-resistant slipping layer is 10-30. A thermal transfer recording medium, characterized in that the content is% by weight . 2. The thermal transfer recording medium according to claim 1, wherein the filler in the heat resistant slipping layer is made of an inorganic mineral. The thermal transfer recording medium according to claim 1, wherein a reactive modified silicone oil is contained as a lubricant in the heat resistant slipping layer. The thermal transfer layer, characterized in that a heat-sensitive sublimation transfer layer comprising a thermally sublimable dye and a binder, thermal transfer recording medium according to any one of claims 1 to 3. The thermal transfer recording medium according to any one of claims 1 to 4 , wherein the thermal transfer layer is a thermal fusion transfer layer comprising a dye or / and a pigment and a binder.

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