JPH0345396A - Thermal transfer cover film - Google Patents

Abstract

PURPOSE:To form an image excellent in durability, abrasion resistance, gloss and color forming properties and generating no curl by providing a wax containing transparent resin layer on a base material film in a releasable manner and transferring said transparent resin layer to the surface of a transfer image. CONSTITUTION:A wax-containing transparent resin layer 2 is provided on a base material film 1 in a releasable manner and formed from a mixture of a transparent resin and wax. A release layer 3 has action lowering the adhesiveness of the transparent resin layer 2 and the base material film 1 to facilitate the transfer of the transfer resin layer. In forming the transparent resin layer, additives such as a lubricant, an ultraviolet absorber, an oxidation inhibitor and/or a fluorescent brightener or the like are contained in the transparent resin layer. By this method, the gloss, light fastness, weatherability or whiteness of a coated image of every kind can be enhanced.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a thermal transfer cover film, and more specifically, it provides thermal transfer images with excellent durability such as abrasion resistance, and furthermore, provides thermal transfer images with excellent color development and This invention relates to a heat transfer cover film that can be glossy.

(Prior Art and its Problems) Conventionally, thermal transfer methods have come to be widely used as a simple printing method. These thermal transfer methods allow various types of images to be easily formed, and are therefore being used to produce printed matter that requires a relatively small number of prints, for example, for the production of ID cards such as identification cards.

If a color image is preferred, such as a photograph of a face, a large number of colored thermal transfer layers of, for example, yellow, magenta, and cyan (and black if necessary) are repeatedly provided in sequence on a continuous base film. A thermal transfer method using a long thermal transfer film has been used.

These thermal transfer films can be roughly divided into so-called melt transfer type thermal transfer films, in which the thermal transfer layer is softened by heating and thermally transferred in image form to the thermal transfer material, and thermal transfer films in which the dye in the thermal transfer layer is sublimated by heating. It is broadly classified into so-called sublimation type thermal transfer film, in which only the dye is thermally transferred in the form of an image onto the thermal transfer material.

When creating ID cards such as identification cards using the above thermal transfer film, it is easy to form images such as letters and numbers with the melt transfer type thermal transfer film, but these images are not durable. In particular, it has the disadvantage of poor abrasion resistance.

On the other hand, in the case of sublimation transfer type thermal transfer film, it is possible to form gradation images such as facial photographs, but unlike normal printing ink, the formed image does not have a vehicle, so the image has a glossy appearance. Furthermore, for the same reason, there is a problem that durability such as abrasion resistance is poor.

A method to solve these problems is to laminate a transparent film on the formed image surface, but this method is complicated to operate and requires lamination on the entire card. It is not possible to use a film that is too thin as it may curl or cause further lamination operations.
Therefore, there is a problem that the entire laminated card becomes thick.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, and to form a thermal transfer cover that has excellent durability, particularly abrasion resistance, gloss, color development, etc., and can form an excellent image without curling with simple operation. The purpose is to provide film.

(Means for solving problems) The above objects are achieved by the present invention as described below.

That is, the present invention is a thermal transfer cover film characterized in that a wax-containing transparent resin layer is removably provided on a base film.

(Function) When a wax-containing transparent resin layer is removably provided on a base film and this transparent resin layer is transferred to the surface of a transferred image,
The transparent resin layer is easily transferred onto the image by heat during printing, so it can be easily operated to improve durability, especially abrasion resistance, gloss, and
It is possible to form an image with excellent color development and no curling.

(Preferred Embodiments) Next, the present invention will be described in more detail with reference to the accompanying drawings that schematically show preferred embodiments.

FIG. 1 is a diagram schematically showing a cross section of a thermal transfer cover film according to a preferred embodiment of the present invention, in which a wax-containing transparent resin layer 2 is removable on a base film. It is set in.

In addition, 3 in the figure is a peeling layer, which has the effect of lowering the adhesiveness between the transparent resin layer and the base film to facilitate transfer of the transparent resin layer. This layer 3 is unnecessary if the peelability between the base film and the transparent resin layer is excellent.

Further, 4 is a back layer, which has the function of preventing the thermal head of the printer from sticking. This layer 4 is also unnecessary if the base film has good heat resistance and slip properties.

Next, the thermal transfer cover film of the present invention will be explained in more detail using the materials used, the forming method, etc.

As the base film (2) used in the present invention, the same base film used in conventional thermal transfer films can be used as is, and other films can also be used, and there are no particular limitations.

As specific examples of preferable base film 1, thin paper such as glassine paper, capacitor paper, and paraffin paper is useful, and in addition, for example, polyester, polypropylene, cellophane, polycarbonate, cellulose acetate, polyethylene, and polyvinyl chloride are useful. Examples include plastics such as polystyrene, nylon, polyimide, polyvinylidene chloride, and ionomer, and base films made of composites of these and procore paper.

The thickness of this base film (2) can be changed as appropriate depending on the material so that its strength, heat resistance, etc. are appropriate, but the thickness is preferably 3 to 1100 Ii.

The transparent resin layer 2 provided on the base film is formed from a mixture of transparent resin and wax.

Examples of the transparent resin include polyester resin, polystyrene resin, acrylic resin, epoxy resin, cellulose resin, polyvinyl acecool resin, vinyl chloride/vinyl acetate copolymer resin, and the like. Although these resins have excellent transparency, they tend to form relatively tough films, so
Since the film does not break sufficiently during transfer and has insufficient lubricity, it is easily scratched by surface friction and the surface gloss is likely to decrease. In the present invention, by mixing wax with these transparent resins, film breakage and smoothness during transfer are improved.

Representative examples of the wax used in the present invention include microcrystalline wax, carnauba wax, paraffin wax, and the like. In addition, Fischer-Tropsch wax, various low molecular weight polyethylenes, wood wax, beeswax,
Various waxes such as spermaceti wax, privet wax, wool wax, shellac wax, candelilla wax, petrolactam, partially modified wax, fatty acid ester, and fatty acid amide are used.

The amount of the wax used is preferably in the range of 0.5 to 20 parts by weight per 100 parts by weight of the transparent resin. If the amount of wax used is too small, the film may break during transfer and the abrasion resistance of the transferred film may deteriorate. On the other hand, if it is too large, the durability and transparency of the transfer film will become insufficient, which is not preferable.

The method of mixing the transparent resin and wax is not particularly limited, and may be a method of melting and mixing the two, or a method of dissolving and mixing the two in an appropriate organic solvent that dissolves them.

Particularly preferably, the transparent resin is used as a dispersion (or emulsion), while the wax is used as a solution or dispersion (emulsion).
It is preferable to use it as a compound and mix the two. After coating a base film using such a dispersion (emulsion), it is dried at a relatively low temperature to form a film so that at least a portion of these resin particles remain. The surface of the film thus formed is rough and partially cloudy due to residual resin particles, but the surface becomes smooth due to heat and pressure during thermal transfer, and can be transferred as a transparent film.

The transparent resin layer 2 can be formed on the base film 1 or on the release layer 3 previously provided on the base film 1 by applying an ink made of the above resin and wax by gravure coating, gravure reverse coating, roll coating, or many other methods. Examples include methods of coating and drying. When the transparent resin layer is formed from a mixed dispersion of resin and wax, drying after coating is carried out at a temperature below the melting point of the resin particles, for example 50 to 10
It is preferable to carry out the reaction at a relatively low temperature of about 0'C. By drying at such a temperature, the film is formed with the resin particles remaining, so that film breakage during transfer is significantly improved and the lubricity of the transferred film is maintained.

In addition, when forming the transparent resin layer, additives such as a lubricant, an ultraviolet absorber, an antioxidant, and/or a fluorescent whitening agent may be added to the transparent resin layer to improve the gloss of various images to be coated. , light resistance, weather resistance, whiteness, etc. can be improved.

It is preferable to form a release layer 3 on the surface of the base film prior to forming the transparent resin layer. Such a release layer is formed from a release agent such as the waxes described above, silicone wax, silicone resin, fluororesin, acrylic resin, or the like. The formation method may be the same as the method for forming the transparent resin layer, and a thickness of about 0.5 to 5 LLm is sufficient. If a matte protective layer is desired after transfer, the surface can be made matte by incorporating various particles into the release layer or by using a base film whose surface on the release layer side has been matt treated. You can also do it.

Furthermore, a heat-sensitive adhesive layer 5 can be provided on the surface of the above-mentioned transparent resin layer in order to improve the transferability of these layers. These heat-sensitive adhesive layers are made of, for example, acrylic resin,
Vinyl chloride resin, vinyl chloride/vinyl acetate copolymer resin,
Preferably 0.5
It is formed to have a thickness of about 10 μm.

The above is the structure of the thermal transfer cover film of the present invention,
It goes without saying that the transparent resin layer of such a cover film may be provided alone on the base film, or may be provided surface sequentially with the sublimation dye layer or the wax ink layer.

The image to be protected using the thermal transfer cover film as described above is preferably an image formed by a sublimation type thermal transfer method and/or a wax type thermal transfer method, but is not limited to these images. Especially when applied to sublimation transfer images, a protective layer is formed for the image, and the dye forming the image is recolored by the heat during transfer, making the image even clearer. There is.

Further, the sublimation transfer image and/or the melt transfer type transfer image may be formed on any transfer material, but in the present invention, it is preferable to form the sublimation transfer image and/or the melt transfer type transfer image on a card base material made of polyester resin, vinyl chloride resin, etc. This is the formed image. Of course, these card base materials include embossing, signatures,
An IC memory, a magnetic layer, other printing, etc. may be provided, and it is also possible to provide an embossing, a signature, a magnetic layer, etc. after the cover film is transferred.

An example of manufacturing a card using the thermal transfer cover film of the present invention will be described with reference to FIG. 2.

First, a yellow dye layer of a sublimation type thermal transfer sheet is placed on the surface of the card base material 6, and a yellow image 7Y is transferred by a thermal blink operated according to color separation signals. Similarly, a magenta image 7M and a cyan image 7C are transferred to the same area to form a desired color image 7. Next, desired characters, symbols, etc. 8 are similarly printed using a wax ink type thermal transfer sheet. Furthermore, a transparent resin layer is transferred onto the color image 7 and/or image 8 such as characters using the thermal transfer cover film of the present invention to form a protective layer 2. In this way, a desired card can be obtained.

For the above transfer, the thermal printer may be set separately (preferably consecutively) for sublimation transfer, wax ink transfer, and thermal transfer cover film, or
These transfers may be performed using a common printer by appropriately adjusting the printing energy. Incidentally, in the present invention, the heating means is not limited to a thermal printer, but it goes without saying that a geothermal plate, a hot roll, an iron, etc. may also be used.

(Effects) According to the present invention as described above, when a wax-containing transparent resin layer is removably provided on a base film and this transparent resin layer is transferred to the surface of a transferred image, the transparent resin layer will be able to absorb heat during printing. Since it is easily transferred onto an image, it is possible to form an excellent image with excellent durability, especially abrasion resistance, gloss, color development, etc., and which does not cause curling, with a simple operation.

(Example) Next, the present invention will be explained in more detail by giving reference examples, examples, and usage examples. In the text, parts or percentages are based on weight unless otherwise specified.

Reference example 1 An ink containing sublimable dyes of three colors having the following composition was prepared.

Yellow ink Disperse dye (Macrolex Yellow 6G, manufactured by Bayer AG) 5.5 parts Polyvinyl butyral resin (S-LEC BX-1゜Made by Tsukushiki Kagaku) 4.5 parts Methyl ethyl ketone/toluene (weight ratio 1/1) 89.0 parts Magenta ink Magenta disperse dye (Disperse Re
Same as yellow ink except that d60) was used.

Cyan disperse dye (Solvent Blue) is used as cyan ink dye.
Same as yellow ink except that 631 was used.

A heat-resistant slip layer (thickness: 1 μm) was formed on the back surface using the above ink composition by gravure coating, and a brimer layer (thickness: 0.5 μm) made of polyurethane resin was formed on the surface.
Yellow, magenta and cyan were applied to the surface of a 6.0 μm thick polyester film (trade name: Lumirror, manufactured by Toshi ■) to form a layer (m), in the order of yellow, magenta and cyan, respectively, so that the coating amount was approximately 3 g/m2. Three color sublimable dye layers were formed by repeatedly applying and drying the dye in a width of 15 cm in order to form a sublimation type thermal transfer sheet.

Reference Example 2 The following wax ink composition was heated at a temperature of 100°C and coated on the same base film as in Example 1, but without a brimer layer, by a hot melt roll coating method to a coating amount of about 4. g/rn" to prepare a melt transfer type thermal transfer sheet.

Wax ink acrylic/vinyl chloride/vinyl acetate copolymer resin
20 parts carbon black
10 parts toluene
35 parts methyl ethyl ketone 35
Section Example 1 An ink having the following composition was coated on the same base film as in Reference Example 2 at a ratio of Ig/m' based on solid content by a gravure coating method and dried to form a release layer.

Ink for release layer Acrylic resin 20 parts Methyl ethiketone 100 parts L.Luene
100 parts Next, the following ink was coated on the surface of the release layer at a ratio of 3 g/Tn2 based on solid content and dried to form a transparent resin layer.

Transparent FUiM layer Ink Acrylic resin 20 parts Polyethylene wax 1 part Methyl ethyl ketone
50 parts toluene
50 parts Next, an ink having the following composition was coated on the surface of the above resin layer at a ratio of Ig/rrj'' based on solid content and dried to form an adhesive layer to create a thermal transfer cover film of the present invention. .

Acrylic resin 10 parts Vinyl chloride/vinyl acetate copolymer 10 parts Methyl ethyl ketone toluene 100 parts Example 2 The following ink was used as the ink for the transparent resin layer of Example 1, and the others were as in Example A thermal transfer cover film of the present invention was prepared in the same manner as in Example 1.

Aqueous acrylic resin emulsion (solid content 30%)
20 parts paraffin wax aqueous emulsion (30% solids)
3 parts water
20 parts isopropyl alcohol
10 parts (drying was carried out at 50 to 55°C) Usage example 1 Polyvinyl chloride containing about 10% of additives such as stabilizers (
Degree of polymerization 800) 100 parts of compound, white face 1'4
A sublimable dye layer of the sublimation type thermal transfer film of Reference Example 1 was overlaid on the surface of a card base material consisting of 10 parts of titanium oxide (titanium oxide) and 0.5 parts of a plasticizer (DOF'). A full-color photographic image of the face is formed by applying thermal energy with a thermal head connected to an electrical signal, and then characters and symbols are transferred and formed using the melt-transfer type thermal transfer film of Reference Example 2, and then A transferable protective layer was transferred to each image portion using the thermal transfer cover film of the present invention in No. 1 to obtain a card having a facial photograph and various necessary information.

Usage Example 2 The thermal transfer cover film of Example 2 was used, and the others were the same as Usage Example 1.
processed in the same way.

Comparative Example 1 The same procedure as in Use Example 1 was carried out except that the transparent resin layer was not transferred.

Comparative Example 2 A cover film was produced in the same manner as in Example 1, except that the following ink was used as the ink for the transparent resin layer in Example 1, and a card was produced in the same manner as in Use Example 1.

Acrylic resin 21 parts Methyl ethyl ketone 50 parts Toluene
The cards obtained in 50 copies or more were evaluated and the results shown in Table 1 below were obtained.

Film breakage: Peelability of the film after transfer and microscopic observation of the transferred image.

0: Peeling is very easy, and the transparent resin layer is sharply cut as shown in the image.

○: There is some resistance to peeling, and the edges of the transparent resin layer are slightly disordered.

×: There is resistance to peeling, and the edges of the transparent resin layer are disordered.

9. Rub resistance: Rub the surface of the two images 100 times with gauze impregnated with isopropyl alcohol.

0: No contamination of gauze.

×: Severe contamination of gauze.

Gloss: The image was rubbed 100 times with synthetic paper and the change in gloss (gloss value %) was measured.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating a cross-section of a thermal transfer cover film of the present invention, and FIG. 2 is a diagram illustrating a cross-section of a card made using the above-mentioned cover film. 1: Base film 2: Transparent resin layer 3: Release layer
4: Back layer 5: Adhesive layer 6: Card base material 7: Color image 8: Characters, etc. 0

Claims (5)

[Claims] (1) A thermal transfer cover film characterized in that a wax-containing transparent resin layer is removably provided on a base film. (2) The thermal transfer cover film according to claim 1, wherein a release layer is provided between the base film and the transparent resin layer. (3) The thermal transfer cover film according to claim 1, wherein the transparent resin layer is formed from a mixed dispersion of a transparent resin and wax. (4) The thermal transfer cover film according to claim 1, wherein the transparent resin layer contains a lubricant, an ultraviolet absorber, an antioxidant, and/or a fluorescent brightener. (5) Wax content is 0.5 per 100 parts by weight of resin
The thermal transfer cover film according to claim 1, wherein the amount ranges from 20 parts by weight.