JPH0345391A - 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 an ionizing radiation cured resin layer on a base material film in a releasable manner. CONSTITUTION:An ionizing radiation cured resin layer 2 is provided on a base material film 1 in a releasable manner and formed from an ionizing radiation curable resin. This curable resin contains a polymer having a radical polymerizable double bond in its structure or an oligomer, for example, a monomer or polyfunctional monomer radical-polymerizable with (meth)acrylate of polyester, polyether, an acrylic resin, an epoxy resin or an urethane resin having a relatively low MW and further contains a photopolymerization initiator if necessary and is polymerized and crosslinked by electron beam or ultraviolet rays. A release layer lowers the adhesiveness of the ionizing radiation cured resin layer 2 and the base material film 1 to facilitate the transfer of the ionizing radiation cured resin layer and a rear layer 4 has action preventing the sticking of the thermal head of a printer.

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 thermal transfer cover film that can provide gloss.

(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 wax-type thermal transfer films, in which the thermal transfer layer softens when heated and is thermally transferred to the transfer material in the form of an image, and wax-type thermal transfer films, in which the dye in the thermal transfer layer is sublimated (heat-transferred) 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 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 wax type thermal transfer film, but these images have durability and 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 since the entire card is laminated, Curling may occur, and it is not possible to use very thin films due to laminating operations.
Therefore, there is a problem that the entire card becomes thick.

In addition, instead of the above laminating method, there is a method of applying and curing a thermosetting resin paint or an ionizing radiation-curable resin paint on the image surface, but these methods are not only complicated, but also cause the solvent in the paint to If a thermosetting resin is used, the heat during curing may cause the dye image to turn brown.

Therefore, the purpose of the present invention is to solve the problems of the prior art mentioned in 1., and to form an excellent image with excellent durability, especially abrasion resistance, gloss, color development, etc., and without curling, with a simple operation. An object of the present invention is to provide a thermal transfer cover 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 an ionizing radiation-cured resin layer is releasably provided on a base film.

(Function) By providing a peelable ionizing radiation-cured resin layer on the base film and transferring this ionizing radiation-cured resin layer to the surface of the transferred image, durability, especially abrasion resistance, and gloss can be improved with a simple operation. , it is possible to form an image with excellent color development and no curling.

In a particularly preferred embodiment, the ionizing radiation-curable resin layer contains a relatively large amount of transparent particles, so that the film can be easily cut during transfer, so that a protective layer with excellent abrasion resistance can be easily transferred. I can do it.

(Preferred Embodiments) The present invention will now 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. It is set in.

In addition, 3 in the figure is a peeling layer, which has the effect of lowering the adhesiveness between the ionizing radiation-cured resin layer and the base film to facilitate the transfer of the ionizing radiation-cured resin layer. This layer 3 is unnecessary if the peelability between the base film 1 and the ionizing radiation-cured 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 1 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.

Specific examples of preferable base films 1 include thin papers such as glassine paper, capacitor paper, and paraffin paper.Other examples include polyester, polypropylene, cellophane, polycarbonate, cellulose acetate, polyethylene, and polyvinyl chloride. 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 1 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 100 μm.

The ionizing radiation-curable resin layer 2 in the present invention is formed from an ionizing radiation-curable resin. The curable resin is a polymer or oligomer having a radically polymerizable double bond in its structure, such as a (meth)acrylate such as a relatively low molecular weight polyester, polyether, acrylic resin, epoxy resin, or urethane resin. It contains radically polymerizable monomers, polyfunctional monomers, etc., and if necessary, a photopolymerization initiator, and is polymerized and crosslinked by electron beams or ultraviolet rays. It can be used in the present invention and is not particularly limited.

Examples of radically polymerizable monomers include (meth)
Acrylic esters, (meth)acrylamides, allyl compounds, vinyl ethers, vinyl esters, vinyl heterocyclic compounds, N-vinyl compounds, styrene, (meth)
Examples of polyfunctional monomers include diethylene glycol di(meth)acrylate], triethylene glycol di(meth)acrylate, and tetraethylene glycol di(meth)acrylate. Acrylate, trimethylolpropane tri(meth)acrylate-1~, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, l.lis(β-(meth)acryloyloxyethyl)in cyanurate, etc. can be mentioned.

In the present invention, the ionizing radiation curable resin consisting of the above components is
If necessary, add an appropriate solvent or non-reactive transparent resin to adjust the viscosity, etc. to create an ink, and apply this to the base film, for example, by gravure coating, gravure reverse coating, roll coating. By applying, drying and curing by many other means, the ionizing radiation cured resin layer 2
form. The thickness of these cured resin layers is 0.5 to 2
A range of about 0 um is preferable.

Radiation such as ultraviolet rays or electron beams is used to cure the ionizing radiation-curable resin layer. Conventional techniques can be used as is for radiation irradiation, for example, in the case of electron beam curing, Kotscroft-Walton type, bump graph type, resonant transformer type, insulated core transformer type, linear type, electrocurtain type, dynamidron type, etc. An electron beam or the like having an energy of 50 to 1,0 OOKev, preferably 100 to 300 KeV, emitted from each fm electron beam accelerator such as a high frequency type is used. Ultraviolet rays emitted from light sources such as low-pressure mercury lamps, carbon arcs, xenon arcs, and metal halide lamps are used. Of course, the curing by ionizing radiation may be performed immediately after the formation of the curable resin layer or after the formation of all the layers.

1. When forming the ionizing radiation-cured resin layer, it is preferable to add a relatively large amount of highly transparent particles to the cured resin layer. These particles include inorganic particles such as silica, alumina, calcium carbonate, curcum, clay, etc., which are submicron to several LLm in size, and organic particles such as acrylic resin, polyester resin, melamine resin, and epoxy resin. It is preferable to use such highly transparent particles in an amount ranging from 10 to 200 parts by weight per 100 parts by weight of the ionizing radiation curable resin. If the amount used is too small, film breakage during transfer may be insufficient. On the other hand, if the amount is too high, the transparency as a protective layer will be insufficient, which is not preferable. Furthermore, by including other additives such as waxes, lubricants, ultraviolet absorbers, antioxidants, and/or optical brighteners, the smoothness, gloss, light fastness, etc. of various images to be coated can be improved. 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 ionizing radiation-cured resin layer. The peel & if layer is formed from a release agent such as wax, silicone wax, silicone resin, fluororesin, acrylic resin, or the like. The formation method may be the same as the formation method of the ionizing radiation-cured resin layer except for curing, and the thickness thereof is 0.5 to 5 μm.
It is enough. In addition, 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 is matt-treated. I can do it.

Furthermore, a heat-sensitive adhesive layer 5 may be provided on the surface of the above-mentioned ionizing radiation-cured resin layer in order to improve the transferability of these layers. These heat-sensitive adhesive layers are preferably formed by applying and drying a solution of a resin having good adhesive properties when heated, such as acrylic resin, vinyl chloride resin, vinyl chloride/vinyl acetate copolymer resin, polyester resin, etc. is formed to have a thickness of approximately 0.5 to 10 μm.

The above is the structure of the thermal transfer cover film of the present invention,
It goes without saying that the ionizing radiation-curable resin layer of such a cover film may be provided singly 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. In particular, 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 wax 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 wax type transfer image on a card base material made of polyester resin, vinyl chloride resin, etc. This is the image that was created. 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 superimposed on the surface of the card base material 6, and a yellow image 7Y is transferred by a thermal printer operating 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, the protective layer 2 is formed by transferring an ionizing radiation-cured resin layer onto the color image 7 and/or images 8 such as characters using the thermal transfer cover film of the present invention.

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. The printing energy may be appropriately adjusted in each case. 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, an ionizing radiation-cured resin layer is removably provided on a base film, and this ionizing radiation-cured resin layer is transferred to the surface of a transferred image, thereby allowing easy operation. It is possible to form an image that has excellent durability, particularly abrasion resistance, gloss, color development, etc., and does not cause curling.

In a particularly preferred embodiment, the ionizing radiation-curable resin layer contains a relatively large amount of transparent particles, so that the film can be easily cut during transfer, so that a protective layer with excellent abrasion resistance can be easily transferred. I can do it.

(Example) Next, the present invention will be described in more detail by giving reference examples, examples, usage examples, and comparative 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 (Macrol, ex, Yellow 6G
, manufactured by Bayer) 5.
5 parts Polyvinyl butyral resin (S-LEC BX-1゜Made by Tsukiki Kagaku) 4.5 parts Methyl ethyl ketone/]・Luene (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 63] 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 primer layer (thickness 0.5 μm thick) made of polyurethane resin was formed on the surface.
Yellow, magenta and cyan were applied to the surface of a 6.0 μm thick polynisdel film (trade name "Lumirror" manufactured by Toshiba Co., Ltd.) to form 2. A sublimation type thermal transfer sheet was prepared by repeatedly applying and drying the dye layer in a width of 15 cm in order to form three color sublimable dye layers.

Reference Example 2 The following wax ink composition was heated at a temperature of 100°C and coated in an amount of about 4 g on the same base film as Reference Example 1, but without a primer layer, using a hot melt roll coating method. /rn' wax type heat transfer sheet! ·It was created.

Wax ink ester wax 1G part oxidized wax 1G part paraffin wax 60 parts carbon black
12 Parts Example Work 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 (2).

Ink for release layer Silicone 1Δ4 resin 10 parts Vinyl chloride/vinyl acetate copolymer 10 parts Methyl ethyl ketone 100 parts Toluene
100 parts Next, the following ink was coated on the surface of the release layer at a ratio of Log/rn'' based on solid content and dried to form an ionizing radiation curable resin layer.

Ionizing discharge cotton layer ink Dipentaerythritol hexaacrylate 40 parts Hydrophobic colloidal silica 40 parts Polymethyl methacrylate 20 parts Polyethylene wax 3 parts Methyl ethyl carbon
250 parts toluene
250 parts Next, on the surface of the resin layer, an ink having the following composition is applied at a ratio of Ig/rn' based on solid content and dried to form an adhesive layer, and then an electron beam irradiation device manufactured by Nissin High Voltage Co., Ltd. in a nitrogen atmosphere of 10-7 Torr using
The ionizing radiation-curable resin layer was cured by irradiating an electron beam at 80 KV and a dose of 5 M r a d to produce a thermal transfer cover film of the present invention.

Vinyl chloride/vinyl acetate copolymer 10 parts Methyl ethyl ketone 100 parts Toluene
100 copies Example 2 A thermal transfer cover film of the present invention was prepared in the same manner as in Example 1 except that the following ink was used in place of the ionizing radiation-curable resin ink in Example 1.

Ionizing discharge ink for hardwood layers 60 parts of trimethylolpropane triacrylate 10 parts of talc (manufactured by Nippon Kuruku, Micro Ace L-1) 1/30 parts of polymethyl methacrylate (manufactured by Sumitomo 3M, Florard 432) )
3-part methyl ethyl ketone
200 parts toluene
Example of using 200 parts] Polyvinyl chloride containing about 10% of additives such as stabilizers (
100 parts of a compound (degree of polymerization: 800), 10 parts of a white pigment (ditane oxide), and a plasticizer (D).

P) A sublimable dye layer of the sublimation type thermal transfer film of Reference Example 1 is overlaid on the surface of a card base material consisting of 0.5 parts, and heat energy is applied using a thermal head connected to electrical signals obtained by color-separating facial photographs. was applied to form a full-color photographic image of the face, then letters and symbols were transferred and formed using the wax-type thermal transfer film of Reference Example 2, and furthermore, each image was formed using the thermal transfer cover film of the present invention of Example 1. A transferable protective layer was transferred to the image area to obtain a card with 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.
I created a card in the same way.

Comparative Example 1 A card was prepared in the same manner as in Use Example 1 except that the ionizing radiation-cured resin layer was not transferred in Use Example 1.

Comparative Example 2 A cover film was prepared in the same manner as in Example 1, except that the following ink was used instead of the ink for the ionizing radiation-curable resin layer in Example 1, and a card was prepared in the same manner as in Use Example 1.

Eishin Okisato Kounoma Polyester Resin (U-18, manufactured by Arayo Kagaku) 20 parts Methyl ethyl ketone 50 parts Toluene
50 copies Comparative Example 3 A cover film was created in the same manner as in Example 1, except that the following ink was used instead of the ink for the ionizing radiation-cured resin layer in Example 1, and a card was created in the same manner as in Use Example 1. did.

Cellulose resin (CAB381-0.1) 2
0 parts 0 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 ionizing radiation-cured resin layer is sharply cut in the image area.

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

Abrasion resistance: The image surface is rubbed 100 times with gauze impregnated with isopropyl alcohol.

0: No contamination of gauze.

○: Gauze is slightly contaminated.

×: Severe contamination of gauze.

Hikari Sawa Nigelos value%.

[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: Ionizing radiation curing resin layer 3: Peeling layer 4: Back layer 5: Adhesive layer 6: Card base 7: Color image 8: Characters, etc.

Claims (4)

[Claims] (1) A thermal transfer cover film characterized by having an ionizing radiation-cured resin layer releasably 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 ionizing radiation-cured resin layer. (3) The thermal transfer cover film according to claim 1, wherein the ionizing radiation-cured resin layer contains a relatively large amount of transparent particles. (4) The thermal transfer cover film according to claim 1, wherein the ionizing radiation-curable resin layer contains a wax, a lubricant, an ultraviolet absorber, an antioxidant, and/or a fluorescent brightener.