JP3314056B2 - Method for forming protective 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 method for forming a protective layer, and more particularly to a method for forming a protective layer capable of imparting excellent durability such as friction resistance, chemical resistance and solvent resistance to a thermal transfer image or the like. .

[0002]

2. Description of the Related Art Conventionally, a thermal transfer method has been widely used as a simple printing method. In these thermal transfer methods, since various images are easily formed, the printed matter which can be printed in a relatively small number of sheets, for example, an I.D.
It is used to create D cards.

[0003] When a color image such as a face photograph is preferable, a continuous base film is formed on a continuous base film, for example, yellow, magenta and cyan (and black if necessary).
A thermal transfer method using a long thermal transfer film in which a large number of colored thermal transfer layers are repeatedly provided face-to-face.

[0004]

The heat transfer film is roughly classified into a so-called fusion transfer type heat transfer film in which the heat transfer layer is softened by heating and thermally transferred to the heat transfer material in an image form. Accordingly, the dye in the thermal transfer layer is sublimated (thermally transferred), and only the dye is thermally transferred onto the heat transfer material in an image-like manner. When an ID card such as an identification card is made with the above-described heat transfer film, and when a heat transfer film of the fusion transfer type is used, it is easy to form images such as characters and numerals, but these images are durable. In particular, there is a disadvantage that the friction resistance is poor.

On the other hand, in the case of a sublimation transfer type thermal transfer film, a gradation image such as a photograph of a face can be formed. Inferior durability such as friction, furthermore, when it comes into contact with a card case containing a plasticizer, a file sheet, a plastic eraser, etc., the dye is transferred to these,
There is also a problem that chemical resistance such as blurring of an image and solvent resistance are poor.

As a method of solving such a problem, a method of laminating a transparent film on the formed image surface has been performed. However, this method is complicated in operation, and curls the image sheet. Also, there is a problem that a film that is too thin cannot be used in the operation of lamination, and therefore the entire laminated image sheet becomes thick.

As a method of solving the above problem, the present inventor has previously proposed a method of transferring a transparent resin layer only to an image surface. However, in this case, there is no problem when the transfer is performed by a hot stamper, but when the transfer is performed by a thermal head used for image formation, there occurs a problem that sufficient transfer and foil cutting are not performed.

Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art, and to achieve excellent durability, especially abrasion resistance, chemical resistance, solvent resistance and the like, without using a hot stamper and using only a thermal head. An object of the present invention is to provide a method for forming a protective layer on which an image can be formed.

[0009]

The above object is achieved by the present invention described below. That is, in the present invention, a transparent resin layer is provided on a base film in a releasable manner, and furthermore, an average
Polyvinyl chloride, polyvinyl acetate with a degree of polymerization of 50 to 300
And vinyl chloride / vinyl acetate copolymer
A heat transfer cover film provided with a heat-sensitive adhesive layer made of a resin having a glass transition temperature of 40 to 75 ° C. is superimposed on the surface of the transfer-receiving member with the adhesive layer facing the same, and the heat transfer cover film is placed on the base film side of the heat transfer cover film. Heating, transferring and adhering the transparent resin layer of the heated portion to a transfer object, and peeling off the transparent resin layer other than the heated portion from the transfer object together with a base film. I will provide a.

By forming the heat-sensitive adhesive layer provided on the surface of the transparent resin layer from a resin having a specific degree of polymerization and having a Tg of 40 to 75 ° C., the transparent resin layer is easily cut by a thermal head so that the foil is easily cut. Can be transferred to Therefore, since the transparent resin layer is easily transferred onto the image by the heat of the thermal head, an image having excellent durability, especially excellent friction resistance, chemical resistance, solvent resistance, etc. can be obtained by a simple operation.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described more specifically with reference to the accompanying drawings, which schematically show preferred embodiments. FIG. 1 is a view schematically showing a cross section of a thermal transfer cover film according to a preferred embodiment used in the present invention. In the thermal transfer cover film of this embodiment, a transparent resin layer 2 can be peeled off on a base film 1. And a heat-sensitive adhesive layer 5 thereon. Incidentally, reference numeral 3 in the drawing denotes a release layer, which has an effect of reducing the adhesiveness between the transparent resin layer and the base film to facilitate the transfer of the transparent resin layer. This layer 3 is unnecessary when the releasability between the base film and the transparent resin layer is excellent. Reference numeral 4 denotes a back layer, which has a function of preventing the thermal head of the printer from sticking.
This layer 4 is also unnecessary when the heat resistance and the slip property of the base film are good.

Next, the thermal transfer cover film used in the present invention will be described in more detail according to the materials used, the forming method and the like. As the substrate film 1 used in the present invention, the same substrate film as used in the conventional thermal transfer film can be used as it is, and other materials can also be used, and there is no particular limitation.

As a specific example of the preferred base film 1, for example, thin paper such as glassine paper, condenser paper, paraffin paper, etc. is useful. In addition, for example, polyester, polypropylene, cellophane, polycarbonate,
Examples thereof include plastics such as cellulose acetate, polyethylene, polyvinyl chloride, polystyrene, nylon, polyimide, polyvinylidene chloride, and ionomer, and a base film in which these are combined with the paper. The thickness of the base film 1 can be appropriately changed depending on the material so that the strength and heat resistance are appropriate.
Its thickness is preferably between 3 and 100 μm.

A transparent resin layer 2 provided on the base film
Are various resins excellent in friction resistance, chemical resistance, transparency, hardness, etc., for example, polyester resin, polystyrene resin, acrylic resin, polyurethane resin, acrylic urethane resin, silicone-modified resin of these resins and these. A mixture of each resin and the like can be mentioned. These resins are excellent in transparency, but tend to form a relatively tough film, so the film breakage at the time of transfer cannot be said to be sufficient.Therefore, silica, alumina, calcium carbonate, Highly transparent fine particles such as plastic pigment, wax, or the like may be added to such an extent that the transparency of the resin is not impaired.

The method of forming the transparent resin layer 2 on the base film 1 or on the release layer 3 previously provided on the base film 1 is as follows.
A gravure coat, a gravure reverse coat, a roll coat, a method of applying and drying an ink containing the above resin by various means, and the like can be mentioned. The thickness of the transparent resin layer 2 is preferably about 0.1 to 20 μm.

In forming the transparent resin layer, a lubricant, an ultraviolet absorber, an antioxidant and / or
Or by containing an additive such as a fluorescent whitening agent,
Scratch resistance, gloss, light resistance,
Weather resistance, whiteness and the like can be improved.

Prior to the formation of the transparent resin layer, the release layer 3, which may be formed on the surface of the base film, comprises waxes,
It is formed from a release agent such as silicone wax, silicone resin, fluorine resin, and acrylic resin. The forming method may be the same as the method for forming the transparent resin layer, and the thickness is 0.05 to
About 5 μm is sufficient. If a matte protective layer is desired after the transfer, a matte surface may be formed by including various particles in the release layer or by using a base film having the release layer side surface matted. You can also.

Further, a heat-sensitive adhesive layer 5 is provided on the surface of the transparent resin layer in order to improve the transferability of these layers. These heat-sensitive adhesive layers have an average degree of polymerization of 50 to 30.
0 polyvinyl chloride, polyvinyl acetate and vinyl chloride /
Tg of 40 selected from the group consisting of vinyl acetate copolymers
To 75 ° C., by more preferably for coating and drying the thermoplastic resins of the solution of Tg = 60 to 70 ° C., preferably formed to a thickness of about 0.1 to 10 [mu] m.

If the Tg of the heat-sensitive adhesive layer is less than 40 ° C., not only the adhesion between the image to be coated and the transparent resin layer is insufficient, but also the formed image is used at a relatively high temperature. In this case, the adhesive layer is softened to cause fine cracks in the transparent resin layer, and as a result, the chemical resistance, particularly the plasticizer resistance, becomes poor. On the other hand, if the Tg exceeds 75 ° C., the transferability of the transparent protective layer is insufficient by heating with a thermal head, and the foil cutting property of the transparent resin layer is reduced, making it difficult to perform transfer with good resolution.

Particularly preferred among the above-mentioned heat-sensitive adhesives are polyvinyl chloride resins having a polymerization degree of 50 to 250,
It is a polyvinyl acetate resin or a vinyl chloride / vinyl acetate copolymer resin, and has the same disadvantages as when the degree of polymerization is less than 50 and the Tg is low. On the other hand, when the degree of polymerization exceeds 300, the T
The same disadvantages as when g is high occur. The above is the configuration of the thermal transfer cover film used in the present invention.The transparent resin layer of such a thermal transfer cover film may be provided alone on the base film, or may be in the order of the sublimation dye layer or the wax ink layer. Of course, it may be provided.

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,
Since the protective layer of the image is formed and the dye forming the image is subjected to a recoloring process by the heat at the time of transfer,
This has the effect of making the image clearer.

The sublimation transfer image and / or the melt transfer type transfer image may be formed on any material to be transferred. In the present invention, particularly preferred are polyester resins and vinyl chloride resins. It is an image formed on a card base material. Of course, these card base materials may be provided with an emboss, sign, IC memory, magnetic layer, other printing, or the like, or may be provided with an emboss, sign, magnetic layer, etc. after transfer of the cover film. is there.

An example of manufacturing a card using the thermal transfer cover film will be described with reference to FIG. First, the yellow dye layer of the sublimation type thermal transfer sheet is superimposed on the surface of the card base material 6, and the yellow image 7Y is transferred by a thermal printer operating according to a color separation signal. 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 and the like 8 are similarly printed using a wax ink type thermal transfer sheet.
When the sublimation type thermal transfer area and the fusion type thermal transfer area are different, a sublimation image may be formed after transferring the wax ink. Further, the protective layer 2 is formed by transferring the transparent resin layer onto the color image 7 and / or the image 8 such as a character using the thermal transfer cover film. Thus, a desired card is obtained.

In the above transfer, the thermal printer may be set separately (preferably continuously) for sublimation transfer, wax ink transfer, and heat transfer cover film. The printing energy may be appropriately adjusted by a common printer. still,
In the present invention, the heating means is not limited to a thermal printer, but may be a hot plate, a hot roll, an iron, or the like.

[0025]

EXAMPLES Next, the present invention will be described more specifically with reference to Reference Examples and Examples. In the description, parts and% are based on weight unless otherwise specified. Reference Example 1 An ink containing three sublimable dyes having the following composition was prepared. Yellow ink disperse dye (Macrolex Yellow 6G, manufactured by Bayer AG) 5.5 parts Polyvinyl butyral resin (ESREC BX-1, manufactured by Sekisui Chemical) 4.5 parts Methyl ethyl ketone / toluene (weight ratio 1/1) 89.0 parts

The same as the yellow ink except that a magenta disperse dye (Disperse Red 60) was used as the magenta ink dye. Same as yellow ink except that cyan disperse dye (Solvent Blue 63) was used as cyan ink dye.

A heat-resistant slip layer (thickness: 1 μm) is formed on the back surface of the above ink composition by a gravure coating method.
A 6.0 μm thick polyester film (trade name “Lumirror” Toray Industries, Inc.) having a primer layer (0.5 μm thick) made of a polyurethane resin formed on the surface.
On a surface of yellow, magenta and cyan in order of yellow so that the coating amount is about 3 g / m ^2.
cm and repeatedly dried to form a sublimable dye layer of three colors, thereby producing a sublimation type thermal transfer sheet.

REFERENCE EXAMPLE 2 The following wax ink composition was heated at a temperature of 100 ° C., and coated by a hot melt roll coating method on the same base film as in Reference Example 1, but without the primer layer. Was applied so as to be about 4 g / m ² to prepare a heat transfer sheet of a fusion transfer type. Wax ink acrylic / vinyl chloride / vinyl acetate copolymer resin 20 parts Carbon black 10 parts Toluene 35 parts Methyl ethyl ketone 35 parts

REFERENCE EXAMPLE 3 An ink having the following composition was applied to the same base film as in Reference Example 2 at a ratio of 1 g / m ^{2 on} a solid content basis and dried to form a transparent resin layer. Ink for transparent resin layer Acrylic silicone graft resin (XSA-100, manufactured by Toa Gosei) 60 parts Methyl ethyl ketone 20 parts Toluene 20 parts

Next, an ink having the following composition is applied on the surface of the resin layer at a ratio of 0.7 g / m ^{2 on} a solid basis and dried to form an adhesive layer, and the thermal transfer used in the present invention is formed. A cover film was created. Ink for adhesive layer Vinyl chloride / vinyl acetate copolymer (VY
LF, manufactured by UCC, Tg = 68 ° C, polymerization degree 220) 30 parts Micro silica 0.4 part Methyl ethyl ketone 35 parts Toluene 35 parts

Reference Example 4 Except that a vinyl chloride / vinyl acetate copolymer (Dencalac # 21ZA, manufactured by Denki Kagaku Kogyo KK, Tg = 62 ° C., polymerization degree 240) was used as the adhesive in Reference Example 3. In the same manner as in Reference Example 3, a thermal transfer cover film used in the present invention was obtained.

Reference Example 5 The procedure of Reference Example 3 was repeated except that a vinyl chloride / vinyl acetate copolymer (VYHH, manufactured by UCC, Tg = 72 ° C., polymerization degree 450) was used as the adhesive in Reference Example 3. A thermal transfer cover film used in the invention was obtained.

Examples 1 to 3 100 parts of polyvinyl chloride (degree of polymerization 800) compound containing about 10% by weight of additives such as stabilizers, 10 parts of white pigment (titanium oxide) and 0.5 part of plasticizer (DOP) The sublimation dye layer of the sublimation type thermal transfer film of Reference Example 1 is superimposed on the surface of the card base comprising A face photograph image is formed, and then characters and symbols are transferred and formed using the heat transfer film of the fusion transfer type of Reference Example 2. Further, a transparent resin is applied to each image portion using the heat transfer cover films of Reference Examples 3 to 5 described above. The layers were transferred by the same thermal head to obtain a card having a face photograph and various necessary information.

Comparative Example 1 An acrylic resin (BR-
102, manufactured by Mitsubishi Rayon Co., Ltd., Tg = 20 ° C., polymerization degree 5,0
A cover film was prepared in the same manner as in Reference Example 3 except that Example No. 00) was used, and a card was prepared in the same manner as in Example 1.

Comparative Example 2 A cover was prepared in the same manner as in Reference Example 3 except that a vinyl chloride / vinyl acetate copolymer (VAGH, manufactured by UCC, Tg = 79 ° C., degree of polymerization: 450) was used as the adhesive in Reference Example 3. A film was prepared, and a card was prepared in the same manner as in Example 1.

Comparative Example 3 A cover was prepared in the same manner as in Reference Example 3 except that a vinyl chloride / vinyl acetate copolymer (VYNS, manufactured by UCC, Tg = 79 ° C., degree of polymerization 700) was used as the adhesive in Reference Example 3. A film was prepared, and a card was prepared in the same manner as in Example 1.

Evaluation Example The cards obtained above were evaluated and the results shown in Table 1 below were obtained.

[Table 1]

[0038]

According to the present invention as described above, the heat-sensitive adhesive layer provided on the surface of the transparent resin layer is made of a resin having a specific polymerization degree.
In addition, by forming the transparent resin layer from a resin having a Tg of 40 to 75 ° C., the transparent resin layer can be well transferred by a thermal head with good foil cutting. Therefore, since the transparent resin layer is easily transferred onto the image by the heat of the thermal head, an image having excellent durability, especially excellent friction resistance, chemical resistance, solvent resistance, etc. can be obtained by a simple operation.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating a cross section of a thermal transfer cover film used in the present invention.

FIG. 2 is a diagram schematically illustrating a cross section of a card created using the cover film.

[Explanation of symbols]

 1: base film 2: transparent resin layer 3: release layer 4: back layer 5: adhesive layer 6: card base 7: color image 8: letters, etc.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-23096 (JP, A) JP-A-4-35988 (JP, A) JP-A-3-159794 (JP, A) JP-A-3-230 142288 (JP, A) International Publication 90/2660 (WO, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41M 5/38-5/40 B41M 7/00

Claims (3)

(57) [Claims] 1. A transparent resin layer is provided on a base film so as to be peelable, and a surface having an average degree of polymerization of 50 to 300 is further provided on the surface thereof.
Polyvinyl chloride, polyvinyl acetate and vinyl chloride / vinyl acetate
Glass transition temperature 4 selected from the group consisting of benzyl copolymers
A heat-transfer cover film provided with a heat-sensitive adhesive layer made of a resin at 0 to 75 ° C. is superposed on the surface of the transfer-receiving member with the adhesive layer facing the surface, and heated from the base film side of the heat-transfer cover film. A method for forming a protective layer, comprising: transferring and bonding the transparent resin layer of a heated portion to a transfer object; and peeling the transparent resin layer other than the heated portion together with the base film from the transfer object. 2. The method according to claim 1, wherein a release layer is provided between the base film and the transparent resin layer. 3. The method according to claim 1, wherein the transparent resin layer contains a filler, a lubricant, an ultraviolet absorber, an antioxidant, and / or a fluorescent whitening agent.