JP2003025736A - Thermal transfer sheet and printed matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal transfer sheet which has excellent forgery/ falsification preventiveness and which imparts a printed matter having excellent design properties. SOLUTION: The thermal transfer sheet comprises a mold release layer, an intermediate layer and a heat sensitive adhesive layer sequentially laminated on one surface of a base film. In this sheet, the intermediate layer and the adhesive layer each contains a fluorescent agent which emits a fluorescence when the agent is irradiated with an ultraviolet ray.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer sheet incorporating a fluorescent agent for the purpose of improving anti-counterfeiting / tampering property, designability and amusement property. More specifically, the printed matter exhibits a higher emission intensity. The present invention relates to a thermal transfer sheet which exhibits a more complicated luminescent color and gives a printed matter which is difficult to forge and falsify.

[0002]

2. Description of the Related Art Conventionally, in order to prevent counterfeiting or falsification of printed matter such as documents, cash vouchers, cards, etc., it cannot be recognized by ordinary visible light, but when it is irradiated with ultraviolet rays, it emits fluorescence and can be identified. A means for providing a fluorescent latent image on the surface of the printed matter is known.

In addition, as a conventional simple printing means,
Thermal transfer methods are widely used. In the conventional technique, as disclosed in Japanese Patent Application Laid-Open No. 7-68946, a transparent fluorescent agent or a semi-transparent fluorescent agent is contained in the intermediate layer to have a forgery / tampering prevention effect.

However, in such a case, since only one thin fluorescent layer having a thickness of several μm is usually formed, the fluorescent brightness of the emitted light is not so high, and the fluorescent color is often monochromatic. . It is clear that when the fluorescent color is a single color, the manufacturing method of the thermal transfer sheet is simpler than that of the mixed color, and the forgery / tampering prevention effect is deteriorated.

[0005]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art and to provide a thermal transfer sheet which is excellent in anti-counterfeiting / tampering property and gives a printed matter having excellent designability. Is.

[0006]

The above object can be achieved by the present invention described below. That is, the present invention is a thermal transfer sheet in which a release layer, an intermediate layer and a heat-sensitive adhesive layer are sequentially laminated on one surface of a base film, and the intermediate layer and the heat-sensitive adhesive layer emit fluorescence when irradiated with ultraviolet rays. Provided is a thermal transfer sheet containing a fluorescent agent.

According to the present invention described above, a fluorescent agent is added to both the intermediate layer and the heat-sensitive adhesive layer of the thermal transfer sheet to enhance the fluorescent brightness, and further, fluorescent agents of different fluorescent colors are added to the respective layers. Thus, a printed matter that emits a more complicated fluorescent color and has improved anti-counterfeiting / falsification effect and designability is provided.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the following preferred embodiments. FIG. 1 is a diagram schematically showing a basic form of a cross section of a thermal transfer sheet of the present invention. As shown in FIG. 1, the thermal transfer sheet of the present invention comprises a release layer 2, an intermediate layer 3 and a heat-sensitive adhesive layer 4 which are sequentially laminated on one surface of a base film 1 to form the intermediate layer 3 and the heat-sensitive adhesive layer 4. Both of them are characterized by containing a fluorescent agent that emits fluorescence when irradiated with ultraviolet rays.

(Base Film) The base film used in the present invention may be any one as long as it has a conventionally known degree of heat resistance and strength. For example,
Preferably 0.5 to 50 μm, more preferably 3 to 10
Paper with thickness of about μm, various processed papers, polyester film, polystyrene film, polypropylene film,
Examples thereof include polysulfone film, polycarbonate film, aramid film, polyvinyl alcohol film, cellophane, and the like, and polyester film is particularly preferable. A heat resistant slipping layer (not shown) for preventing fusion of the thermal head can be provided on the back surface of these base films.

(Release Layer) A release layer is provided on the base film to facilitate separation of the intermediate layer and the heat-sensitive adhesive layer from the base film. As the resin used for the release layer,
Examples thereof include acrylic resins, urethane resins, resins obtained by modifying each of these resins with silicone, polyvinyl acetal resins, polyvinyl alcohol resins, and mixtures thereof. These resins are dissolved in a solvent to prepare a coating liquid, and the coating liquid is applied and dried to form a release layer. The thickness of the release layer is about 0.1 to 5.0 μm.

(Intermediate layer) This layer is the uppermost layer after transfer and is made of a resin having various durability. Examples of the resin used for the intermediate layer include polyester resin, polystyrene resin, acrylic resin, polyurethane resin, acrylic urethane resin, vinyl chloride resin, vinyl acetate resin, vinyl chloride / vinyl acetate copolymer resin, polyamide resin, Examples of the resin include resins obtained by modifying each of these resins with silicone, and mixtures of these resins. These resins and fluorescent agents are dissolved or dispersed in a solvent to prepare a coating liquid, and the coating liquid is applied and dried to form an intermediate layer. The thickness of the intermediate layer is about 0.2 to 5.0 μm.
These intermediate layers are preferably colorless and transparent so that the image coated with the intermediate layers can be visually observed.

(Heat-Sensitive Adhesive Layer) A layer for transferring and adhering the intermediate layer to the image surface formed on the image-receiving sheet, which is a so-called heat-sealing resin. Specific examples thereof include resins having good adhesiveness when heated, such as acrylic resin, vinyl chloride resin, vinyl acetate resin, vinyl chloride / vinyl acetate copolymer resin, polyester resin, and polyamide resin. . The resin and the fluorescent agent are dissolved or dispersed in a solvent to prepare a coating liquid, and the coating liquid is applied and dried to form a heat-sensitive adhesive layer. The thickness of the heat-sensitive adhesive layer is about 0.1 to 5 μm. These heat-sensitive adhesive layers are preferably colorless and transparent so that the image coated with the heat-sensitive adhesive layers can be visually observed.

The total thickness of the above intermediate layer and heat-sensitive adhesive layer is in the range of 0.3 to 10 μm, preferably 0.4 to 5 μm. If the thickness is less than 0.3 μm, the layer thickness becomes poor in uniformity, which causes unevenness in the fluorescent color. On the other hand, when the thickness is more than 10 μm, the foil cutting property of the intermediate layer and the heat-sensitive adhesive layer (hereinafter sometimes referred to as “fluorescent agent-containing layer”) at the time of transfer is lowered, and the intermediate layer and the heat-sensitive adhesive layer are formed only in a desired region. Is difficult to transfer, and transfer occurs in areas other than the desired area.

(Fluorescent agent) As the fluorescent agent used in the present invention, many organic and inorganic fluorescent agents are known.
In the present invention, any known fluorescent agent can be used, but in order to prevent the image covered by the fluorescent agent-containing layer from being hidden, it is dissolved in the resin of the heat-sensitive adhesive layer and the intermediate layer, and is normally colorless organic. Fluorescent agents are preferred. Examples of the organic fluorescent agent include EB-501 and EG-50 manufactured by Mitsui Chemicals, Inc.
2, ER-120 (trade name), Nippon Kayaku Co., Ltd. EuN-0001 (trade name), Ciba-Geigy Ubitex OB (trade name), Shin Lohi Co., Ltd. colorless fluorescence Coloring materials, various fluorescent whitening agents and the like can be used.

The amount to be added to the intermediate layer and the heat-sensitive adhesive layer may be arbitrarily determined according to performance requirements and is not particularly limited, but the phase of the fluorescent agent and the resin for the intermediate layer and the adhesive layer may be selected. When the solubility is not high, if the compounding ratio of the fluorescent agent is increased too much, the fluorescent agent may be precipitated in the layer.
Therefore, the mixing ratio of the fluorescent agent is preferably about 0.01 to 50% by weight, and more preferably about 0.1 to 20% by weight based on the total weight of the intermediate layer and the heat-sensitive adhesive layer.

(Image-Receiving Sheet) The image-receiving sheet used for forming an image using the thermal transfer sheet of the present invention as described above may be paper, plastic sheet, cloth, or any other image-receiving sheet. In the case of using a thermal transfer sheet having a sublimation dye layer which will be described later in a frame-sequential manner, it is necessary that the image forming surface of the image receiving sheet is dye-dyeable. For example, in the case of a paper substrate having no dye-dyeing property, a dye-receiving layer is provided by using a polyester resin having a good dye-dyeing property.

(Transfer Method) The transfer method using the thermal transfer sheet of the present invention is a conventional transfer method such as hot press, thermal roll, thermal printer, etc. with the surface of the thermal transfer adhesive sheet of the present invention facing the image receiving sheet. Can be used. When transferring the fluorescent agent-containing layer in a pattern,
A method of forming the fluorescent agent-containing layer in a pattern in advance,
A recording device such as a thermal printer, for example, a thermal printer (for example, a video printer VY-100 manufactured by Hitachi) controls the recording time to give a thermal energy of about 5 to 100 mJ / mm ² in a pattern. Can be transferred to.

At the time of such transfer, an image may be formed in advance in the transfer area, or an image may not be formed. The example shown in FIG. 2 shows an example in which a monocolor or full-color image 6 is previously formed on the image receiving sheet 5 by the sublimation transfer method, and the fluorescent agent-containing layer is transferred and formed so as to cover the image 6. In the image thus formed, when the fluorescent agent contained in the fluorescent agent-containing layer is irradiated with ultraviolet rays, the fluorescent agent emits light, and the hue of the image 6 remarkably changes. It will be difficult.

(Other Embodiments) In the present invention, the heat-sensitive adhesive layer and the intermediate layer contain a fluorescent agent, but the fluorescent agents added to each may be the same or different, or may be a mixture. When the same fluorescent agent is contained in both the heat-sensitive adhesive layer and the intermediate layer, strong fluorescence emission can be obtained by ultraviolet irradiation. On the other hand, in the case where both the heat-sensitive adhesive layer and the intermediate layer contain fluorescent agents having different fluorescent colors, the color mixture of both fluorescent agents can be obtained by irradiation with ultraviolet rays. In this case, it is more difficult to forge or falsify the print.

In another embodiment of the present invention, as shown diagrammatically in FIG. 3, at least one of yellow, magenta, cyan, and black colors is provided on the same side of the same base film in a frame order with the fluorescent agent-containing layer. It is possible to form one or more layers selected from sublimable dye layers of one or more colors and heat-meltable black ink layers. In the case of the heat-fusible ink layer, the release layer as described above can be provided between the base film and the ink layer.

In FIG. 3, the color material layers of yellow (Y), magenta (M), cyan (C) and black (Bk) are:
It may be a sublimable dye layer composed of all sublimable dyes and a binder, or all the color material layers may be heat-meltable ink layers composed of an appropriate color material and wax or a thermoplastic resin. In a preferred embodiment, yellow, magenta and cyan are sublimable dyes, a full-color gradation image is formed by these three colors, a black layer is a heat-melting type ink layer, and the black layer prevents non-printing of characters and the like. It forms a gradation image. Sublimation dyes used in such embodiments, binders thereof, heat-melting materials such as waxes, coloring materials thereof, and materials such as dye layers and ink layers and forming methods are known, and each layer is formed according to the known methods. Can be formed.

Further, in the present invention, as shown in FIG. 3, a transferable protective layer 7 can be provided on the same surface of the base film 1 in a plane-sequential manner with the fluorescent agent-containing layer. As the protective layer forming material and forming method, various kinds of resins conventionally known as protective layer forming resins can be used. As the protective layer forming resin, for example, polyester resin, polystyrene resin, acrylic resin, polyurethane resin, acrylic urethane resin, a resin obtained by silicone modification of each of these resins, a mixture of these resins, ionizing radiation curable resin It can be illustrated.

The above resin is dissolved in a solvent to prepare a coating liquid, and the coating liquid is applied and dried to form a transferable protective layer. The thickness of the protective layer is about 0.5 μm to 10 μm. FIG. 4 schematically shows a state in which the fluorescent agent-containing layers 3 and 4 are transferred onto the surface of the sublimable dye image 6, and further the protective layer 7 is transferred onto the surface thereof. By transferring the protective layer 7 in this way, various durability such as weather resistance, chemical resistance, and scratch resistance of the image 6 and the fluorescent agent-containing layers 3 and 4 can be improved.

[0024]

EXAMPLES Next, the present invention will be described more specifically with reference to Examples and Comparative Examples. In addition, "part" or "%" in the sentence
Unless otherwise specified, the weight is based on the weight.

<Preparation of Base Film 1> The surface of a polyester film having a thickness of 6 μm was coated and dried with a gravure coater to a coating amount of 0.5 μm on a surface of a polyester film, and a base film was obtained. It was set to 1.

[0026] <Coating liquid for heat resistant slipping layer>   Polyvinyl butyral resin (S-REC BX-1, Sekisui Chemical Co., Ltd.) 3.6 parts   Polyisocyanate (Bernock D750, manufactured by Dainippon Ink and Chemicals) 8.6 parts   Phosphate ester type surfactant (Prysurf A208S, manufactured by Daiichi Pharmaceutical Co., Ltd.)                                                                 2.8 copies   Talc (Microace P-3, manufactured by Nippon Talc Industry Co., Ltd.) 0.7 parts   Methyl ethyl ketone 32.0 parts   Toluene 32.0 parts

Example 1 On the surface of the base film 1 opposite to the heat resistant slipping layer side, a release layer coating solution having the following composition was applied in an amount of 0.5 μm and an intermediate layer coating solution was applied in an amount of 1 0.0 μm, using a gravure coater so that the coating amount for the heat-sensitive adhesive layer is 1.0 μm,
The thermal transfer sheet of the present invention was obtained by sequentially coating, drying and laminating.

[0028] <Release layer coating liquid>   16 parts of silicone modified acrylic resin (Celltop 226, Daicel Chemical Co., Ltd.)   Aluminum catalyst (Celltop CAT-A, manufactured by Daicel Chemical Industries) 3 parts   Methyl ethyl ketone 8 parts   Toluene 8 parts

[0029] <Coating liquid for intermediate layer>   Acrylic resin (Thermolac LP45M, Soken Chemical Co., Ltd.) 100 parts   Colorless fluorescent agent (blue light emission, manufactured by Ciba Geigy) 1 part   Methyl ethyl ketone 50 parts   Toluene 50 parts

[0030] <Coating liquid for heat-sensitive adhesive layer>   Vinyl chloride-vinyl acetate copolymer resin (1000A, manufactured by Denki Kagaku Kogyo) 100 parts   Colorless fluorescent agent (blue light emission, manufactured by Ciba Geigy) 1 part   150 parts of toluene   Methyl ethyl ketone 150 parts

Example 2 A thermal transfer sheet of the present invention was obtained in the same manner as in Example 1 except that the composition of the coating liquid for heat-sensitive adhesive layer was changed to the following in the constitution of Example 1.

[0032] <Coating liquid for heat-sensitive adhesive layer>   Vinyl chloride-vinyl acetate copolymer resin (1000A, manufactured by Denki Kagaku Kogyo) 100 parts   Colorless fluorescent agent (green color, made by Shin Loihi) 1 part   150 parts of toluene   Methyl ethyl ketone 150 parts

<Preparation of Base Film 2> Next, on the side opposite to the heat resistant slipping layer side of the base film 1, the following coating liquid for yellow ink layer, coating liquid for magenta ink layer, and cyan ink layer were prepared. The coating liquid and the coating liquid for the black ink layer were applied face-sequentially so as to have a coating amount of 1.0 μm and dried to obtain a base film 2.

[0034] <Coating liquid for yellow ink layer>   Yellow dye (Macrolex Yellow 6G, Bayer, C.I.Dlsperse    Yellow 201) 5.5 copies   Polyvinyl acetoacetal (S-REC KS-5, Sekisui Chemical) 4.5 parts   Methyl ethyl ketone / toluene (weight ratio 1/1) 89.0 parts

[0035] <Coating liquid for magenta ink layer>   Magenta dye (C.I.Dlsperse Red 60) 5.5 parts   Polyvinyl acetoacetal (S-REC KS-5, Sekisui Chemical) 4.5 parts   Methyl ethyl ketone / toluene (weight ratio 1/1) 89.0 parts

[0036] <Coating liquid for cyan ink layer>   Cyan dye (C.I.Solvent Blue 63) 5.5 parts   Polyvinyl acetoacetal (S-REC KS-5, Sekisui Chemical) 4.5 parts   Methyl ethyl ketone / toluene (weight ratio 1/1) 89.0 parts

[0037] <Coating liquid for black ink layer>   Carbon black 9 parts   Vinyl chloride-vinyl acetate copolymer resin (1000A, manufactured by Denki Kagaku Kogyo) 18 parts   Methyl ethyl ketone / toluene (weight ratio 1/1) 73 parts

Example 3 In the configuration of Example 1, the base film 1 was changed to the base film 2, and a release layer, an intermediate layer and a heat-sensitive adhesive layer were sequentially coated and dried to be laminated after the black ink layer. To obtain a thermal transfer sheet of the present invention.

Example 4 In the configuration of Example 2, the base film 1 was changed to the base film 2, and after the black ink layer, the release layer, the intermediate layer and the heat-sensitive adhesive layer were sequentially coated and dried to be laminated. A thermal transfer sheet of the present invention was obtained.

Example 5 In the constitution of Example 4, after the fluorescent agent-containing layer, a release layer coating solution having the following composition was applied at a coating amount of 0.5 μm, and a protective layer coating solution was coated at a coating amount of 1.0 μm. After processing and drying, a thermal transfer sheet of the present invention was obtained.

[0041] <Release layer coating liquid>   16 parts of silicone modified acrylic resin (Celltop 226, Daicel Chemical Co., Ltd.)   Aluminum catalyst (Celltop CAT-A, manufactured by Daicel Chemical Industries) 3 parts   Methyl ethyl ketone 8 parts   Toluene 8 parts

[0042] <Coating liquid for protective layer>   Acrylic resin (BR-85, manufactured by Mitsui Chemicals) 50 parts   Vinyl chloride-vinyl acetate copolymer resin (1000A, manufactured by Denki Kagaku Kogyo) 50 parts   25 parts of methyl ethyl ketone   25 parts of toluene

Example 6 In the construction of Example 4, a fluorescent agent-containing layer was applied after the black ink layer to the center of the film in a size of 1/8 of the coating area of the black ink layer, and the thermal transfer of the present invention was performed. Got the sheet.

Comparative Example 1 A transfer sheet of Comparative Example 1 was obtained in the same manner as in Example 1 except that the composition of the coating liquid for heat-sensitive adhesive layer in the constitution of Example 1 was changed to the following coating liquid. . <Coating liquid for heat-sensitive adhesive layer> Vinyl chloride-vinyl acetate copolymer resin (1000A, manufactured by Denki Kagaku Kogyo) 100 parts Toluene 150 parts Methyl ethyl ketone 150 parts

Evaluation Evaluation was carried out using a P-330 printer manufactured by Olympus Industry Co., Ltd. The thermal transfer image receiving sheet included in P-330 as a set was used as the printing paper.

1) The thermal transfer image-receiving sheet of Example 1 and the thermal transfer image-receiving sheet are superposed on each other, the fluorescent agent-containing layer and the thermal transfer image-receiving sheet are adhered to each other, and then the base film is peeled off so that the thermal transfer image-receiving sheet contains a colorless fluorescent agent. An image was formed of the layers. The image composed of the obtained colorless fluorescent agent-containing layer is almost colorless and difficult to be visually recognized under visible light, and when irradiated with a commercially available black light (emission wavelength 365 nm), the image forming portion emits blue light and is clearly visible. It was

2) The thermal transfer sheet of Example 2 and the thermal transfer image receiving sheet were superposed on each other, the fluorescent agent-containing layer and the thermal transfer image receiving sheet were adhered, and then the base film was peeled off, and the thermal transfer image receiving sheet contained a colorless fluorescent agent. An image was formed of the layers. The image formed of the colorless fluorescent agent-containing layer is almost colorless and difficult to see under visible light, and when irradiated with a commercially available black light (emission wavelength 365 nm), the image forming portion emits light emission of a mixture of blue and green. Shown and clearly visible.

3) The thermal transfer sheet of Example 3 and the thermal transfer image receiving sheet were superposed on each other, the fluorescent agent-containing layer and the thermal transfer image receiving sheet were adhered, and then a natural image was printed in full color with yellow, magenta, cyan and black colors. An image composed of a colorless fluorescent agent-containing layer was formed thereon. In the obtained image-receiving sheet, only a natural image was visible under visible light, and an image composed of the colorless fluorescent agent-containing layer was almost colorless and was difficult to view. Commercially available black light (emission wavelength 365n
Upon irradiation with m), the image portion consisting of the colorless fluorescent agent-containing layer emitted blue light and was clearly visible.

4) The thermal transfer sheet of Example 4 and the thermal transfer image receiving sheet were superposed on each other, the fluorescent agent-containing layer and the thermal transfer image receiving sheet were adhered, and then a natural image was printed in full color with yellow, magenta, cyan and black colors. ,in addition,
An image consisting of the colorless fluorescent agent-containing layer was formed. In the obtained image-receiving sheet, only a natural image was visible under visible light, and an image composed of the colorless fluorescent agent-containing layer was almost colorless and was difficult to view. When it was irradiated with a commercially available black light (emission wavelength 365 nm), the image forming portion showed light emission of a mixture of blue and green, which was clearly visible.

5) The thermal transfer sheet of Example 5 and the thermal transfer image receiving sheet were superposed on each other, the fluorescent agent-containing layer and the thermal transfer image receiving sheet were adhered, and then a natural image was printed in full color with yellow, magenta, cyan and black colors. An image composed of a colorless fluorescent agent-containing layer was formed thereon, and a protective layer was further transferred thereon so as to cover the entire image. Under visible light, only the natural image was visible, and the image composed of the colorless fluorescent agent-containing layer was almost colorless and difficult to see. When it was irradiated with a commercially available black light (emission wavelength 365 nm), the image forming portion showed light emission of a mixture of blue and green, which was clearly visible. Even if the obtained printed matter was rubbed with an eraser several times, no discoloration or decoloration of the image was observed.

6) The thermal transfer sheet of Example 6 and the thermal transfer image receiving sheet were superposed on each other, the fluorescent agent-containing layer and the thermal transfer image receiving sheet were adhered, and then a natural image was printed in full color with yellow, magenta, cyan and black colors. An image composed of the colorless fluorescent agent-containing layer was formed on the center of the sheet. In the obtained image-receiving sheet, only a natural image was visible under visible light, and an image composed of the colorless fluorescent agent-containing layer was almost colorless and was difficult to view. When it was irradiated with a commercially available black light (emission wavelength 365 nm), the image forming portion in the central portion of the sheet showed light emission of a mixture of blue and green, which was clearly visible.

7) The thermal transfer sheet of Comparative Example 1 and the above thermal transfer image receiving sheet were superposed, the fluorescent agent-containing layer and the thermal transfer image receiving sheet were adhered, the base film was peeled off, and the thermal transfer image receiving sheet contained the colorless fluorescent agent. An image was formed of the layers. The image formed of the colorless fluorescent agent-containing layer was almost colorless and difficult to see under visible light, and when irradiated with a commercially available black light (emission wavelength 365 nm), the image forming portion emitted blue light. The strength was low and the visibility was poor.

[0053]

According to the present invention as described above, the following effects are exhibited in addition to the effects described above. 1) By including a fluorescent agent that develops the same color tone in the intermediate layer and the heat-sensitive adhesive layer, since the fluorescence intensity (emission intensity) depends on the amount of the fluorescent agent present, a clearer color can be expressed. 2) By including a fluorescent agent having a different color tone among RGB in the intermediate layer and the heat-sensitive adhesive layer, the fluorescence intensity is increased and the fluorescence of different hues can be emitted. For example, when B is contained in the heat-sensitive adhesive layer and G is contained in the intermediate layer to emit a fluorescent agent, a color close to cyan can be expressed in accordance with the additive color mixture of B + G.

3) Usually, the heat-sensitive adhesive layer and the intermediate layer are preferably colorless and transparent for transferring on the image. Accordingly, the fluorescent agent is preferably colorless and transparent under visible light, and the organic fluorescent agent is particularly effective. In the case of an inorganic fluorescent agent, solid fine particles of an inorganic compound are used by being dispersed in a binder. Therefore, after the layer is formed, the particles often become white due to light scattering of the fine particles, which impairs colorless transparency. Moreover, when the above-mentioned color mixture is exhibited, the light emission of the lower layer is hindered. 4) By forming the fluorescent agent-containing layer in a pattern,
Cost benefits can be obtained. That is, the fluorescent agent is usually
Since it is more expensive than other dyes, the cost increase can be suppressed by applying only the necessary portion to the base film from the beginning.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a layer structure of a thermal transfer sheet of the present invention.

FIG. 2 is a diagram illustrating an aspect of use of the thermal transfer sheet of the present invention.

FIG. 3 is a diagram schematically showing a layer structure of a thermal transfer sheet according to another embodiment of the present invention.

FIG. 4 is a diagram illustrating another mode of use of the thermal transfer sheet of the present invention.

[Explanation of symbols]

1: Base film 2: Release layer 3: Middle layer 4: Heat-sensitive adhesive layer 5: Image receiving sheet 6: Image 7: Protective layer

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2C005 HA04 HB10 JB14 KA37                 2H111 AA07 AA26 BA02 BA03 BA04                       BA09 BA12 BA47 BA48 BA49                       BA50 BA55 BA76

Claims (6)

[Claims] 1. A thermal transfer sheet comprising a base film, a release layer, an intermediate layer, and a heat-sensitive adhesive layer, which are sequentially laminated on one surface of the base film. The intermediate layer and the heat-sensitive adhesive layer emit fluorescence when exposed to ultraviolet rays. A thermal transfer sheet containing an agent. 2. The thermal transfer sheet according to claim 1, wherein the fluorescent agents contained in the intermediate layer and the heat-sensitive adhesive layer have different emission colors. 3. One or more layers selected from sublimable dye layers of at least one color among yellow, magenta, cyan and black colors and a heat-meltable black ink layer are fluorescent agent-containing layers. The thermal transfer sheet according to claim 1 or 2, which is provided on the same base film surface as the intermediate layer and the heat-sensitive adhesive layer in a frame-sequential manner. 4. The thermal transfer sheet according to claim 1, wherein a protective layer is provided on the same base film surface as the fluorescent agent-containing layer in a frame sequential manner. 5. The thermal transfer sheet according to claim 1, wherein the fluorescent agent-containing layer is formed in a pattern. 6. A print product produced by using the thermal transfer sheet according to claim 1.