JP3088780B2 - Thermal transfer image receiving sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer image-receiving sheet, and more particularly, to a thermal transfer image-receiving sheet which is excellent in adhesiveness of a dye receiving layer and cushioning property at the time of printing, and can form a high-density and high-resolution image. Aim.

[0002]

2. Description of the Related Art Various thermal transfer methods have been conventionally known. Among them, a sublimable dye is used as a recording agent, and this is carried on a base sheet such as paper or a plastic sheet to form a thermal transfer sheet. There have been proposed methods for forming various full-color images on a thermal transfer image-receiving sheet that can be dyed with a dye, for example, a thermal transfer image-receiving sheet provided with a dye-receiving layer on the surface of paper or a plastic film.

In this case, a thermal head of a printer is used as a heating means, and a large number of color dots of three or four colors are transferred to a thermal transfer image receiving sheet by heating for a very short time, and the multicolored dots are used to copy an original. Is reproduced. The image formed in this way is
It is very clear because the coloring material used is a dye,
And, because of its excellent transparency, the resulting image is excellent in the reproducibility and gradation of intermediate colors, similar to images by conventional offset printing or gravure printing, and has high quality images comparable to full-color photographic images. It can be formed.

[0004]

The thermal transfer image-receiving sheet used in the sublimation type thermal transfer system as described above includes:
Pulp paper, plastic sheet, laminated sheet of plastic sheet and paper, synthetic paper, etc. are used as the base sheet, and the surface is made of thermoplastic resin such as polyester resin, vinyl chloride resin, vinyl chloride / vinyl acetate copolymer resin. Although a dye receiving layer having a dye receiving layer is used, these image receiving sheets have a problem that the dye receiving layer is easily peeled off by heat from a thermal head at the time of thermal transfer or is easily peeled off with an adhesive tape or the like. In order to form a clear image, sufficient whiteness is required. However, when a large amount of a white pigment is contained in the dye-receiving layer, there is a problem that the dyeability of the dye is reduced. Further, in order to eliminate lack of printing and white spots and to obtain a high-resolution image, the image receiving sheet is required to have sufficient cushioning properties in order to improve the contact between the thermal head and the dye receiving layer. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art and to provide a thermal transfer image-receiving sheet excellent in adhesiveness, whiteness, cushioning properties and the like.

[0005]

The above object is achieved by the present invention described below. That is, the present invention comprises a substrate sheet and a dye-receiving layer formed on the surface of the substrate via an intermediate layer, wherein the intermediate layer comprises an unmodified chlorinated polypropylene resin .
A thermal transfer image-receiving sheet, characterized in that the thermal transfer image-receiving sheet is formed to a thickness of 1 to 3 μm .

[0006]

[Action] The intermediate layer of the non-modified chlorinated polypropylene resin
The thermal transfer image-receiving sheet having excellent adhesiveness and cushioning property can be provided by forming the sheet to a specific thickness . Also, by adding a white pigment, a filler, a fluorescent brightener, etc. to the intermediate layer, the base color of the base material is concealed without impairing the dye-dyeing properties of the dye-receiving layer, and the dye-receiving layer having a high whiteness is used. Is formed.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to preferred embodiments. As the base sheet used in the present invention, synthetic paper (polyolefin, polystyrene, etc.), woodfree paper, art paper, coated paper, cast-coated paper, wallpaper, backing paper, synthetic resin or emulsion impregnated paper, synthetic rubber latex Various plastic films or sheets such as impregnated paper, paper with synthetic resin, paperboard, cellulose fiber paper, polyolefin, polyvinyl chloride, polyethylene terephthalate, polystyrene, polymethacrylate, and polycarbonate can be used. A white opaque film formed by adding a white pigment or a filler to a resin, a foamed foamed sheet, or the like can be used, and is not particularly limited. The thickness of these base sheets is about 10
It is preferably about 500 μm.

[0008] unmodified chlorinated polypropylene resin for forming an intermediate layer over the surface of the substrate sheet, may be either a low-chlorinated or high chlorinated, but in particular chlorine content of 20 to 40 wt% Low chlorinated polypropylene is preferred . The intermediate layer in the present invention is a non-modified chlorinated polypropylene, acrylic resins, urethane resins, polyester resins, vinyl chloride resins, vinyl acetate resins, ethylene /
It may be a mixture with another resin such as a vinyl acetate copolymer. In that case, it is desirable that the chlorinated polypropylene is present in an amount of 10% by weight or more of the whole. The formation of the intermediate layer includes various methods such as a gravure coating method, a screen printing method, and a cast coating method, but is not limited to these methods.

In a preferred embodiment of the present invention, the above-mentioned intermediate layer contains a white pigment, a filler and / or an optical brightener. The method for incorporating these white pigments and the like may be such that the coating liquid used at the time of forming the intermediate layer contains the white pigments and the like. The white pigment or the filler has the purpose of improving the whiteness and the hiding power of the intermediate layer and preventing the ground color of the base sheet from adversely affecting the image. Examples of such white pigments or fillers include white pigments such as titanium oxide, zinc oxide, kaolin clay, calcium carbonate, and finely divided silica. The amount of the white pigment or the like to be added varies depending on the type of the pigment or the like to be used, but is generally about 1 to 500 parts by weight per 100 parts by weight of the resin for forming the intermediate layer.

[0010] The fluorescent whitening agent improves the whiteness by eliminating the yellowishness of the resin in the intermediate layer. A known fluorescent whitening agent such as an organic, naphthalimide or thiophene type is used. These fluorescent whitening agents are dissolved in the resin for the intermediate layer, and exhibit a sufficient effect at an extremely low concentration, for example, a concentration of 0.01 to 5% by weight.

The dye receiving layer formed on the surface of the base sheet is for receiving the sublimable dye transferred from the thermal transfer sheet and maintaining the formed image. As a binder resin for forming a dye receiving layer, for example,
Polyolefin resins such as polypropylene, vinyl halide resins such as polyvinyl chloride and polyvinylidene chloride, vinyl resins such as polyvinyl acetate and polyacrylester, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, and polystyrene resins , Polyamide resins, copolymer resins of olefins such as ethylene and propylene and other vinyl monomers, ionomers, cellulose resins such as cellulose diacetate, polycarbonates, and the like. Particularly preferred are vinyl resins and polyesters. It is a system resin.

The dye-receiving layer in the thermal transfer image-receiving sheet of the present invention is provided on at least one surface of the above-mentioned base sheet by adding the above-mentioned binder resin to a binder resin such as a releasing agent, an antioxidant, and an ultraviolet absorber. Dispersed in a suitable organic solvent or dispersed in an organic solvent or water, for example, a gravure printing method, a screen printing method, a reverse roll coating method using a gravure plate, etc. It is formed by coating and drying by a forming means.

The dye-receiving layer preferably contains a release agent in order to provide good releasability from the thermal transfer sheet. Preferred release agents include silicone oil, phosphate ester-based surfactants, fluorine-based surfactants, and the like, with silicone oil being preferred. As the silicone oil, epoxy-modified, alkyl-modified, amino-modified, carboxyl-modified, alcohol-modified, fluorine-modified,
Modified silicone oils such as alkyl aralkyl polyether-modified, epoxy / polyether-modified, and polyether-modified are preferred. One or more release agents are used. The amount of the release agent is preferably 1 to 20 parts by weight based on 100 parts by weight of the binder resin. If the addition amount is not satisfied, problems such as fusion of the thermal transfer sheet and the dye receiving layer or reduction in printing sensitivity may occur. The dye-receiving layer formed as described above may have any thickness, but generally has a thickness of 1 to 50 μm. Further, such a dye receiving layer is preferably a continuous coating, but may be formed as a discontinuous coating using a resin emulsion or a resin dispersion.

In the present invention, the dye receiving layer is preferably formed by a transfer method. That is, when a pulp paper substrate is used as the sheet, the surface smoothness may be insufficient, and in this case, irregularities or pinholes may occur in the dye receiving layer formed by the coating method. However, such a problem does not occur according to the transfer method. The transfer method includes, for example, forming the above-described dye-receiving layer on a film surface having good releasability such as a polyester film, and further forming an adhesive layer made of a resin having a glass transition temperature of −80 to 20 ° C. In this method, the pressure-sensitive adhesive layer is formed, bonded to the pulp paper base material surface with a laminator or the like, and then the polyester film is peeled off.

Further, for the purpose of improving the transportability of the image receiving sheet in the printer, a resin having excellent lubricity such as acrylic resin or acrylic silicone resin or an appropriate lubricating material is provided on the opposite surface of the dye receiving layer. It is also preferable to form a slip layer having a thickness of, for example, about 1 to 5 g / m ² by adding the conductive particles. The thermal transfer sheet used when performing thermal transfer using the thermal transfer image receiving sheet of the present invention as described above,
A dye layer containing a sublimable dye is provided on paper or polyester film, and any conventionally known thermal transfer sheets can be used in the present invention as they are. As a means for applying thermal energy at the time of thermal transfer, any conventionally known applying means can be used. For example, the recording time is controlled by a recording device such as a thermal printer (for example, a video printer VY-100 manufactured by Hitachi, Ltd.). By doing so, the intended purpose can be sufficiently achieved by applying thermal energy of about 5 to 100 mJ / mm ² .

[0016]

Next, the present invention will be described more specifically with reference to examples and comparative examples. In the following description, parts and% are based on weight unless otherwise specified. Example 1 Synthetic paper having a thickness of 200 μm (trade name: Yupo, manufactured by Oji Yuka)
Is coated with a coating solution for an intermediate layer having the following composition by a bar coater at a rate of 1.0 g / m ² when dried, dried with a drier, and dried in an oven at 100 ° C. for 5 minutes to form an intermediate layer. The following coating liquid for a receiving layer is applied on the intermediate layer by a bar coater at a rate of 3.0 g / m ² when dried, and dried in an oven at 100 ° C. for 5 minutes to obtain the thermal transfer image-receiving image of the present invention. I got a sheet. Coating liquid composition for intermediate layer ; Chlorinated polypropylene (Hardlen 13B, manufactured by Toyo Kasei) 50 parts Ethylene / vinyl acetate copolymer (Evaflex 40)
Y, made by Mitsui Dupont Chemical)
50 parts Optical brightener (Ubitex OB, Ciba-Geigy)
0.1 parts toluene
100 parts coating liquid composition for receiving layer ; polyester resin (Byron 103, manufactured by Toyobo)
100 parts Amino-modified silicone (X-22-343, manufactured by Shin-Etsu Chemical) 3 parts Epoxy-modified silicone (KF-393, manufactured by Shin-Etsu Chemical) 3 parts Methyl ethyl ketone / toluene (weight ratio (1/1))
500 copies

Example 2 The following coating liquid for an intermediate layer was applied to a foamed polypropylene sheet (Toyopearl SS # 35, manufactured by Toyobo, 35 μm in thickness) at a solid content of 2 g / m ² and dried. Was coated with a coating solution for a receiving layer having the following composition at a rate of 2.0 g / m ² when dried with a bar coater, temporarily dried with a drier, and then dried in an oven at 100 ° C. for 30 minutes to obtain a dye receiving layer. Was formed to obtain a thermal transfer image-receiving sheet of the present invention. Coating composition for intermediate layer ; Chlorinated polypropylene (Hard Len 15LPB, manufactured by Toyo Kasei) 100 parts Titanium oxide (TCR-10, manufactured by Tochem Products)
100 parts toluene
100 parts Coating composition for receptor layer ; Vinyl chloride / vinyl acetate copolymer resin (VYHD, manufactured by Union Carbide) 100 parts Epoxy-modified silicone (KF-393, manufactured by Shin-Etsu Chemical Co., Ltd.) 3 parts Amino-modified silicone (KP343, Shin-Etsu Chemical industry)
3 parts methyl ethyl ketone / toluene (weight ratio (1/1))
400 copies

Example 3 A 100 μm-thick polyester film (trade name “Lumirror”, manufactured by Toray Co., Ltd.) was coated with a coating solution for an intermediate layer having the following composition by a bar coater to 3.0 g / m ² when dried. And dried with a drier to form an intermediate layer. Further, the following coating liquid for a receiving layer was dried on the intermediate layer at a rate of 4.0 g /
The composition was applied and dried with a bar coater at a ratio of m ² to obtain a thermal transfer receiving sheet of the present invention. Coating liquid composition for intermediate layer ; chlorinated polypropylene (Hardlen 15LPB, manufactured by Toyo Kasei) 50 parts Titanium oxide (TCA888, manufactured by Tochem Products)
100 parts toluene
100 parts Coating composition for receptor layer ; Vinyl chloride / vinyl acetate copolymer resin (VYHD, manufactured by Union Carbide) 100 parts Amino-modified silicone (X-22-343, manufactured by Shin-Etsu Chemical Co., Ltd.) 2 parts Epoxy-modified silicone (KF -393, manufactured by Shin-Etsu Chemical Co., Ltd.) 2 parts Methyl ethyl ketone / toluene (weight ratio (1/1))
100 copies

Comparative Example 1 A thermal transfer image-receiving sheet of Comparative Example was obtained in the same manner as in Example 1 except that the following thermoplastic resin solution was used as the coating liquid for the intermediate layer. Intermediate layer coating liquid composition: Acrylic resin (DIANAL BR85, manufactured by Mitsubishi Rayon) 20 parts Toluene
100 parts Comparative Example 2 A thermal transfer image-receiving sheet of a comparative example was obtained in the same manner as in Example 1 except that the intermediate layer was not formed.

On the other hand, an ink for a dye layer having the following composition was prepared and applied to a 6 μm-thick polyethylene terephthalate film whose back surface was heat-treated at a dry coating amount of 1.0 g / m ^2.
After coating and drying with a wire bar, a few drops of silicone oil (X-41.403A, manufactured by Shin-Etsu Silicone) are dropped on the back with a dropper, then spread over the entire surface and coated on the back to obtain a thermal transfer film. Was. Ink composition for dye layer : Disperse dye (Kayaset Blue 714, manufactured by Nippon Kayaku)
4.0 parts ethyl hydroxycellulose (manufactured by Hercules)
5.0 parts methyl ethyl ketone / toluene (weight ratio 1/1)
80.0 parts dioxane
10.0 parts The above-mentioned thermal transfer film is superimposed on the surface of the receiving layer of each of the image receiving sheets, and the output is 1 W / dot by using a thermal head.
Pulse width 0.3 to 0.45 msec. When printing was performed under the condition of a dot density of 3 dots / mm to form a cyan image, when the thermal transfer image-receiving sheet of the example was used,
There was no problem of peeling of the dye receiving layer, and it was a high quality image without defective parts such as color omission, but when the thermal transfer image receiving sheet of the comparative example was used, the dye receiving layer was partially peeled. An image of poor quality was observed with defective portions such as color loss and color omission.

[0021]

According to the present invention as described above, by forming the intermediate layer to a specific thickness containing an unmodified chlorinated polypropylene resin , it is possible to provide a thermal transfer image-receiving sheet having excellent cushioning properties. I can do it. Further, by adding a white pigment, a filler, a fluorescent whitening agent and the like to the intermediate layer, the background color of the base material is concealed and a dye receiving layer having high whiteness is formed.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B41M 5/38-5/40

Claims (3)

(57) [Claims] 1. A consists substrate sheet and the dye-receiving layer formed over the intermediate layer on the surface thereof, said intermediate layer is unmodified
1 to 3 µm thickness including chlorinated polypropylene resin
A thermal transfer image-receiving sheet characterized by being formed . 2. The thermal transfer image-receiving sheet according to claim 1, wherein the intermediate layer contains a white pigment, a filler and / or a fluorescent whitening agent. 3. The thermal transfer image-receiving sheet according to claim 1, wherein the base sheet is made of pulp paper, synthetic paper, or synthetic resin film.