JPH04353493A - Thermal transfer image receiving sheet - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

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 specifically, it is an object of the present invention to provide a thermal transfer image-receiving sheet that has excellent cushioning properties and is capable of forming images with high density and high resolution.

0002

[Prior Art] Various thermal transfer methods are conventionally known, and among them, a sublimable dye is used as a recording agent, and this is supported on a base sheet such as paper or a plastic sheet to form a thermal transfer sheet. A thermal transfer image-receiving sheet that can be dyed with dyes,
For example, methods have been proposed for forming various full-color images on thermal transfer image-receiving sheets in which a dye-receiving layer is provided on the surface of paper or plastic film.

In this case, a thermal head of a printer is used as a heating means, and a large number of three or four color dots are transferred to a thermal transfer image receiving sheet by extremely short heating, and the multicolor dots are used to form a document. It reproduces a full-color image. The image formed in this way is
Because the coloring material used is dye, it is very clear,
In addition, because it has excellent transparency, the resulting images have excellent intermediate color reproducibility and gradation, are similar to images produced by conventional offset printing or gravure printing, and are of high quality comparable to full-color photographic images. It is possible to form.

0004

[Problems to be Solved by the Invention] The thermal transfer image-receiving sheet used in the above-mentioned sublimation type thermal transfer method is as follows:
The base sheets used are plastic sheets, laminated sheets of plastic sheets and paper, synthetic paper, etc., with a dye-receiving layer on the surface, but these image-receiving sheets do not form clear images. In order to do this, sufficient whiteness is required, and also to eliminate chipping and white spots in the print,
In order to obtain high-resolution images, the image-receiving sheet is required to have sufficient cushioning properties to improve contact between the thermal head and the dye-receiving layer.

[0005] Furthermore, in order to expand the use of the sublimation thermal transfer method to general offices, it is required to use plain paper such as PPC paper as the base material sheet of the image-receiving sheet. Using general office paper like this as a base sheet,
When forming a dye-receiving layer on the surface of the paper, there is a problem that the surface of the dye-receiving layer becomes rough due to the roughness of the surface of the paper.To solve this problem, a transfer method is used. A method of transferring and forming a dye-receiving layer onto the surface of paper is known. This transcription method. A receptor layer transfer film is used in which a dye receptor layer and an adhesive layer are laminated on a base film surface with good releasability. However, since the adhesive layer of the conventional receptor layer transfer film uses a heat-sensitive thermoplastic resin, heating is required to transfer the receptor layer, making high-speed transfer difficult. Furthermore, when a coarse base sheet such as pulp paper is used as the base sheet, the adhesion during high-speed transfer is insufficient. Furthermore, the resulting image-receiving sheet did not have sufficient cushioning properties. Therefore, 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 with excellent whiteness, cushioning properties, etc. with good productivity.

[0006]

[Means for Solving the Problems] The above object is achieved by the following present invention. That is, the present invention is characterized in that it consists of a base sheet and a dye-receiving layer formed on the surface thereof via an intermediate layer, and the intermediate layer is made of a resin having a glass transition temperature of -80 to 20°C. This is a thermal transfer image-receiving sheet.

[0007]

[Function] By forming the intermediate layer from a resin having a glass transition temperature of -80 to 20°C, a thermal transfer image-receiving sheet with excellent cushioning properties can be provided. Further, by adding a white pigment, a filler, a fluorescent whitening agent, etc. to the intermediate layer, the ground color of the base material is hidden, and a dye-receiving layer with high whiteness is formed. or,
By forming the image-receiving sheet using a receptor layer transfer film with the adhesive layer (intermediate layer after transfer) made of the above-mentioned resin with a glass transition temperature of -80 to 20°C, there is no need to heat even a coarse base sheet. Or by simple heating, efficient high-speed transfer becomes possible.

[0008]

[Preferred Embodiments] Next, the present invention will be explained in more detail by citing preferred embodiments. The base sheet used in the present invention includes synthetic paper (polyolefin type, polystyrene type, etc.), high quality paper, art paper, coated paper, cast coated paper, wallpaper, backing paper, synthetic resin or emulsion impregnated paper, and synthetic rubber latex. Various types of plastic films or sheets such as impregnated paper, synthetic resin-loaded paper, paperboard, cellulose fiber paper, polyolefin, polyvinyl chloride, polyethylene terephthalate, polystyrene, polymethacrylate, polycarbonate, etc. can be used, and their compositions can also be used. A white opaque film formed by adding a white pigment or a filler to a resin, a foamed sheet formed by foaming, etc. can also be used, but are not particularly limited. Particularly useful base sheets in the present invention are pulp paper bases, including various papers such as wood-free paper, art paper,
Coated paper, cast coated paper, thermal transfer paper, Kent paper, etc. are used, and the thickness is preferably 130 μm or less in order to produce a texture similar to plain paper. If it is too thin, problems will arise in the strength, transportability, etc. within the printer, so the lower limit of the thickness is preferably about 50 μm.

[0009] As a resin having a glass transition point of -80 to 20°C for forming an intermediate layer on the surface of the above base sheet,
For example, urea resin (based adhesive), melamine resin (based adhesive), phenolic resin (based adhesive), epoxy resin (
vinyl acetate resin, cyanoacrylate adhesive, polyurethane adhesive, α-olefin-maleic anhydride resin (adhesive), water-based polymer-isocyanate adhesive, reactive acrylic resin adhesive , Modified acrylic resin adhesive, vinyl chloride resin, silicone resin adhesive, polyester resin adhesive, vinyl acetate resin or its copolymer emulsion adhesive, EVA resin emulsion adhesive, acrylic resin adhesive Emulsion type adhesive, polyurethane emulsion type adhesive, styrene-acrylic emulsion type adhesive, natural rubber emulsion, silicone rubber emulsion, chloroprene rubber type (solvent type adhesive), synthetic rubber type (solvent type adhesive)
, synthetic rubber latex adhesives, epoxy resin emulsions, and the like. In addition, the glass transition point is -80℃
If it is lower, the intermediate layer will be too soft and the scratch resistance of the receptor layer surface will be poor, and if the glass transition point exceeds 20°C, the cushioning properties during printing will be insufficient and the printing quality will not be satisfactory. Further, a certain amount of heating is required when manufacturing the image receiving sheet. As a method for forming the intermediate layer, for example,
As a preferred example, first, a receptive layer with a uniform thickness (about 1 to 3 μm when dry) is formed on a polyester film,
Apply the above resin on the sufficiently dried receptor layer to a thickness of 1 to 20μ when dry.
The intermediate layer is formed by applying the mixture to a thickness of about 100 m and drying it. If the intermediate layer is then formed from an aqueous emulsion,
After thoroughly drying the water, press it with the base material of the image-receiving sheet such as paper using a laminating roller or the like (with heating if necessary).
Examples include bonding and a so-called transfer method in which the polyester film is peeled between the film and the receptor layer after bonding, but other methods such as a coating method may also be used, and the present invention is not limited to the manufacturing method.

[0010] In a preferred embodiment of the invention, the above-mentioned intermediate layer includes white pigments, fillers and/or optical brighteners. A method for incorporating these white pigments and the like is to include the white pigments and the like in the coating liquid used when forming the intermediate layer. The purpose of the white pigment or filler is to improve the whiteness and hiding power of the intermediate layer and to prevent the background 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 powdered silica. The amount of these white pigments added varies depending on the type of pigment used, but is generally about 1 to 100 parts by weight per 100 parts by weight of the intermediate layer forming resin.

[0011]Furthermore, the optical brightener improves the whiteness by eliminating the yellowing of the resin in the intermediate layer. Known optical brighteners such as those based on fluorophores, naphthalimides, and thiophenes are used. These optical brighteners are dissolved in the intermediate layer resin and exhibit sufficient effects at extremely low concentrations, for example, from 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. Examples of binder resins for forming the dye-receiving layer include:
Polyolefin resins such as polypropylene, vinyl halide resins such as polyvinyl chloride and polyvinylidene chloride, vinyl resins such as polyvinyl acetate and polyacrylic ester, 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, etc. Particularly preferred are vinyl resins and polyesters. It is a type resin.

The dye-receiving layer in the thermal transfer image-receiving sheet of the present invention is formed by adding, for example, a release agent, an antioxidant, an ultraviolet absorber, etc. to the binder resin as described above on at least one surface of the base sheet. Additives are dissolved in an appropriate organic solvent, or a dispersion in an organic solvent or water is prepared by, for example, gravure printing, screen printing, reverse roll coating using a gravure plate, etc. It is formed by coating and drying using a forming means.

[0014] The dye-receiving layer preferably contains a release agent in order to provide good release properties from the thermal transfer sheet. Preferred mold release agents include silicone oil, phosphate surfactants, fluorine surfactants, and the like, with silicone oil being preferred. The silicone oil is preferably modified with epoxy, alkyl, amino, carboxyl, alcohol, fluorine, alkyl aralkyl polyether, epoxy/polyether, or polyether. One or more types of mold release agents may be used. The amount of the release agent added is preferably 1 to 20 parts by weight per 100 parts by weight of the binder resin. If the amount added does not satisfy this range, problems such as fusion between the thermal transfer sheet and the dye-receiving layer or a decrease 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. Although such a dye-receiving layer is preferably a continuous coating, it may also be formed as a discontinuous coating using a resin emulsion or resin dispersion.

In the present invention, it is preferable to form the dye-receiving layer by a transfer method. That is, when a pulp paper base material is used as the sheet, the surface smoothness may be insufficient, and in this case, the coating method described above may cause unevenness, pinholes, etc. in the dye-receiving layer formed. However, with the transfer method, such problems do not occur. The transfer method includes, for example, forming the above-mentioned dye-receiving layer on the surface of a film with good mold releasability such as a polyester film, and further forming an adhesive layer made of the above-mentioned resin having a glass transition temperature of -80 to 20°C on the surface. This is a method in which the adhesive layer is formed in advance and bonded to the pulp paper base material surface using a laminator or the like, and then the polyester film is peeled off.

In addition, in order to improve the transportability of the image-receiving sheet within the printer, a resin with excellent lubricity such as acrylic resin or acrylic silicone resin, or a suitable lubricity agent is applied to the opposite side 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/m2 by adding rubber particles. The thermal transfer sheet used when performing thermal transfer using the thermal transfer image-receiving sheet of the present invention as described above is one in which a dye layer containing a sublimable dye is provided on paper or polyester film, and conventionally known thermal transfer sheets are All can be used as they are in the present invention. Furthermore, any conventionally known means for applying thermal energy during thermal transfer can be used. For example, the recording time can be controlled by a recording device such as a thermal printer (for example, Video Printer VY-100 manufactured by Hitachi, Ltd.). By doing so, the intended purpose can be fully achieved by applying thermal energy of about 5 to 100 mJ/mm2.

[0017]

[Examples] Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. In the text, parts or percentages are based on weight unless otherwise specified. Example 1 A receptor layer coating solution having the following composition was applied to the surface of a 12 μm thick polyester film (trade name "Lumirror", manufactured by Toray Industries) using a bar coater at a dry rate of 3.0 g/m2. After temporary drying with a dryer, dry in an oven at 100°C for 30 minutes to form a dye-receiving layer, and then apply the following intermediate layer coating solution (adhesive solution) on the receptor layer in the same manner, at a rate of 15g/drying time. An adhesive layer was formed by coating and drying at a ratio of m2 to obtain a receptor layer transfer film used in the present invention. Coating liquid composition for receptor layer: Polyester resin (Vylon 103, manufactured by Toyobo)
100 parts Amino-modified silicone (X-22-343, manufactured by Shin-Etsu Chemical)
Part 3 Epoxy modified silicone (KF
-343, Shin-Etsu Chemical Co., Ltd.) 3 parts methyl ethyl ketone/toluene (weight ratio (1/1)
) 500 parts Coating liquid composition for intermediate layer; Emulsion adhesive (E-1054, glass transition point -50°C, manufactured by Soken Chemical Co., Ltd.)

100
Part White pigment (titanium dioxide, Tochem Products, TCA888) 20 parts Water


30 copies The above receptor layer transfer film was layered on the surface of copy paper (Xerox M paper, thickness 90 μm), and both were passed through a laminator and pasted together, then the base film was peeled off and the dye receptor layer was transferred. A thermal transfer image-receiving sheet of the present invention was obtained.

Example 2 The following intermediate layer coating solution was applied to coated paper at a solid content of 2 g/m2.
After coating and drying at a ratio of
Apply at a ratio of m2, and after temporary drying with a hair dryer, 10
A dye-receiving layer was formed by drying in an oven at 0° C. for 30 minutes to obtain a thermal transfer image-receiving sheet of the present invention. Coating liquid composition for intermediate layer: Acrylic emulsion adhesive (AE-120, glass transition point 0°C, manufactured by Japan Synthetic Rubber)

100 parts white pigment (titanium dioxide, manufactured by Tochem Products, TCA
888) 20 parts water

30 parts Receptive layer coating liquid composition: Vinyl chloride/vinyl acetate copolymer resin (VYHD, manufactured by Union Carbide)


100 parts epoxy modified silicone (KF-393,
(manufactured by Shin-Etsu Chemical) 3 parts Amino-modified silicone (KP343, manufactured by Shin-Etsu Chemical)
Part 3 Methyl ethyl ketone/
Toluene (weight ratio (1/1))
400 copies

Example 3 A coating solution for a receptive layer having the following composition was applied to the surface of a 12 μm thick polyester film (trade name "Lumirror", manufactured by Toray) using a bar coater at a drying rate of 2.0 g/m2. After temporary drying with a dryer, dry in an oven at 100°C for 30 minutes to form a dye-receiving layer, and then apply the following coating solution on the receptor layer in the same manner at a drying rate of 1 g/m2. An intermediate layer was formed by coating and drying to obtain a receptor layer transfer film used in the present invention. Coating liquid 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) 3 parts Amino-modified silicone (KP343, manufactured by Shin-Etsu Chemical)
Part 3 Methyl ethyl ketone/
Toluene (weight ratio (1/1))
400 parts Coating liquid composition for intermediate layer; EVA emulsion adhesive (XC-3940C,
Glass transition point -20℃, manufactured by Toa Paint)

100 parts white pigment (titanium dioxide, manufactured by Tochem Products, TCA8
88) 20 parts water

30 copies The above-mentioned receptor layer transfer film is superimposed on the surface of high-quality paper, and both are pasted together through a laminator, and then the base film is peeled off and the dye-receiving layer and intermediate layer are transferred to form the thermal transfer image receiving layer of the present invention. Got a sheet.

Comparative Example 1 A thermal transfer image-receiving sheet of a comparative example was obtained in the same manner as in Example 1 except that the following thermoplastic resin solution was used as the intermediate layer resin. Vinyl chloride/vinyl acetate copolymer resin (MT3, glass transition point 55°C, manufactured by Denki Kagaku Kogyo)

100 parts methyl ethyl ketone/toluene (weight ratio (1/1))
100 copies 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 in Example 2.

On the other hand, an ink for the dye layer having the following composition was prepared, and applied to a 6 μm thick polyethylene terephthalate film whose back side was heat-resistant treated using a wire bar so that the dry coating amount was 1.0 g/m2, and dried. Then, several drops of silicone oil (X-41.4003A, manufactured by Shin-Etsu Silicone) were dropped on the back surface using a dropper, and the mixture was spread over the entire surface to perform a back treatment coat to obtain a thermal transfer film. 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) 8
0.0 part dioxane

10.0 parts The thermal transfer film was placed on the receiving layer surface of each of the image receiving sheets, and using a thermal head, the output was 1 W/dot and the pulse width was 0.3 to 0.4.
5msec. When a cyan image was formed by printing at a dot density of 3 dots/mm, when the thermal transfer image-receiving sheet of the example was used, the image was of high quality without defective areas such as color loss, but in comparison When the thermal transfer image-receiving sheet of the example was used, defective areas such as color loss were observed and the quality of the image was poor.

[0022]

[Effects] According to the present invention as described above, by forming the intermediate layer from a resin having a glass transition temperature of -80 to 20°C, it is possible to provide a thermal transfer image-receiving sheet with excellent cushioning properties. Further, by adding a white pigment, a filler, a fluorescent whitening agent, etc. to the intermediate layer, the ground color of the base material is hidden, and a dye-receiving layer with high whiteness is formed. Moreover, the above glass transition temperature is -
By forming the image receiving sheet using a receptor layer transfer film with a resin at 80 to 20°C as an adhesive layer (intermediate layer after transfer), even coarse base sheets can be efficiently processed without heating or with simple heating. This enables high-speed transfer.

Claims (4)

[Claims] 1. A thermal transfer method comprising a base sheet and a dye-receiving layer formed on the surface thereof via an intermediate layer, the intermediate layer comprising a resin having a glass transition temperature of -80 to 20°C. Image receiving sheet. 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. [Claim 3]Claim 1, wherein the base sheet is pulp paper.
Thermal transfer image-receiving sheet described in . 4. The thermal transfer image-receiving sheet according to claim 1, wherein the dye-receiving layer is formed by a transfer method.