JP3274884B2 - 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 provide a thermal transfer image-receiving sheet capable of forming a recorded image having excellent color density and sharpness with high productivity.

[0002]

2. Description of the Related Art Conventionally, various thermal transfer methods are known. Among them, a sublimable dye is used as a recording agent, and this is carried on a base sheet such as a polyester film to form a thermal transfer sheet. Dyeable transfer material, for example,
There have been proposed methods of forming various full-color images on a thermal transfer image-receiving sheet having a dye-receiving layer formed on paper, plastic film, or the like. 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 a full-color image of an original is formed by the multicolored dots. Is to reproduce. The image formed in this way is very clear because the coloring material used is a dye, and is excellent in transparency, so that the obtained image is excellent in the reproducibility and gradation of intermediate colors. It is possible to form a high-quality image which is similar to an image by offset printing or gravure printing, and is comparable to a full-color photographic image.

[0003]

In order to effectively carry out the above-described thermal transfer method, not only the structure of the thermal transfer sheet but also the structure of the thermal transfer image receiving sheet for forming an image is important. Conventionally, the thermal transfer image-receiving sheet is provided with a primer layer (adhesive layer), a bubble-containing layer (cushion layer), and / or an intermediate layer as necessary on the surface of the base sheet, and a dye-receiving layer as an essential layer thereon. It is manufactured by forming a layer. Alternatively, a dye-receiving layer is formed on the surface of the base film in a releasable manner, and if necessary, an intermediate layer, a bubble-containing layer and / or an adhesive Preparation of a dye-receiving layer transfer film having layers formed thereon, bonding the adhesive layer of the film to the surface of the substrate sheet of the thermal transfer image-receiving sheet, and then peeling off the substrate film. Can be done. In any of the above methods, when a resin layer is formed on a base sheet or a base film, a coating liquid obtained by dissolving or dispersing necessary components in a general-purpose organic solvent having good volatility (dryability) is used. Each coating solution is prepared and applied to the surface of a base sheet or a base film and dried to form a required resin layer. In this case, it is not desirable that the organic solvent remains in the formed resin layer, and the organic solvent must be removed by drying as much as possible. However, it takes a considerable temperature and a relatively long time to sufficiently remove the organic solvent from the resin layer. Therefore, there is a problem that the resin of the formed resin layer is deteriorated. There is a problem that it is not possible to increase the productivity of the thermal transfer image-receiving sheet because it takes time. The above problems can be solved by using an organic solvent having a very low boiling point as the organic solvent, but in the case of these special solvents, it is difficult to prepare a coating solution,
Further, the uniformity of the formed layer is hindered, and there is a problem in the stability of the product, and there is a problem that the density of the printed image changes . There is a risk of health or fire, etc. top of its, in fact is not possible use. Accordingly, an object of the present invention is to provide a thermal transfer image-receiving sheet that provides a clear image having a sufficient density with high productivity in a thermal transfer method using a sublimable dye.

[0004]

The above object is achieved by the present invention described below. That is, the present invention provides at least one surface of the base sheet from at least a polyester resin.
A dye receiving layer, and ethylene glycol is provided in the dye receiving layer.
Cold dibutyl ether or ethylene glycol butyl
A thermal transfer image receiving sheet, characterized in that it contains ether acetate 3 to 20 wt%.

[0005]

When a resin layer containing at least a dye receiving layer is formed from a coating solution containing an organic solvent, a specific high-boiling organic solvent which is non-volatile at room temperature is added to the coating solution. When the coating liquid is applied and dried, the evaporation rate of the volatile solvent is remarkably accelerated, the formation of the resin layer is completed in a short time, and a thermal transfer image-receiving sheet can be provided with extremely high productivity. Although a high-boiling organic solvent remains in the formed resin layer to some extent, by appropriately adjusting the amount of the residual solvent, the coloring density of the dye during transfer of the dye is remarkably improved.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to preferred embodiments. The thermal transfer image-receiving sheet of the present invention can be obtained by forming a resin layer containing at least a dye-receiving layer on at least one surface of a base sheet, and making the resin layer contain a high-boiling organic solvent. Hereinafter, an example in which a high-boiling organic solvent is contained in the dye receiving layer will be described as a typical example. 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 also be used, and is not particularly limited. Also, a laminate formed by any combination of the above base sheets can be used. Examples of typical laminates include synthetic paper of cellulose fiber paper and synthetic paper or cellulose fiber paper and plastic film or sheet. The thickness of these substrate sheets may be arbitrary, for example, 10 to 30
A thickness of about 0 μm is common. When the substrate sheet as described above has poor adhesion to the dye-receiving layer formed on its surface, it is preferable to apply a primer treatment or a corona discharge treatment to its surface.

The dye-receiving layer formed on the surface of the base sheet is for receiving a sublimable dye transferred from the thermal transfer sheet and maintaining the formed image. As the thermoplastic resin for forming the dye-receiving layer, positive Riechire <br/> terephthalate, polybutylene terephthalate polyester resins can be cited for.

[0008] Examples of the high-boiling organic solvent used in the present invention, e Chi glycol dibutyl ether, ethylene glycol butyl ether acetate tape and. The content of these high-boiling organic solvents is preferably from 3 to 20% by weight of the resin layer and the proportion remaining in the dye-receiving layer. If the amount used is too small, the evaporation rate of the volatile organic solvent is not sufficient during drying of the dye receiving layer coating solution,
If the amount is too large, the strength of the dye receiving layer decreases, and
It is not preferable because blurring or the like occurs in the formed image.
The thermal transfer image-receiving sheet of the present invention, on at least one surface of the base sheet, a high-boiling organic solvent for the thermoplastic resin as described above, and other necessary additives, for example, a release agent, a crosslinking agent, A mixture containing a curing agent, a catalyst, a heat release agent, an ultraviolet absorber, an antioxidant, and a light stabilizer is added to a suitable organic solvent, for example, a general-purpose organic solvent such as toluene, methyl ethyl ketone, or a mixture thereof. It is obtained by forming a dye receiving layer by applying and drying the dissolved or dispersed coating liquid by a forming means such as a gravure printing method, a screen printing method, and a reverse roll coating method using a gravure plate.

In the formation of the dye receiving layer, titanium oxide, zinc oxide, kaolin clay, calcium carbonate, fine powder silica, etc. are used for the purpose of improving the whiteness of the dye receiving layer to further enhance the sharpness of the transferred image. Pigments and fillers can be added. 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 can be formed by a transfer method. That is, for example, when pulp paper or the like is used as the base sheet,
The substrate may have insufficient surface smoothness, and in this case, irregularities or pinholes may be generated in the dye receiving layer formed by the coating method, but according to the transfer method,
Such a problem does not occur.

In the transfer method, for example, the above-mentioned dye-receiving layer is formed on the surface of a film having good releasability, such as a polyester film, and an appropriate pressure-sensitive adhesive layer or adhesive layer is further formed on the surface thereof. This is a method in which the pressure-sensitive adhesive layer is bonded to a base sheet surface of the pulp paper or the like with a laminator or the like, and then the polyester film is peeled. or,
When the intermediate layer is formed, the intermediate layer may be formed on the surface of the base sheet in advance, or may be provided on the surface of the dye receiving layer of the dye receiving layer transfer sheet. As described above, the present invention has been described with an example in which a high-boiling organic solvent is added to the dye-receiving layer. However, the thermal transfer image-receiving sheet of the present invention may further comprise a primer layer (adhesive layer), a cushion layer (bubble-containing layer), an intermediate layer, and the like. When other layers are included, these layers can also contain a high-boiling organic solvent to similarly improve the drying rate of these layers. The thermal transfer image-receiving sheet of the present invention can be applied to various uses such as a sheet- or roll-shaped thermal transfer image-receiving sheet, cards, and a transmissive original sheet by appropriately selecting a base sheet. You can do it. Further, the thermal transfer image-receiving sheet of the present invention can be provided with a cushion layer between the base sheet and the dye receiving layer as needed, and by providing such a cushion layer, noise during printing is reduced and image information is reduced. A corresponding image can be transferred and recorded with good reproducibility. The thermal transfer sheet used when performing thermal transfer using the thermal transfer image-receiving sheet of the present invention as described above is provided with a dye layer containing a sublimable dye on paper or polyester film. Any of them can be used as it is in the present invention.

As the means for applying thermal energy at the time of thermal transfer, any conventionally known applying means can be used. For example, a recording apparatus such as a thermal printer (for example, a video printer VY-100 manufactured by Hitachi, Ltd.) or the like can be used. By controlling the recording time,
By applying heat energy of about 00 mJ / mm ² , the intended purpose can be sufficiently achieved.

Next, the present invention will be described more specifically with reference to examples and comparative examples. In the following description, parts or% are based on weight unless otherwise specified. Reference Example 1 A synthetic paper (manufactured by Oji Yuka, thickness 110 μm) was used as the base sheet.
m), a coating liquid having the following composition was applied to one surface of the coating with a wire bar at a rate of 5.0 g / m ² when dried, and a thermal transfer image-receiving sheet of Reference Example was obtained. Coating liquid composition; polyester resin (Vylon 600, manufactured by Toyobo) 100 parts Amino-modified silicone (KF-393, manufactured by Shin-Etsu Chemical) 3 parts Epoxy-modified silicone (X-22-343, manufactured by Shin-Etsu Chemical) 3 parts High boiling point Organic solvent (dioctyl adipate) 15 parts Methyl ethyl ketone / toluene (1/1 by weight) 900 parts

[0012]

[0013] Using the ethylene glycol dibutyl ether in the same amount instead of the high-boiling organic solvent in Example 1 Reference Example 1, another reference example 1
In the same manner as in the above, a thermal transfer image-receiving sheet of the present invention was obtained. Example 2 The same amount of ethylene glycol monobutyl ether acetate was used in place of the high boiling point organic solvent in Reference Example 1,
Otherwise in the same manner as in Reference Example 1, a thermal transfer image-receiving sheet of the present invention was obtained.

[0014]

[0015] Instead of the coating liquid of Comparative Example 1 Reference Example 1 using the coating solution of the following other to obtain a thermal transfer image-receiving sheet of Comparative Example in the same manner as in Reference Example 1. Coating solution composition: polyester resin (Vylon 600, manufactured by Toyobo) 100 parts Amino-modified silicone (KF-393, manufactured by Shin-Etsu Chemical) 3 parts Epoxy-modified silicone (X-22-343, manufactured by Shin-Etsu Chemical) 3 parts Methyl ethyl ketone / Toluene (weight ratio 1/1) 900 parts The drying speed at the time of producing the thermal transfer image-receiving sheet of the present invention and the comparative example was measured under the following conditions, and the results were shown in Table 1 below.
It was shown to. Drying speed test; After 5 seconds hot air from a distance of 20cm and cold air against 5 seconds using a commercial dryer 1,200 W, measured gas chromatograph (GC-14A, manufactured by Shimadzu Corporation Seiki) by. Measurements is the total amount of the methylol Rue ethyl ketone and toluene. On the other hand, an ink composition for forming a dye-carrying layer having the following composition was prepared, and a 6 μm-thick polyethylene terephthalate film having a heat-treated rear surface with a dry coating amount of 1.
It was applied and dried with a wire bar so as to be 0 g / m ² to obtain a thermal transfer sheet. Ink composition; I. Disperse Blue 24 1.0 part Polyvinyl butyral resin 10.0 parts Methyl ethyl ketone / toluene (weight ratio 1/1) 90.0 parts

Thermal transfer test: The above-mentioned thermal transfer sheet and the thermal transfer image-receiving sheet of the present invention and the comparative example are overlapped with their respective dye layers and the dye-receiving surface facing each other, and a thermal head is used from the back of the thermal transfer sheet. And a head applied voltage of 11.0 V and an applied pulse width of 1
6 msec. 1msec./line. Step pattern to be sequentially reduced every time, 6 line / mm in the sub-scanning direction
(33.3 msec./line) After recording with a thermal head under the condition of forming a cyan image, the color density and sharpness of both were examined, and the results in Table 1 below were obtained. (1) Evaluation method of color density : Relative comparison of print density (OD measurement value by Macbeth RD918) in a step of an applied pulse width of 8 ms in a thermal transfer test was performed, and a comparative example was set to 100%.

[0017]

[Table 1]

[0018]

According to the present invention as described above, when a resin layer containing at least a dye-receiving layer is formed from a coating solution containing an organic solvent, a specific high-boiling organic compound which is non-volatile at room temperature is contained in the coating solution. By adding the solvent, the evaporation rate of the volatile solvent is remarkably accelerated when the coating liquid is applied and dried, the formation of the resin layer is completed in a short time, and the thermal transfer image receiving sheet is extremely produced. It can be provided well. The high-boiling point organic solvent remains in the formed resin layer. By appropriately adjusting the amount of the remaining organic solvent, the coloring density of the dye during transfer of the dye is remarkably improved.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Shino Takao 1-1-1 Ichigaya-Kaga-cho, Shinjuku-ku, Tokyo Inside Dai Nippon Printing Co., Ltd. (56) References JP-A-60-25793 (JP, A) JP-A-4-1222693 (JP, A) JP-A-3-224794 (JP, A) JP-A-3-13389 (JP, A) JP-A-61-274990 (JP, A) Int.Cl. ⁷ , DB name) B41M 5/38-5/40

Claims (1)

(57) [Claims] 1. A dye receiving layer comprising at least a polyester resin is provided on at least one surface of a substrate sheet ,
Ethylene glycol dibutyl ether in the dye receiving layer
Or 3 parts of ethylene glycol butyl ether acetate
A thermal transfer image-receiving sheet, characterized in that it contains about 20% by weight .