JP3325613B2 - 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 capable of forming a recorded image excellent in durability such as color density, sharpness and various fastnesses, particularly light fastness. For the purpose of providing.

[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 an 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 the image receiving sheet by heating for a very short time, and a full-color image of an original is formed by the multicolored dots. That 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]

[Problems to be solved by the invention]
Since the resulting image is formed from a dye, it generally has poor light fastness as compared with an image using a pigment, and has a problem that the image is rapidly faded or discolored when exposed to direct sunlight. JP-A-60-101 discloses a technique for solving the above-mentioned disadvantages.
090, JP-A-60-130735, JP-A-61-54982, JP-A-61-229594.
And JP-A-2-141287 disclose that a dye-receiving layer of a thermal transfer image-receiving sheet contains an ultraviolet absorber or an antioxidant. Although the light resistance is improved to some extent by adding an ultraviolet absorber, the method of simply adding the ultraviolet absorber to the dye-receiving layer involves:
There is a problem in that the ultraviolet absorber bleeds out to the surface of the dye receiving layer and disappears, or is volatilized or decomposed by heat, so that the effect of the ultraviolet absorber decreases with time. Therefore, an object of the present invention is, in a thermal transfer method using a sublimable dye, the formed image is excellent in various fastnesses,
An object of the present invention is to provide a thermal transfer image-receiving sheet which exhibits particularly excellent light fastness and can be stably present in the dye-receiving layer without losing the effect of the ultraviolet absorber during storage.

[0004]

The above object is achieved by the present invention described below. That is, the present invention provides a thermal transfer image-receiving sheet having a dye-receiving layer formed on at least one surface of a substrate sheet, wherein the dye-receiving layer has the following general formula [I]
A thermal transfer image-receiving sheet comprising at least one compound represented by the formulas (III) to (III):

[0005]

Embedded image (R ₁ and R ₂ in the above formula are linear or branched
Alkyl group, hydrogen atom, hydroxyl group or C ₁ -C ₈ alkoxy
Group. )

[0006]

By including an ultraviolet absorber having a specific structure in the dye receiving layer, a heat transfer image having excellent light fastness is formed, and the ultraviolet absorber is stably present in the dye receiving layer even during storage. The resulting thermal transfer image-receiving sheet can be provided.

[0007]

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 comprises a base sheet and a dye receiving layer formed on at least one surface of the base sheet. 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, synthetic resin paper, 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 these synthetic resins or a foamed foam sheet can also be used, and there is no particular limitation. 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 base sheets may be arbitrary, and for example, a thickness of about 10 to 300 μm is generally used. 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.

[0008] 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 the resin for forming the dye receiving layer include polyolefin resins such as polypropylene, halogenated polymers such as polyvinyl chloride and polyvinylidene chloride, vinyl polymers such as polyvinyl acetate and polyacrylester, polyethylene terephthalate, and poly (ethylene terephthalate). Polyester resins such as butylene terephthalate, polystyrene resins, polyamide resins, copolymer resins of olefins such as ethylene and propylene and other vinyl monomers, ionomers, cellulose resins such as cellulose diacetate, and polycarbonate. Particularly preferred are vinyl resins, polycarbonate resins and polyester resins. The ultraviolet absorber you added to the dye-receiving layer in the present invention, represented by the following following general formula [I] ~ [III]
Compounds .

[0009]

Embedded image

In the above formula, R ₁ and R ₂ are a linear or branched alkyl group, a hydrogen atom, a hydroxyl group or a C ₁ -C ₈ alkoxy group .

The ultraviolet absorber is preferably used in an amount of 1 to 20% by weight, more preferably 5 to 10% by weight, based on the solid content of the resin forming the dye receiving layer.
If the amount used is less than 1% by weight, satisfactory light resistance is difficult to obtain, while if it exceeds 20% by weight, the surface of the dye-receiving layer becomes sticky and the heat-transferred image is undesirably soiled. The compounds represented by the general formulas [ I] to [III] are all useful in the present invention.
1 is represented by those substituents.

[0012]

[Table 1]

[0013]

The thermal transfer image-receiving sheet of the present invention is obtained by adding at least one surface of the above-mentioned base sheet to the above-mentioned resin and the above-mentioned additives such as an ultraviolet absorber and a release agent in an appropriate organic solvent. Dispersed or dispersed in an organic solvent or water, for example, gravure printing, screen printing,
It is obtained by applying, drying and heating by a forming means such as a reverse roll coating method using a gravure plate to form a dye receiving layer. In the formation of the dye-receiving layer, pigments such as titanium oxide, zinc oxide, kaolin clay, calcium carbonate, and finely powdered silica are used for the purpose of improving the whiteness of the dye-receiving layer to further enhance the sharpness of the transferred image. Agents can be added. The dye-receiving layer formed as described above may have any thickness, but is generally 1 to 5
The thickness is 0 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.

The image-receiving sheet of the present invention can be applied to various uses such as a heat-transferable recordable sheet, cards, and a sheet for making a transmission type original by appropriately selecting a base sheet. Further, the image receiving sheet of the present invention can be provided with a cushion layer between the base sheet and the dye receiving layer, if necessary. By providing such a cushion layer, noise during printing can be reduced and the image information can be handled. The transferred image can be transferred and recorded with good reproducibility. Examples of the material constituting the cushion layer include polyurethane resin, acrylic resin, polyethylene resin, butadiene rubber, and epoxy resin. The thickness of the cushion layer is preferably about 2 to 20 μm.

Further, a lubricating layer may be provided on the back surface of the base sheet. Examples of the material of the lubricating layer include a methacrylate resin such as methyl methacrylate or a corresponding acrylate resin, and a vinyl resin such as a vinyl chloride-vinyl acetate copolymer. Furthermore, it is also possible to provide a detection mark on the image receiving sheet. The detection mark is extremely convenient when positioning the thermal transfer sheet and the image receiving sheet. For example, a detection mark that can be detected by a photoelectric tube detection device can be provided on the back surface of the base sheet by printing or the like.

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. Any thermal transfer sheet can be used as it is in the present invention. As a means for applying thermal energy at the time of thermal transfer, any conventionally known applying means can be used. For example, a thermal printer (for example,
By controlling the recording time with a recording device such as a video printer VY-100 manufactured by Hitachi, Ltd., it is possible to sufficiently achieve the intended purpose by applying heat energy of about 5 to 100 mJ / mm ^2. I can do it.

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.

Example 1 A synthetic paper (Yupo FRG-150, thickness 1) was used as a base sheet.
50 μm, manufactured by Oji Yuka Co., Ltd.), and a coating solution having the following composition was dried on one surface thereof with a bar coater at a time of 5.0 g / m 2.
Coating and drying were performed at a ratio of ² to form a dye-receiving layer, whereby thermal transfer image-receiving sheets of the present invention and comparative examples were obtained. Coating liquid composition; polycarbonate resin (CAM1035, manufactured by Mitsubishi Gas Chemical) 10.0 parts Catalyst cross-linked silicone (X-62-1212, manufactured by Shin-Etsu Chemical) 1.0 part Platinum-based catalyst (PL-50T, Shin-Etsu Chemical) 0.1 part Compound in Table 1 1.0 part Methyl ethyl ketone / toluene (weight ratio 1/1) 90.0 parts On the other hand, an ink composition for forming a dye-carrying layer having the following composition was prepared and heat-treated on the back surface. Was applied to a 6 μm-thick polyethylene terephthalate film having a dry coating amount of 1.0 g / m ^2.
Was applied by gravure printing and dried to obtain a thermal transfer sheet used in the present invention.

Ink composition: Magenta dye of the following structural formula 3 parts Polyvinyl butyral resin (S-lek BX-1, manufactured by Sekisui Chemical Co., Ltd.) 4 parts Methyl ethyl ketone 50 parts Toluene 43 parts

Embedded image

Example 2 A synthetic paper (Yupo FRG-150, thickness 1) was used as a base sheet.
50 μm, manufactured by Oji Yuka Co., Ltd.), and a coating solution having the following composition was dried on one surface thereof with a bar coater at a time of 5.0 g / m 2.
Coating and drying were performed at a ratio of ² to form a dye-receiving layer, whereby thermal transfer image-receiving sheets of the present invention and comparative examples were obtained. Coating liquid composition; polyester resin (GXP-23, manufactured by Toyobo Co., Ltd.) 10.0 parts Catalyst cross-linkable silicone (X-62-1212, manufactured by Shin-Etsu Chemical Co., Ltd.) 1.0 part Platinum-based catalyst (PL-50T, Shin-Etsu Chemical) (Manufactured by Kogyo Co., Ltd.) 0.1 part Compound in Table 1 1.0 part Chloroform 90.0 parts

On the other hand, an ink composition for forming a dye-carrying layer having the following composition was prepared, and gravure was applied to a 6 μm-thick polyethylene terephthalate film whose back surface was heat-treated so that the dry coating amount was 1.0 g / m ^2. It was applied and dried by printing to obtain a thermal transfer sheet used in the present invention. Ink composition: Cyan dye having the following structural formula 3 parts Polyvinyl butyral resin (S-LEC BX-1, manufactured by Sekisui Chemical Co., Ltd.) 4 parts Methyl ethyl ketone 50 parts Toluene 43 parts

Embedded image

Thermal transfer test : The above-mentioned thermal transfer sheet and the above-mentioned thermal transfer image-receiving sheet of the present invention are superposed on each other with the respective dye layers and the dye-receiving surface facing each other.
Head applied voltage 11.0V, applied pulse width 16mse
c. 1msec./line. A step pattern that is sequentially reduced every time, 6 line / mm in the sub-scanning direction (33.
3 msec. After recording was performed with a thermal head under the condition of (/ line) to form magenta and cyan images, the light resistance of both was examined, and the results in Tables 3 and 4 below were obtained.

Light fastness test method: The printed matter was measured at 300 KJ / m ² or 200 K using a xenon fadeometer (Ci-35A, manufactured by Atlas).
Irradiation was performed at J / m ² , and the change in optical density before and after irradiation was measured with an optical densitometer (RD-918, manufactured by Macbeth), and the residual ratio of optical density was calculated by the following equation. Residual rate (%) = {[optical density after irradiation] / [optical density before irradiation]} × 100 ◎; residual rate is 80% or more ○; residual rate is 70% or more and less than 80% △; residual rate is 60 % Or more and less than 70% ×: Residual rate is less than 60%

Comparative Example 1 In the same manner as in Example 1 except that the ultraviolet absorbers 1 to 4 of the following Comparative Examples were used in the same amounts instead of the compounds added to the coating solution for the image receiving layer of Example 1, The results in Table 5 below were obtained. Comparative Example 2 In place of the compound added to the coating solution for an image receiving layer of Example 2, the same amount of each of the ultraviolet absorbers 1 to 4 of the following Comparative Example was used, and the other conditions were the same as in Example 2 except for the following Table 6. Was obtained.

[0025]

Embedded image

[0026]

[Table 3] (Example 1)

[0027]

[Table 4] (Example 2)

[0028]

[Table 5] (Comparative Example 1)

[0029]

Table 6 (Comparative Example 2)

[0030]

According to the present invention as described above, various ultraviolet absorbers, antioxidants, light stabilizers, and the like were examined for light fastness and other preservability of a sublimation transfer image obtained by thermal transfer. in the structural formula [I] ~ thermal transfer image-receiving sheet provided with a receptive layer containing an ultraviolet absorber of benzoyl methane induction system represented by [III], the dye-receiving during storage as well as light resistance of the sublimable dye image The stability of the UV absorber in the layer is significantly better than other UV absorbers.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-229594 (JP, A) JP-A-63-101372 (JP, A) JP-A-2-289530 (JP, A) JP-A-2- 1387 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B41M 5/38-5/40

Claims (1)

(57) [Claims] 1. A thermal transfer image-receiving sheet having a dye-receiving layer formed on at least one surface of a base sheet, wherein the dye-receiving layer is at least one of compounds represented by the following general formulas [I] to [III]: A thermal transfer image-receiving sheet comprising: Embedded image (R ₁ and R ₂ in the above formula are linear or branched
Alkyl group, hydrogen atom, hydroxyl group or C ₁ -C ₈ alkoxy
Group. )