JPH05286274A - Thermal transfer image receiving sheet - Google Patents

Abstract

PURPOSE:To obtain a thermal transfer image receiving sheet on which an image formed by a thermal transfer system using a sublimable dye can exhibit superior fastnesses, esp. superior light resistance, and in which an ultraviolet light absorber can stably exist in a dye accepting layer without losing its effect in storage. CONSTITUTION:In a thermal transfer image receiving sheet, a dye accepting layer is formed on at least one surface of a substrate sheet, and a layer containing an ultraviolet light absorber is provided between the substrate sheet and the dye accepting layer.

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 to a thermal transfer image-receiving sheet capable of forming a recorded image excellent in color density, vividness and various fastnesses, particularly durability such as light resistance. For the purpose of provision.

[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 a sublimable dye is used as a thermal transfer sheet by supporting it on a base material sheet such as polyester film. There has been proposed a method of forming various full-color images on a dyeable image-receiving sheet, for example, an image-receiving sheet having a dye-receiving layer formed on paper, plastic film or the like. In this case, the thermal head of the printer is used as the heating means, and a large number of three-color or four-color dots are transferred to the image-receiving sheet by heating for an extremely short time, and the full-color image of the original is formed by the multi-color dots. It is to be reproduced. The image formed in this way is
It is very vivid because the coloring material used is a dye,
And because it is excellent in transparency, the obtained image is excellent in reproducibility and gradation of intermediate colors, is similar to the image by conventional offset printing or gravure printing, and has a high quality image comparable to a full color photographic image. It can be formed.

[0003]

[Problems to be solved by the invention] However,
Since the obtained image is formed of a dye, it generally has inferior light resistance as compared with an image formed by a pigment, and there is a problem that the image is rapidly discolored or discolored when exposed to direct sunlight. As a technique for solving the above-mentioned drawbacks, JP-A-60-101
090, JP-A-60-130735, JP-A-61-54982, JP-A-61-229594.
Japanese Patent Laid-Open No. 2-141287 and the like disclose that the dye receiving layer of the 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 is
There is a problem that the ultraviolet absorber bleeds out on the surface of the dye receiving layer and disappears, or is volatilized or decomposed by heat, and the effect of the ultraviolet absorber decreases with time. Further, the fading of the dye image is not only caused by the incident ultraviolet rays, but also ultraviolet rays that pass through the dye receiving layer to reach the base sheet, are reflected by the surface of the base sheet, and are scattered again in the dye receiving layer. Is also promoted by. There is a problem that such fading due to reflected light from the substrate sheet cannot be suppressed by simply adding an ultraviolet absorber on or in the dye receiving layer. Accordingly, an object of the present invention is to provide a formed image having excellent fastnesses, particularly excellent light fastness in a thermal transfer method using a sublimable dye, without losing the effect of the ultraviolet absorber during storage. ,
It is an object of the present invention to provide a thermal transfer image receiving sheet which can be stably present in the dye receiving layer.

[0004]

The above object can be achieved by the present invention described below. That is, the present invention is a thermal transfer image-receiving sheet having a dye receiving layer formed on at least one surface of a base sheet, wherein a layer containing an ultraviolet absorber is provided between the base sheet and the dye receiving layer. Is a thermal transfer image receiving sheet.

[0005]

[Function] By providing a layer containing an ultraviolet absorber between the substrate sheet and the dye receiving layer, a thermal transfer image having excellent light resistance is formed, and the ultraviolet absorber stably receives the dye even during storage. A thermal transfer image-receiving sheet that can be present in the layer can be provided.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the following preferred embodiments. The thermal transfer image-receiving sheet of the present invention has a structure in which an ultraviolet absorber layer and a dye receiving layer are sequentially laminated on a base sheet. Examples of the base sheet used in the present invention include synthetic paper (polyolefin-based, polystyrene-based, etc.), high-quality paper, art paper, coated paper, cast-coated paper, wallpaper, backing paper, synthetic resin or emulsion-impregnated paper, synthetic rubber latex. Films or sheets of various plastics such as impregnated paper, synthetic resin internal paper, paperboard, cellulose fiber paper, polyolefin, polyvinyl chloride, polyethylene terephthalate, polystyrene, polymethacrylate, polycarbonate, etc. can be used, and their synthesis is also possible. 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. Further, a laminated body made of any combination of the above-mentioned substrate sheets can also be used. As an example of a typical laminated body, a synthetic paper of cellulose fiber paper and synthetic paper or cellulose fiber paper and plastic film or sheet can be mentioned. The thickness of these base material sheets may be arbitrary, and for example, a thickness of about 10 to 300 μm is common. The substrate sheet as described above is preferably subjected to a primer treatment or a corona discharge treatment on the surface when the adhesion to the dye receiving layer formed on the surface is poor.

The ultraviolet absorbent layer formed on the surface of the base sheet is for absorbing and blocking the ultraviolet rays transmitted through the dye receiving layer and the ultraviolet rays reflected on the surface of the base sheet. The ultraviolet absorber layer can be formed by applying a coating liquid containing an ultraviolet absorber and a binder resin on the surface of the base material sheet and drying. The binder resin used may be a resin capable of forming a film, such as a thermoplastic resin forming a dye receiving layer described later, and may be a thermosetting resin. Examples of the ultraviolet absorber added to the ultraviolet absorber layer include salicylic acid-based, benzophenone-based, benzotriazole-based, cyanoacrylate-based ultraviolet absorbers, and more specifically, phenyl salicylate and P-octylphenyl-. Salicylate, P
-T-butylphenyl salicylate, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxy-benzophenone, 2,2'-dihydroxy-4,4 '
-Dimethoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxy-5-sulfonebenzophenone, 2-hydroxy-4-n-octoxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, 2- (2'- Hydroxy-3 ', 5'-di-t-butyl-phenyl) -benzotriazole, 2- (2'-
Hydroxy-3'-t-butyl-5'-methyl-phenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3 ', 5'-di-t-butyl-phenyl)-
5-chlorobenzotriazole, 2- (2'-hydroxy-4'-n-octoxyphenyl) benzotriazole, ethyl-2-cyano-3,3-diphenylacrylate and the like can be mentioned.

The ultraviolet absorbent layer is a dispersion prepared by dissolving the ultraviolet absorbent and other necessary additives in a suitable binder resin in a suitable organic solvent or dispersing it in an organic solvent or water. Is applied, dried and heated by a forming means such as a gravure printing method, a screen printing method and a reverse roll coating method using a gravure plate. The thickness of the ultraviolet absorbent layer is 0.05
The range of μm to 5 μm is appropriate, and the effective amount of the ultraviolet absorber added is determined by the thickness of the ultraviolet absorber layer and the kind of the compound, and the volume ratio of the ultraviolet absorber is 0.1%.
It gives good results when added in the range of -30%.

The dye receiving layer formed on the surface of the ultraviolet absorbent layer is for receiving the sublimable dye transferred from the thermal transfer sheet and maintaining the formed image. As the resin for forming the dye receiving layer, for example, polyolefin resin such as polypropylene, polyvinyl chloride,
Halogenated polymers such as polyvinylidene chloride, polyvinyl acetate, vinyl polymers such as polyacrylic ester, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polystyrene resins, polyamide resins, olefins such as ethylene and propylene, and other Examples thereof include copolymer resins with vinyl monomers, ionomers, cellulose resins such as cellulose diacetate, polycarbonates, and the like, and vinyl resins, polycarbonate resins, and polyester resins are particularly preferable.

The thermal transfer image-receiving sheet of the present invention is prepared by dissolving at least one surface of the above-mentioned base material sheet, in which an additive such as a releasing agent is added to the resin as described above, in a suitable organic solvent or by using an organic solvent. A dispersion dispersed in a solvent or water, for example,
It can be obtained by forming a dye receiving layer by coating, drying and heating 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 forming the dye receiving layer, pigments or fillers 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 and further enhancing the sharpness of the transferred image. Agents can be added. The dye-receptive 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 it may be formed as a discontinuous coating by using a resin emulsion or resin dispersion.

Further, the image-receiving sheet of the present invention can be applied to various applications such as a heat-transferable sheet capable of thermal transfer recording, cards and a transmission type original preparation sheet by appropriately selecting a substrate sheet. Furthermore, 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, there is little noise during printing and image information can be dealt with. The recorded image can be transferred and recorded with good reproducibility.
Examples of the material forming 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. Also, a slipping layer can be provided on the back surface of the base material sheet. The material of the slipping layer may be a methacrylate resin such as methyl methacrylate or a corresponding acrylate resin, vinyl chloride-
Examples thereof include vinyl resins such as vinyl acetate copolymer.
Further, it is 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, and for example, the detection mark that can be detected by the photoelectric tube detection device can be provided on the back surface of the base material 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 a sheet in which a dye layer containing a sublimable dye is provided on a paper or a polyester film, and is conventionally known. Any thermal transfer sheet can be used as it is in the present invention. Further, as the means for applying the 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 thermal energy of about 5 to 100 mJ / mm ^2. I can.

[0013]

EXAMPLES Next, the present invention will be described more specifically with reference to Examples and Comparative Examples. In the text, “part” or “%” is based on weight unless otherwise specified. Example 1 Synthetic paper (Yupo FRG-150, thickness 1
50 μm, manufactured by Oji Yuka Co., Ltd., and one side of which is coated with a coating solution having the following composition by a bar coater to give 3.0 g / m
^The ultraviolet absorbent layer was formed by coating and drying at a ratio of ² . Coating solution composition: Polycarbonate resin of the following structural formula 10.0 parts UV absorber of the following structural formula 3.0 parts Chloroform 90.0 parts

[0014]

[Chemical 1]

[Chemical 2] Next, a coating solution having the following composition was applied to the surface of the formed ultraviolet absorbent layer by a bar coater to give a film thickness of 2.0 μm when dried.
The dye-receptive layer was formed by coating and drying at a ratio of m to obtain a thermal transfer image-receiving sheet of the present invention. Coating liquid composition: Polyester resin (Vylon 200, manufactured by Toyobo) 10.0 parts Catalyst crosslinkable silicone (X-62-1212, manufactured by Shin-Etsu Chemical Co., Ltd.) 1.0 part Platinum-based catalyst (PL-50T, Shin-Etsu Chemical Co., Ltd.) Made) 0.1 part Methyl ethyl ketone / toluene (weight ratio 1/1) 90.0 parts

Example 2 A thermal transfer image-receiving sheet of the present invention was obtained in the same manner as in Example 1 except that the ultraviolet absorber of the following structural formula was used in place of the ultraviolet absorber in Example 1.

[Chemical 3] Example 3 A thermal transfer image-receiving sheet of the present invention was obtained in the same manner as in Example 1, except that the ultraviolet absorber of the following structural formula was used instead of the ultraviolet absorber in Example 1.

[Chemical 4]

Example 4 A thermal transfer image-receiving sheet of the present invention was obtained in the same manner as in Example 1 except that the ultraviolet absorber of the following structural formula was used in place of the ultraviolet absorber in Example 1.

[Chemical 5] Example 5 A thermal transfer image-receiving sheet of the present invention was obtained in the same manner as in Example 1, except that the ultraviolet absorber of the following structural formula was used instead of the ultraviolet absorber in Example 1.

[Chemical 6]

Example 6 A thermal transfer image-receiving sheet of the present invention was obtained in the same manner as in Example 1 except that the ultraviolet absorber of the following structural formula was used instead of the ultraviolet absorber in Example 1.

[Chemical 7]

Comparative Example 1 A thermal transfer of Comparative Example was carried out by coating a coating solution having the following composition on one surface of the same substrate sheet as in Example 1 with a bar coater at a rate such that the film thickness when dried was 5 μm, and drying. An image receiving sheet was obtained. Coating liquid composition: Polyester resin (Vylon 200, manufactured by Toyobo) 10.0 parts Catalyst crosslinkable silicone (X-62-1212, manufactured by Shin-Etsu Chemical Co., Ltd.) 1.0 part Platinum thread catalyst (PL-50T, Shin-Etsu Chemical Co., Ltd.) 0.1 parts Methyl ethyl ketone / toluene (weight ratio 1/1) 90.0 parts On the other hand, a 6 μm-thick polyethylene terephthalate film prepared by preparing an ink composition for forming a dye-carrying layer having the following composition and subjecting the back surface to heat treatment And a dry coating amount of 1.0 g / m ²
And then dried by gravure printing to obtain a thermal transfer sheet used in the present invention. Ink composition; cyan dye of the following structural formula 3 parts Polyvinyl butyral resin (S-REC BX-1, manufactured by Sekisui Chemical Co., Ltd.) 4 parts Methyl ethyl ketone 50 parts Toluene 43 parts

[0019]

[Chemical 8] Thermal transfer test: The thermal transfer sheet and the thermal transfer image-receiving sheet of the present invention and the comparative example are superposed with their dye layers and dye receiving surfaces facing each other, and a thermal head is used from the backside of the thermal transfer sheet. Applied voltage 11.0 V, applied pulse width 16 msec. / Line to 1 msec.
Step pattern that decreases sequentially for each, 6l in the sub-scanning direction
After recording with a thermal head under the condition of ine / mm (33.3 msec./line) to form a magenta and cyan image, the light resistance and storability of both were examined, and the results shown in Table 1 below were obtained. In addition, the evaluation method of each performance shown in Table 1 was performed as follows.

(1) Light fastness test method The printed matter was measured with a xenon fade odometer (Ci-35A, manufactured by Atlas Co.) at 400 KJ / m ² and 500 K.
Irradiation with J / m ² was performed, and the change in optical density before and after irradiation was measured with an optical densitometer (RD-918, manufactured by Macbeth Co.), and the residual ratio of optical density was calculated by the following formula. Residual rate (%) = {[optical density after irradiation] / [optical density before irradiation]} × 100 ◎; residual rate is 70% or higher ○: residual rate is 60% or higher and lower than 70% Δ; residual rate is 50 % Or more and less than 60% ×; residual rate is 40% or more and less than 50% XX; residual rate is less than 40%

(2) Spectral reflectance of thermal transfer image receiving sheet A Shimadzu self-recording spectrophotometer UV-240 was fitted with an integrating sphere accessory device (inner type 60 mmφ, with photomultiplier tube R928) in the sample chamber, and the base material of the thermal transfer image receiving sheet. The spectral reflectance of the light reflected from the sheet was measured.

[0022]

[Table 1]

[0023]

[Effects] According to the present invention as described above, by providing a layer containing an ultraviolet absorber between the base sheet and the dye receiving layer, a thermal transfer image having excellent light resistance can be formed, and further during storage. It is also possible to provide a thermal transfer image-receiving sheet in which the ultraviolet absorber can be stably present in the dye receiving layer.

Claims (1)

[Claims] 1. A thermal transfer image-receiving sheet having a dye-receiving layer formed on at least one surface of a base sheet, wherein a layer containing an ultraviolet absorber is provided between the base sheet and the dye-receiving layer. A thermal transfer image-receiving sheet characterized by.