JP2825778B2 - Image receiving sheet for thermal transfer recording - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image receiving sheet for thermal transfer recording. More specifically, the present invention relates to an image-receiving sheet for thermal transfer recording, which has excellent fixability of a recorded image and can prevent discoloration due to aging.

[0002]

2. Description of the Related Art A sublimation type thermal transfer using a thermal transfer sheet having a color material layer containing a thermal sublimation type dye and a thermal transfer recording image receiving sheet receiving the sublimation dye sublimated from the back surface of the thermal transfer sheet by heating a thermal head. The recording method has attracted attention as providing a color hard copy close to a color photograph having excellent gradation reproducibility. At present, the mainstream of thermal transfer recording sheets is a sheet in which a dye receiving layer is formed on one side of a composite sheet in which the same type of synthetic paper or a foamed polypropylene sheet is laminated on both sides of a base paper. However, the recorded image using the thermal transfer recording sheet has poor fixability of the dye thermally transferred to the dye receiving layer, and is a part touched by hand or a part on which an eraser is placed or stored in a high humidity environment. Has a drawback that the dye tends to discolor over time due to the dissolution of the dye over time due to the plasticizer and moisture contained in the hand fat and the eraser. In addition, there is a problem that the visibility is deteriorated due to poor light fastness of the recorded image over time, and the durability of the recorded image surface is poor due to rubbing and scratching.

[0003]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems such as the fixability of a recorded image on an image receiving sheet for thermal transfer recording, image fading and aging over time, and a color photograph in which a recorded image is always stable. It is an object of the present invention to provide an image receiving sheet for thermal transfer recording which has a color / tone value close to that of the above and has excellent surface strength.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a thermal transfer having a dye-receiving layer for receiving a sublimation dye transferred from a thermal transfer sheet by heating on a base paper. An image receiving sheet for recording,
There is a cushion layer between the base paper and the dye-receiving layer, and a glass transition point of methyl methacrylate, styrene acrylate, cellulose-based resin alone or a mixture of such resins on the dye-receiving layer is 100 ° C. or higher. It is characterized by having a protective layer mixed with an ultraviolet absorber, and having a glass transition point of 100 ° C or more on the dye receiving layer, methyl methacrylate, styrene acrylate, cellulose resin alone or a mixture of such resins. The absorbance at 360nm wavelength of the coating layer made by mixing UV absorber
The inventors of the present invention have found that the provision of a protective layer having a thickness of 1.5 or more solves the above-mentioned problems of the prior art.

Hereinafter, the present invention will be described in more detail with reference to the drawings. FIG. 1 is a sectional view of the thermal transfer recording image receiving sheet of the present invention. The thermal transfer recording image receiving sheet 5 has a cushion layer 2, a dye receiving layer 3 and a protective layer 4 on a base paper 1. As the base paper used for the base paper 1 of the image receiving sheet for thermal transfer recording of the present invention, known papers such as high quality paper, coated paper, art paper, synthetic paper, cast paper and the like can be used, and 50 to 200 g / m2. A weight of ² is preferred.

In the present invention, the cushion layer 2 formed on the base paper 1 is formed by melt extrusion coating a polyolefin resin such as a polyethylene resin or a polypropylene resin or an ethylene ethyl acrylate resin. The above resin cushion layer is generally 10 ~ 70
It is formed on the base paper in the range of μ. It is known to add inorganic pigments such as calcium carbonate, titanium oxide and silica, a fluorescent whitening agent and an antioxidant to the resin cushion layer, and these additives are also added to the resin cushion layer in the present invention. It is possible to add

In the present invention, the dye receiving layer 3 formed on the cushion layer functions to receive a sublimation dye which is sublimated and transferred from the thermal transfer sheet by heating the thermal head. Therefore, the dye-receiving layer of the present invention contains a resin having excellent dye-dyeing properties. As resins having excellent dye-dyeing properties, polyester, vinyl chloride /
It is preferable to use a terpolymer resin of vinyl acetate / maleic anhydride, and other resins capable of dyeing a sublimation dye such as polyvinyl acetate, styrene acrylate, and ethylene vinyl acetate resin can be used. The thickness of the dye receiving layer is preferably 0.5 to 7 μm. If the thickness of the dye receiving layer is less than 0.5 μm, the density of the recorded image will decrease. Also,
When the thickness exceeds 7 μm, the image gloss is lowered due to the reduction in the dyeing density of the dye.

In the present invention, other components used in the dye-receiving layer 3 include inorganic pigments such as calcium carbonate, titanium oxide and silica, and polystyrene for the purpose of improving the whiteness of the dye-receiving layer and the contrast of the image. And organic pigments such as polyethylene, urea / formalin resin, and methylcellulose. In the present invention, the protective layer 4 on the dye-receiving layer improves the fixing property of the sublimation dye of the recorded image, is inferior in dye-dyeing property of the sublimation dye migrating from the thermal transfer sheet, and has excellent dye permeability. A coating layer having excellent water resistance and oil resistance, preventing fading of a recorded image due to natural light, and maintaining durability (surface strength) enough to withstand abrasion and scratching of the recorded image.

In the present invention, the resin used in the protective layer may be a methyl methacrylate, styrene acrylate, or cellulose resin having a glass transition point of 100 ° C. or more, or a mixture of such resins with an ultraviolet absorber. Use A coating liquid obtained by mixing a known ultraviolet absorber (for example, a triazole-based resin) with the above resin mixture for the purpose of preventing fading of a recorded image due to natural light has a thickness of 1 μm.
It is necessary to form the layer so that the absorbance at a wavelength of 360 nm is 1.5 or more. If the absorbance of the protective layer is less than 1.5, image fading of the recorded image due to natural light is extremely undesirable.

The protective layer 4 of the image receiving sheet 5 for thermal transfer recording according to the present invention is in close contact with the surface of the colorant layer of the thermal transfer sheet, and the sublimation dye is transferred from the back side of the thermal transfer sheet by heating the thermal head to perform image recording. Non-reactive methylstyryl modified silicone oil or acrylic / silicone graft polymer, polyurethane / silicone graft polymer, to prevent fusion between the protective layer and the colorant layer.
Various additives such as a self-crosslinking type silicone modified acrylic resin, fluorine powder, silicone powder and the like can be added and used. In addition, inorganic pigments such as calcium carbonate, titanium oxide, and silica, and organic pigments such as polystyrene, polyethylene, urea-formalin resin, and methylcellulose can be used to adjust the glossiness of the recorded image.

In the present invention, the method of applying the coating of the dye receiving layer 3 and the protective layer 4 on the cushion layer 2 includes coating such as Meyer bar coating, gravure coating, air knife coating, and roll coating. It can be formed by applying and drying by a method.

[0012]

Next, the present invention will be described in more detail with reference to Examples, but it should not be construed that the invention is limited thereto.
In addition, the part in an Example shows a solid content weight ratio.

Examples 1 to 3 Coated paper (product name: NP, manufactured by Nippon Paper Industries Co., Ltd.) was used as the base paper.
i Super Art 127.9 g / m ² ) is subjected to corona discharge treatment on one side to produce high density polyethylene (Mitsui Nisseki Polymer)
Extrusion coating was performed at a resin temperature of 310 ° C. (Vicat softening point: 120 ° C., manufactured by Co., Ltd.) to form a 30 μm thick cushion layer. Next, a dye receiving layer paint having the following composition was applied on the obtained cushion layer so as to have a solid content of 5 μm and dried to form a dye receiving layer.

Coating composition Ingredients Compounding amount Polyester resin (trade name: Elitel UE3320, manufactured by Unitika Ltd.) 20 parts Crosslinking agent (trade name: Takenate D110N, manufactured by Takeda Pharmaceutical Co., Ltd.) 3 parts Inorganic pigment (trade name: FA55W, Furukawa 2 parts Toluene 40 parts Ethyl acetate 20 parts Methyl ethyl ketone 15 parts

Further, a protective layer paint having the following composition was applied on the obtained dye-receiving layer so that the solid content was 2 μm, and dried to form a protective layer.

Coating composition Component Blending amount 18 parts of cellulose resin (trade name: CAP482-0.5, glass transition point: 153 ° C., manufactured by Eastman Chemical Co., Ltd.) UV absorber (trade name: Tinuvin 109, manufactured by Ciba Geigy Co., Ltd.) 5 parts Silicone resin (trade name KF410, manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part Organic pigment (trade name: Eposter S, manufactured by Nippon Shokubai Chemical Co., Ltd.) 1 part Toluene 40 parts Ethyl acetate 20 parts Methyl ethyl ketone 15 parts

In order to measure the absorbance of the protective layer, the above paint was applied on a transparent polyester film 50 μm in Example 1.
Coating and drying were performed under the same conditions as in Example 1 to obtain a sample for measuring absorbance. In the above coating composition for the protective layer, a styrene acrylate resin (trade name Lurex A11, glass transition point 128 ° C, Dainippon Ink Chemical Co., Ltd.)
Example 2 was used. In addition, as an ultraviolet absorber, a product using trade name Ubinal D-50 (manufactured by BASF Corporation) instead of trade name Tinuvin 109 was used in Example 3.
And

A test pattern was printed on each of the thermal transfer recording image-receiving sheets obtained above using a sublimation type thermal transfer printer to obtain a recorded image for evaluation. The ink sheet is a commercially available product name of BC-P24 manufactured by Victor Company of Japan, Ltd.
Using 1SJ, the thermal transfer printer is a commercially available TRUE PRINT2200 (trade name, manufactured by Victor Company of Japan, Ltd.) (resolution 30).
0DPI, recording speed 7 mm / sec).

Comparative Example 1 A protective layer was formed in the same manner as in Example 1 except that a polyester resin having a glass transition point of 95 ° C. (trade name: Elitel UE3690, manufactured by Unitika Ltd.) was used as the resin for the protective layer.

Comparative Example 2 A protective layer was formed in the same manner as in Example 1 except that the blending amount of Tinuvin 109 (trade name) as an ultraviolet absorber for the protective layer was changed to 2 parts.

Comparative Example 3 The protective layer on the dye receiving layer was removed, and the coating composition of the dye receiving layer was changed to a silicone resin (trade name KF410, manufactured by Shin-Etsu Chemical Co., Ltd.).
The dye receiving layer was formed in the same manner as in Example 1 except that the amount of the dye was 1 part.

Next, for each of the thermal transfer recording image-receiving sheets, the absorbance of each thermal transfer recording image-receiving sheet, the fusion during image recording and the image density, glossiness, fixability, and image fading of the recorded image are determined by the following methods. , Durability and the like were evaluated.

(1) Absorbance of Thermal Transfer Recording Image-Receiving Sheet The absorbance of the protective layer at 360 nm was measured using a spectrophotometer type 320 manufactured by Hitachi, Ltd. and indicated. (2) Fusing at the time of thermal transfer recording The fusing between the color material layer surface of the thermal transfer sheet and the protective layer surface of each image receiving sheet for thermal transfer recording at the time of thermal transfer recording depends on the presence or absence of peeling noise during image recording. evaluated. (3) Image Density of Recorded Image A magenta reflection density was measured using a Macbeth RD-918 reflection densitometer manufactured by Macbeth Corporation.

(4) Glossiness of Recorded Image The glossiness of the image was measured by using a gloss checker IG-310 (trade name, manufactured by Horiba, Ltd.) and measuring the magenta image glossiness at an irradiation angle of 60 degrees. . (5) Fixing property of the image Keep eraser manufactured by Hoshia Co., Ltd. at 20 ° C on the recorded image.
The sample was placed under an environment of 65% RH for 8 hours, and the difference in image density (A) of magenta color before and after the processing was indicated. Further, the magenta image density difference (B) before and after the processing of the recorded image was stored for 7 days in an environment of 30 ° C. and 80% RH. (Image density measurement: Trade name Macbeth RD918 reflection densitometer)

(6) Fading of image The recorded image was irradiated for 24 hours using an ultraviolet long life fade meter (trade name: FAL-3, manufactured by Suga Test Instruments Co., Ltd.). The magenta color image density difference before and after irradiation is shown. (Image density measurement: Macbeth RD918 type reflection densitometer) (7) Durability of image The surface strength of the protective layer of the recorded image is a Haydon-14 type surface quality tester manufactured by Shinto Kagaku Co., Ltd. A scratch test was performed with pencils having different hardnesses. The pencil hardness at which the scratches began to enter was noted. Table 1 shows the evaluation results of the thermal transfer recording image-receiving sheets. * In addition, the column of image glossiness in the table
The higher the numerical value, the better the evaluation result. The lower the value, the better the evaluation result.

[0026]

[Table 1] ：: Each performance item is within the target range, indicating a good evaluation result. ×: Indicates that the performance in a plurality of performance items does not reach the target.

As is clear from Table 1, the glass transition point is 10
A thermal transfer recording image-receiving sheet having a protective layer formed so that the absorbance of a dried coating film becomes 1.5 or more using a resin mixture of a resin at 0 ° C. or higher and an ultraviolet absorber is excellent in fixability and durability. At the same time, an image receiving sheet for thermal transfer recording with less fading of the image due to aging was obtained. Further, in the comparative examples, the image glossiness or the fixability / fading property
One or more of the durability properties of the image receiving sheet for thermal transfer recording were out of the target range of the present invention.

[0028]

The image-receiving sheet for thermal transfer recording according to the present invention is a composite comprising a plurality of layers in which a cushion layer, a dye-receiving layer and a protective layer are formed on a base paper. Since the protective layer is not formed on the outermost layer and does not directly come into contact with an object and is excellent in water resistance and oil resistance, it has excellent fixability of a sublimation dye of a recorded image. Further, since the protective layer is excellent in ultraviolet absorption and surface strength aptitude, it has excellent characteristics such as storage stability of the recorded image over time and durability.

[Brief description of the drawings]

FIG. 1 is a cross-sectional configuration diagram of an image receiving sheet for thermal transfer recording of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base paper 2 Cushion layer 3 Dye receiving layer 4 Protective layer 5 Image receiving sheet for thermal transfer recording

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-238791 (JP, A) JP-A-62-240588 (JP, A) JP-A-61-144394 (JP, A) 64989 (JP, A) JP-A 1-257095 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41M 5/38-5/40

Claims (2)

(57) [Claims] 1. A thermal transfer recording image receiving sheet having a dye receiving layer for receiving a sublimation dye transferred from a thermal transfer sheet by heating on a base paper, wherein a cushion layer is provided between the base paper and the dye receiving layer. On the dye-receiving layer, a resin having a glass transition point of 100 ° C. or higher is mixed with an ultraviolet absorber, and has an absorbance of 1.5 at a wavelength of 360 nm.
An image-receiving sheet for thermal transfer recording, comprising the protective layer described above. 2. The image receiving device for thermal transfer recording according to claim 1, wherein the protective layer contains methyl methacrylate, styrene acrylate, or a cellulose resin having a glass transition point of 100 ° C. or higher, alone or a mixture thereof. Sheet.