JPH0976649A - Thermal transfer type recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal transfer type recording material having excellent surface smoothness on the surface, high image density and image glossiness of a recorded image, excellent gradation reproducibility and always a stable color and color tone. SOLUTION: The thermal transfer type recording material has a dye receptive layer 2 for receiving sublimable dye to be transferred from a heat transfer sheet by heating on a base sheet, and comprises the heat transfer sheet so formed that the softening point of the dried coating films of the dye receptive layer 2 and a synthetic resin layer 3 made by mixing a colloidal silica composite acrylic emulsion having resin solid ratio of 30 to 70% on a release sheet 1 and the dye receptive layer 2 having surface smoothness of 10,000sec or more formed by integrating the transfer sheet with base sheet 6 by a dry laminating method and then releasing to remove the sheet 1.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to sublimation transfer of a heat sublimation dye in a color material layer from a color material sheet provided with a color material layer containing a heat sublimation dye by heating with a thermal head or the like. The present invention relates to a thermal transfer type recording material capable of obtaining a recorded image.

[0002]

Sublimation type thermal transfer using a thermal transfer sheet having a color material layer containing a thermal sublimation type dye and a thermal transfer type recording material which receives the sublimation dye transferred from the back surface of the thermal transfer sheet by heating of a thermal head. The recording method has been attracting attention as a method of providing a color hard copy that is similar to a color photograph with excellent gradation reproducibility.

Conventionally, as a thermal transfer type recording material, a coating solution in which finely powdered silica, calcium carbonate and the like are mixed and dispersed with a binder such as a thermoplastic butyral resin is applied and dried on a base material such as high quality paper. To form a dye receiving layer.
However, when a dye-receiving layer is formed on a substrate with low surface smoothness, such as high-quality paper, it is possible to obtain a recorded image with excellent gradation reproducibility due to missing transfer, especially in highlight areas. I can't. In particular, in an image with many highlight portions, the transfer omission was a fatal defect. Further, the thermal transfer type recording material using a substrate having low surface smoothness has poor adhesion when image recording is performed by superimposing the color material layer surface of the coloring material sheet and the dye receiving layer surface of the thermal transfer recording material. However, dyeing of the sublimation dye to the dye receiving layer is difficult to occur, and there is a problem that a recorded image with high glossiness and high image density cannot be obtained.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the problems of gradation reproducibility of recorded images, image density characteristics, image glossiness, and the like, and is excellent in surface smoothness of a thermal transfer recording material. It is an object of the present invention to provide a thermal transfer type recording material whose recorded image always shows stable color and tone values.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have produced a laminate having a dye-receiving layer formed on the release layer of a release sheet, A synthetic resin prepared by blending a colloidal silica composite acrylic emulsion having a resin solid content ratio of 30 to 70% was formed on the dye receiving layer of the laminate so that the softening point of the dry coating film was 45 to 80 ° C. A transfer sheet is prepared, the synthetic resin layer surface and the base paper are integrated by an adhesive layer by a dry lamination method, and then the release sheet is peeled and removed so that the surface smoothness is Oken high smoothness. The present invention was found to solve the above-mentioned problems by featuring a dye receiving layer having a densitometer of 10,000 seconds or more.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in more detail with reference to the drawings. FIG. 1 is a cross-sectional configuration diagram of a transfer sheet of the present invention, in which a transfer sheet 4 has a dye receiving layer 2 and a synthetic resin layer 3 on a release sheet 1. The release sheet of the present invention has a release layer formed on a plastic sheet support. Examples of the plastic sheet support include polyethylene, polypropylene, polyethylene terephthalate, triacetate, polycarbonate, and other plastic sheets. In particular, biaxially stretched polyethylene terephthalate is preferable because it is excellent in strength, heat resistance, dimensional stability and the like. The thickness of the plastic sheet support is not particularly limited,
12 to 150 μm is suitable. Moreover, the resin for the release layer formed on the plastic sheet support should be selected in consideration of the adhesiveness with the plastic sheet support, the release property with the dye receiving layer, the coating suitability, and the like. It is preferable to use a release agent formed by thermally crosslinking an acrylic / stearic acid copolymer and an organic acid. The thickness of the release layer formed on the plastic sheet support is preferably 0.1 to 7.0 μm, and particularly preferably 0.5 to 5.0 μm.

The release layer of the present invention has a particle size of 0.
Inorganic pigments of 01-5 μm silicon dioxide, calcium carbonate, alumina, etc., and plastic powders such as polyethylene, polypropylene, polyethylene terephthalate, polystyrene, polycarbonate, ethyl acrylate resin, methacrylic acid resin, and fine powder of starch, cellulose, etc. Can also be used for matting (roughening), and the degree of matting can be controlled by the type of matting agent, the particle size and the amount added.

In the present invention, the dye receiving layer 2 formed on the release sheet 1 functions to receive the sublimation dye transferred from the thermal transfer sheet by heating the thermal head. The dye-receiving layer of the present invention contains a resin having excellent dye-dyeability. As the resin having excellent dye-dyeability, it is preferable to use polyester, vinyl chloride / vinyl acetate / maleic anhydride terpolymer resin,
In addition, a resin capable of dyeing a sublimation dye such as polyvinyl acetate, styrene acrylic, ethylene vinyl acetate copolymer resin can be used. Other components used in the dye receiving layer include inorganic pigments such as calcium carbonate, titanium oxide, and silica, polystyrene, polyethylene, urea / formalin resin, and methyl cellulose for the purpose of improving whiteness and image contrast of the dye receiving layer. It is also possible to use the organic pigments.

In order to prevent fusion of the heat transfer sheet and the heat transfer type recording material during image recording, non-reactive methyl styryl modified silicone oil, acrylic / silicone graft polymer, polyurethane / silicone graft polymer It is also possible to add various additives such as self-crosslinking silicone-modified acrylic resin, fluorine powder and silicone powder.

The dye-receiving layer of the present invention is excellent in surface smoothness of the surface of the dye-receiving layer, has high gradation reproducibility of recorded images, high image density characteristics and image glossiness, and exhibits stable color and tone. Therefore, it is preferable that the release layer is formed so that the surface smoothness is 10,000 seconds or more. Smoothness 10
If the time is less than 000 seconds, the adhesion between the thermal transfer sheet and the thermal transfer recording material during image recording will be insufficient, resulting in a decrease in dye dyeing efficiency and gradation reproducibility and a poor recorded image. Not preferable. The thickness of the dry coating film of the dye receiving layer formed on the release layer is preferably 0.5 to 5.0 μm. Particularly preferably, the formed thickness of the dry coating film is 1.0 to 3.0 μm.
It is.

Next, the synthetic resin layer 3 formed on the dye receiving layer 2 of the present invention has not only the adhesiveness with the dye receiving layer but also the sublimation dye transferred from the thermal transfer sheet by the heating of the thermal head. It is required to increase the image density of the recorded image by stopping on the layer surface and to have heat resistance without causing the synthetic resin layer to be thermally deformed by the heat from the thermal head and not lowering the surface smoothness of the dye receiving layer surface. . Further, appropriate flexibility is also required to enhance the adhesion between the thermal transfer sheet and the thermal transfer recording material for efficiently dyeing the sublimation dye on the dye receiving layer.

The synthetic resin layer in the present invention is a synthetic resin prepared by blending a colloidal silica composite acrylic emulsion having a resin solid content ratio of 30 to 70% and a softening point of a dry coating film of 45.
It is formed so as to have a temperature of ~ 80 ° C. As the synthetic resin used in the synthetic resin layer, it is possible to use colloidal silica composite acrylic emulsion as a main binder and to mix and use other synthetic resin. As the target resin,
Resins such as polyester, styrene-acrylic, polyvinyl alcohol, polyethylene, and acrylic.

The resin solid content ratio of the colloidal silica composite acrylic emulsion forming the synthetic resin layer of the present invention is 30.
If it is less than%, the heat resistance and the heat insulating property are deteriorated, and the surface smoothness of the dye receiving layer is deteriorated due to the thermal deformation of the synthetic resin layer due to the heat of the thermal head at the time of image recording, and the image density and the image glossiness are deteriorated. The recorded image is not preferable. On the other hand, when the resin solid content ratio exceeds 70%, a hard coating film is formed, the flexibility is largely deteriorated, and the adhesiveness between the thermal transfer sheet and the thermal transfer recording material during image recording becomes insufficient, so that the sublimation occurs. The dyeing efficiency of the dye is lowered, and the recorded image is inferior in gradation reproducibility and image density, which is not preferable.

The softening point of the dry coating film of the synthetic resin layer of the present invention is
When the temperature is lower than 45 ° C, the synthetic resin layer is thermally deformed by the heat of the thermal head during image recording, which adversely affects the surface of the dye receiving layer and reduces the surface smoothness, resulting in a recorded image with poor image gloss, which is not preferable. . Further, since the dyeing suitability of the sublimation dye is improved, a recorded image is inferior in image density and image glossiness as the dyeing density of the sublimation dye is reduced, which is not preferable. On the contrary, when the softening point of the dry coating film is higher than 80 ° C., the coating film becomes hard and the flexibility is largely reduced, and the adhesion between the thermal transfer sheet and the thermal transfer recording material during image recording becomes insufficient, The dye sublimation efficiency of the sublimation dye is lowered, resulting in a recorded image with poor gradation reproducibility and image density, which is not preferable.

Further, it is known to add an inorganic pigment such as calcium carbonate, titanium oxide or silica, a fluorescent whitening agent and an antioxidant to the synthetic resin layer. It is possible to add additives such as.
The softening point is Thermomechanical Analyzer, product name T
The softening temperature measured by MA-2940 (manufactured by Dupont) is displayed. Next, FIG. 2 is a cross-sectional structure showing a state in which the synthetic resin layer surface of the transfer sheet 4 and the base paper 6 are integrated by a dry laminating method via the adhesive layer 5, and then the release sheet is peeled and removed. It is a figure. 3 is a cross-sectional configuration diagram of the thermal transfer recording material 7 according to the present invention obtained by peeling and removing the release sheet in FIG.

For the adhesive layer 5 for adhering the transfer sheet and the base paper of the present invention, a known adhesive such as a polyurethane two-component adhesive or an acrylic two-component adhesive may be used. I can. The thickness of the adhesive formed is preferably about 3 to 8 μm. As the base paper 6 used in the present invention, known papers such as coated papers, art papers, synthetic papers and cast papers can be used, and those having a weight of 50 to 200 g / m ² are preferable. Incidentally, in the present invention, as a method for forming the release agent of the release sheet 1 and the paint of the dye receiving layer 2, the synthetic resin layer 3 and the adhesive layer 5, Meyer bar coating, gravure coating, air knife coating, roll It can be formed by coating and drying by a coating method such as coating.

[0017]

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.

Example 1 A release sheet was obtained by applying a coating composition having the following composition to one side of a transparent polyethylene terephthalate film having a thickness of 50 μm and drying it to form a release layer having a thickness of 3 μm. [Release layer formulation] Release agent (Tesfine 322, manufactured by Hitachi Chemical Co., Ltd.) 15 parts Curing agent (paratoluene sulfonic acid, manufactured by Kanto Chemical Co., Inc.) 5 parts Matting agent (trade name) Mizuka Seal SK7 (particle size 1.5 μm, manufactured by Mizusawa Chemical Co., Ltd.) 5 parts Toluene 25 parts Ethyl acetate 25 parts Methyl ethyl ketone 25 parts

Next, a coating composition having the following composition was applied onto the release layer and dried to obtain a dye receiving layer having a thickness of 2 μm. [Dye Receptive Layer Formulation] Polyester resin (Brand name Elitel UE3320, manufactured by Unitika Ltd. 15 parts) Titanium oxide (Brand name FA55W, manufactured by Furukawa Kikai Metal Co., Ltd.) 5 parts Anti-fusing agent (Brand name SA45, Teikoku Kagaku) 1 part Antistatic agent (trade name: Eleek PS-909, Yoshimura Yushi Kagaku Co., Ltd.) 2 parts Toluene 25 parts Ethyl acetate 25 parts Methyl ethyl ketone 20 parts Dimethylformamide 7 parts

Next, a colloidal silica composite acrylic emulsion (trade name: Movinyl 803) was formed on the dye receiving layer.
0, Hoechst Synthetic Co., Ltd.) and polyester resin (trade name: Vylonal MD1200, Toyobo Co., Ltd.) with a resin solid content ratio of 30/70 mixed and dried to obtain a softening point of 15 μm. A synthetic resin layer at 80 ° C was formed to obtain a transfer sheet.
Then, using a dry laminator, a polyurethane adhesive coating described below is applied and dried on the synthetic resin layer of the obtained transfer sheet at a speed of 60 m / min and a drying temperature of 80 ° C. to form a thickness of 5 μm, Laminated with coated paper (product name: NPi Super Art 127.9 (g / m ² ), manufactured by Nippon Paper Industries Co., Ltd.) at a laminating pressure of 5 kg / cm ² and laminated to remove the release sheet. A thermal transfer recording material having a layer surface smoothness of 11500 seconds by a Oken high-level smoothness meter was obtained.

[Formulation for Adhesive Layer] Polyurethane resin (manufactured by Toyo Morton Co., Ltd., trade name Adcote 577-1) 15 parts Curing agent (manufactured by Toyo Morton Co., Ltd., trade name CAT-10L) 5 parts Toluene 40 parts 40 parts of ethyl acetate The thermal transfer recording material obtained above was printed with a test pattern using a sublimation thermal transfer printer to obtain a recorded image for evaluation. The ink sheet used was a commercial product name BC-P241SJ manufactured by Nippon Victor Company Limited, and the thermal transfer printer was a commercial product name T manufactured by Nippon Victor Company Limited.
RUE PRINT2200 (resolution 300 DPI, recording speed 7 mm / sec) was used.

Example 2 As the coating material for the synthetic resin layer, the polyester resin used in Example 1 was used, and the same kind of trade name Vylonal MD1100 (Toyobo Co., Ltd.) was used.
(Manufactured by K.K. Co., Ltd.) and a dry coating film having a softening point of 45 ° C. was used as a synthetic resin layer. A transfer type recording material was prepared.

Example 3 As the coating material for the synthetic resin layer, the polyester resin used in Example 1 was used as an acrylic resin (trade name Primal HA-8,
(Made by Japan Acrylic Co., Ltd.) and changed the resin mixing ratio.
Transfer type with a smoothness of 11000 seconds by the Oken type high smoothness meter on the dye receiving layer surface in the same manner as in Example 1 except that the synthetic resin layer was changed to 70/30 and the softening point of the dry coating film was 70 ° C. A recording material was prepared.

Comparative Example 1 A synthetic resin layer coating material was prepared in the same manner as in Example 1 except that the solid content ratio of the resin in Example 1 was 25/75 and the dry coating film had a softening point of 70 ° C. A thermal transfer recording material having a smoothness of 12000 seconds on a dye-receiving layer surface by a Oken type high smoothness meter was prepared.

Comparative Example 2 The same procedure as in Example 3 was repeated except that the solid content ratio of the resin of Example 3 was 75/25 and the dry coating had a softening point of 78 ° C. as the synthetic resin layer coating material. As a result, a thermal transfer recording material having a smoothness of 8500 seconds on the surface of the dye receiving layer by the Oken type high smoothness meter was prepared.

Comparative Example 3 As the coating material for the synthetic resin layer, the polyester resin used in Example 1 was used as the same kind of trade name Bayronal MD1400 (Toyobo Co., Ltd.).
(Manufactured by K.K. Co., Ltd.) and a dry coating film having a softening point of 40 ° C. was used as a synthetic resin layer. A thermal transfer recording material was prepared.

Comparative Example 4 As a coating material for a synthetic resin layer, the polyester resin used in Example 1 was used as a polyvinyl alcohol resin (trade name: PVA11).
7, manufactured by Kuraray Co., Ltd.) and a synthetic resin layer having a dry coating film softening point of 83 ° C. was used. A thermal transfer recording material of 9000 seconds was prepared.

Comparative Example 5 As the coating material for the releasing layer, the dye receiving layer surface was coated in the same manner as in Example 1 except that the matting agent used in Example 1 was changed and 5 parts of silica having a particle size of 3.5 μm was added. A thermal transfer type recording material having a smoothness of 6500 seconds using a Ken type high smoothness meter was prepared. [Release layer formulation] Release agent (Hitachi Chemical Polymer Co., Ltd., trade name Tesfine 322) 25 parts Curing agent (Kanto Chemical Co., Inc., paratoluene sulfonic acid) 5 parts Matting agent (Fuji Silysia Chemicals Co., Ltd., trade name Sylysia 445 (particle size 3.5 μm)) 5 parts Toluene 25 parts Ethyl acetate 25 parts Methyl ethyl ketone 15 parts

Next, regarding each thermal transfer recording material,
The following methods were used to evaluate the smoothness, glossiness, image density, gradation reproducibility, storability, presence or absence of fusion, etc. of each thermal transfer recording material. (1) Smoothness The smoothness of the surface of the dye receiving layer was measured with a Oken type high smoothness meter. (2) Glossiness The glossiness of the recorded image was measured by using a gloss checker IG-310 manufactured by Horiba, Ltd. under a magenta color at an irradiation angle of 60 degrees. (3) Image density The image density of the recorded image is Macbeth RD manufactured by Macbeth Co., Ltd.
The reflection density of magenta color was measured using a -918 type reflection densitometer.

(4) Gradation reproducibility The recorded image is visually confirmed, and a portion where no transfer omission occurs is D
It is expressed in OT%. The target value is 10% DOT reproduction. (5) Storability of recorded image The recorded image was stored for 30 days in an environment of 20 ° C. and 65% RH. The difference in magenta image density before and after storage is shown. The image density difference target value is 0.10. (Image density measurement: Macbeth RD918 type reflection densitometer) (6) Presence / absence of fusing during thermal transfer recording Fusing between the color material layer surface of the thermal transfer sheet and the dye receiving layer surface of each thermal transfer recording image receiving sheet during image recording In regard to, the evaluation was made based on whether or not peeling noise was generated. Tables 1 and 2 show the results of performance evaluation of the thermal transfer recording image-receiving sheets.

[0031]

[Table 1]

[0032]

[Table 2]

* In the table, smoothness, image density, and image glossiness indicate a better evaluation result as the indicated numerical values increase, and gradation reproducibility and storability indicate a better evaluation result as the indicated numerical values decrease. . * In the column of comprehensive evaluation in the table, a good evaluation result is indicated by ○ in the target range, and △ and × indicate that the performance in one or a plurality of performance items does not reach the target.

As is apparent from Table 2, a synthetic resin layer prepared by blending a colloidal silica composite acrylic emulsion having a resin solid content ratio of 30 to 70% as a synthetic resin layer has a softening point of 45 to 80 ° C. in the dry coating film. The thermal transfer type recording material having the Oken type high smoothness of the dye receiving layer surface of 10,000 seconds or more is excellent in surface smoothness of the thermal transfer type recording material which is the main object of the present invention. With the gradation reproducibility of the recorded image,
It was possible to obtain a thermal transfer recording material having excellent color density and color tone, which was excellent in image density characteristics and image glossiness. Further, in any of the comparative examples, any of the image glossiness of the recorded image, the image density, the gradation reproducibility and the like, or a plurality of performances were thermal transfer type recording materials out of the target range of the present invention.

[0035]

The thermal transfer recording material of the present invention is a transfer sheet in which a dye-receiving layer and a synthetic resin layer having a limited softening point and a compounding ratio of a specific resin are formed on the release layer of a release sheet. It can be prepared by forming a sheet, forming an integrated product of the synthetic resin layer surface of the transfer sheet and the base paper via an adhesive layer by a dry lamination method, and then peeling and removing the release sheet. . The thermal transfer recording material according to the present invention is, of course, excellent in the surface smoothness of the dye receiving layer, but the gradation reproducibility of the recorded image, the image density characteristic and the image gloss, which have been problems of the conventional products. It has excellent characteristics such as solving the problems such as the degree and the like, and the recorded image always shows stable color / tone value.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of the structure of a transfer sheet.

FIG. 2 is a cross-sectional configuration diagram showing a state in which a release sheet is peeled and removed after a synthetic resin layer surface of a transfer sheet 4 and a base paper are integrated by a dry laminating method via an adhesive layer.

FIG. 3 is a cross-sectional configuration diagram of a thermal transfer type recording material of the present invention.

[Explanation of symbols]

 1 Release Sheet 2 Dye Receiving Layer 3 Synthetic Resin Layer 4 Transfer Sheet 5 Adhesive Layer 6 Base Paper 7 Thermal Transfer Recording Material

Claims (1)

[Claims] 1. A thermal transfer recording material having a dye receiving layer for receiving a sublimation dye transferred from a thermal transfer sheet by heating on a base paper, wherein the dye receiving layer is formed on the release layer of the release sheet. And a synthetic resin obtained by blending a colloidal silica composite acrylic emulsion having a resin solid content ratio of 30 to 70% on the dye receiving layer of the laminate, and the softening point of the dry coating film is 45 to 80. After making a transfer sheet formed so that the temperature becomes ° C, the synthetic resin layer surface and the base paper are integrated by an adhesive layer by a dry laminating method, and then the release sheet is peeled and removed to smooth the surface. A thermal transfer recording material characterized by having a dye-receiving layer with a high smoothness meter of Oken type for 10,000 seconds or more.