JP2020059158A - Thermal transfer image receiving sheet - Google Patents

Abstract

To provide a low cost thermal transfer image receiving sheet having stiffness, good in image uniformity, and capable of suppressing phenomenon that a dye penetrates to a back surface even during storage after transfer with less layer structure.SOLUTION: There is provided a thermal transfer image receiving sheet having an image receiving layer 400 on one surface of a paper substrate 100. It is configured that the image receiving layer 400 is outermost surface. Tabor rigidity (JIS-P8125:2000) of the thermal transfer image receiving sheet is 1.47 to 2.94 mN m. Maximum valley depth (ISO4287-1997) of a waviness curve of a surface of the image receiving layer 400 is less than 1.3 μm. A smooth layer 200 has optical reflection concentration of 0.1 or less when thermally transferred at 300 dpi, speed of 10 msec/line and energy of 0.5 mJ/dot.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image receiving sheet used in a thermal transfer type printer.

In general, the heat-sensitive transfer system sublimates (sublimation transfer system) or melts (melt transfer system) the ink in the ink receiving layer of a transfer body called a thermal ribbon by the heat generated in the thermal head of the printer, and then the image receiving sheet side. Is to be transferred to.
At present, the sublimation transfer method among the thermal transfer methods is capable of easily forming full-color images of various images together with the high performance of the printer. Further, the sublimation transfer method is capable of forming an image in a shorter time as compared with silver halide photography, and the equipment is compact. For this reason, thermal transfer image-receiving sheets for sublimation transfer systems are being replaced from silver halide photographs, and are used for self-printing of digital cameras, certificate photographs, and amusement in the corners of convenience stores, consumer electronics mass retailers, and photo shops. Is widely deployed as.

As described above, a thermal transfer image-receiving sheet for a photograph intended to replace a silver halide photograph is required to have a texture close to that of a silver halide photograph. For this reason, resin coated paper (RC paper), which has been used for silver salt photography and is polyamidized paper, is used as a substrate for the thermal transfer image-receiving sheet.
In addition, in order to efficiently use the energy of the thermal head for thermal transfer on the principle of thermal transfer, a porous film is usually disposed as a heat insulating layer under the image receiving layer.
Patent Document 1 describes that a film is attached on the side opposite to the porous film in order to balance the curl due to heat shrinkage during the attachment of the porous film.

However, as described above, when a general thermal transfer image receiving sheet has a multi-layered structure, there is a problem that material cost and production cost increase.
Further, as a result of our study, it has been found that even in the above-mentioned structure, strike-through of the dye occurs depending on the storage environment after transfer. As a countermeasure against this, a layered structure as disclosed in Patent Document 2 has been proposed, but development of a thermal transfer image-receiving sheet capable of preventing strike-through of dye after printing and improving image storability is still desired.

JP, 2005-225092, A Japanese Patent Publication No. 2006-527675

  The present invention has been made by paying attention to the above-mentioned points, has a good elasticity, good image uniformity, and suppresses the phenomenon that the dye escapes to the back side even after storage after transfer, with a small layer configuration. An object is to provide a feasible low-cost thermal transfer image-receiving sheet.

  In order to solve the problems, one embodiment of the present invention is a thermal transfer image-receiving sheet having an image-receiving layer on at least one surface side of a paper substrate, wherein the surface of the image-receiving layer constitutes the outermost surface, and the thermal transfer image-receiving The Taber stiffness of the sheet (JIS-P8125: 2000) is 1.47 mN · m or more and 2.94 mN · m or less, and the maximum valley depth Wv (ISO4287-1997) of the waviness curve of the surface of the image receiving layer is 1.3 μm. Further, it has at least a porous layer and a smooth layer between the paper base material and the image receiving layer, and the smooth layer has a speed of 300 dpi, a speed of 10 msec / line, and a speed of 0.5 mJ / dot. The summary is that the optical reflection density of the surface of the smooth layer is 0.1 or less when the transfer body is thermally transferred with the energy of 1.

  According to the thermal transfer image-receiving sheet of the aspect of the present invention, the image uniformity is good while maintaining the elasticity, and it becomes possible to prevent the dye from leaking to the back surface even after storage after transfer.

It is a sectional view showing an example of a schematic structure of a thermal transfer image receiving sheet concerning an embodiment based on the present invention. It is a figure explaining the maximum valley depth (Wv).

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Overall structure of image receiving sheet)
As shown in FIG. 1, the thermal transfer image receiving sheet of the present embodiment has an image receiving layer 400 on one surface side (upper surface side) of the paper base material 100. A smooth layer 200 and a porous layer 300 are provided between the paper base 100 and the image receiving layer 400. The smooth layer 200 and the porous layer 300 may not be provided.

(Paper substrate 100)
The paper base material 100 is required to have heat resistance and strength that are not softened and deformed by the heat and pressure during thermal transfer.
Therefore, as the material of the paper base material 100, for example, condenser paper, glassine paper, sulfuric acid paper, or paper with a high degree of size, synthetic paper (polyolefin-based, polystyrene-based), high-quality paper, art paper, coated paper, resin Examples thereof include coated paper, cast coated paper, wallpaper, backing paper, synthetic resin or emulsion-impregnated paper, synthetic rubber latex-impregnated paper, synthetic resin internal-addition paper, paperboard, and cellulose fiber paper. From the viewpoint of material cost, it is desirable to use high-quality paper, coated paper, or the like as the material of the paper base material 100.
The thickness of the paper base material 100 (the length in the vertical direction in FIG. 1) is appropriately changed according to the strength and heat resistance required for the thermal transfer image-receiving sheet and the material used as the paper base material 100. It is possible. Specifically, the thickness of the paper substrate 100 is preferably in the range of 50 μm or more and 1000 μm or less, and more preferably in the range of 100 μm or less and 300 μm or less.

(Structure of smoothing layer 200)
The smooth layer 200 provides the smoothness of the surface of the base material 100 (achieves the maximum waviness valley depth Wv of 1.3 μm or less) and imparts the rigidity of the thermal transfer image-receiving sheet which is insufficient only with the paper base material 100. There is a function to do.
Further, the smoothing layer 200 has a function of preventing the dye received by the image receiving layer 400 by transfer from being transferred to the paper base material 100.
Therefore, examples of the material of the smooth layer 200 include low-density polyethylene resin, high-density polyethylene resin, acrylic resin, polypropylene resin, polycarbonate resin, urethane resin, vinyl chloride resin, ethylene / vinyl acetate copolymer resin, and the like.

Further, the thickness of the smooth layer 200 can be appropriately changed depending on the smoothness of the paper base material. The thickness of the smooth layer 200 is 10 μm or more and less than or equal to the thickness of the paper base 100 because the texture of the paper is lost when the smooth layer 200 is thicker than the thickness of the paper base 100 and the material cost increases. It is desirable to suppress it.
If the material of the smoothing layer 200 is easily dyed, the dye may escape to the side opposite to the image receiving layer 400, and therefore a material that is difficult to dye is preferable. Specifically, the smooth layer 200 has an optical reflection density of 0.1 on the surface of the smooth layer when the transfer member is thermally transferred at a speed of 10 msec / line and an energy of 0.5 mJ / dot using a thermal transfer device of 300 dpi. The following is preferable.

(Porous layer 300)
The porous layer 300 provides a heat insulating property that prevents the heat applied to the image receiving layer applied during image formation by thermal transfer from being lost by the heat transfer to the paper base material 100 and the like.
As the porous layer 300, a conventionally known layer may be used. For example, as the porous layer 300, one composed of hollow particles and a binder resin, one using a foamed film such as foamed polypropylene film or foamed polyethylene terephthalate, and a skin layer provided on one side or both sides of the foamed film. A heat insulating layer using a composite film can be mentioned. However, when the porous layer 300 is composed of a heat insulating layer using a foamed film or the like, it is preferable to use a heat insulating layer using hollow particles in consideration of cost and curl generated in the bonding process with the base material. preferable.

From the viewpoint of print density, the amount of hollow particles added is preferably such that the porosity of the heat insulating layer (porous layer 300) is 20% or more. In addition, the particle size of the hollow particles is preferably 1.0 μm or less in consideration of the influence on the surface roughness.
The porous layer 300 can be arranged on the smooth layer 200 or below (on the side of the paper substrate 100), but as described above, heat is desired to be retained in the image receiving layer 400. It is desirable to form it on the layer 400 side).

(Image receiving layer 400)
The image receiving layer 400 receives the sublimable dye transferred from the thermal transfer ink sheet during image formation by thermal transfer. Then, by holding the received sublimable dye in the image receiving layer 400, an image is formed and maintained on the surface of the image receiving layer 400.
The image receiving layer 400 may further include a binder resin and a silicone release agent. According to a preferred embodiment, the image receiving layer 400 may further contain a surfactant or a film-forming aid according to various purposes.
Examples of the binder resin include a polyolefin resin, a halogenated polymer, a vinyl polymer, a copolymer resin of an olefin and another vinyl monomer, a cellulose resin, a polycarbonate and the like, and a mixed system of these resins.

  Examples of the polyolefin resin include acrylic resin, vinyl chloride resin, polyethylene and polypropylene. Examples of the halogenated polymer include polyvinyl chloride, vinyl chloride / vinyl acetate copolymer (vinyl chloride-based resin), polyvinylidene chloride and the like. Examples of vinyl polymers include polyvinyl acetate / acrylic copolymers and polyacrylic acid esters. Examples of the olefin include polystyrene resin, polyamide resin, ethylene and propylene. Examples of the cellulose-based resin include ionomer and cellulose diacetate. The binder resin is preferably a vinyl chloride resin. The binder resin is more preferably at least one vinyl chloride resin selected from vinyl chloride / vinyl acetate copolymers and vinyl chloride / acrylic copolymers.

As the release agent contained in the image receiving layer 400, for example, various oils such as silicone-based, fluorine-based and phosphoric ester-based oils, surfactants, various fillers such as metal oxides and silica, and waxes can be used. . These may be used alone or in combination of two or more. Above all, it is preferable to use silicone oil.
The thickness of the image receiving layer 400 may be in the range of 0.1 μm or more and 10 μm or less, and more preferably 0.2 μm or more and 8 μm or less. If necessary, the image receiving layer 400 may contain a crosslinking agent, an antioxidant, a fluorescent dye, or a known additive.

The thermal transfer image receiving sheet having the above-mentioned configuration is configured such that the image receiving layer 400 is the outermost surface.
In addition, according to JIS-P8125: 2000, the Taber rigidity in the direction perpendicular to the printing direction of the thermal transfer image receiving sheet is 1.47 mN · m or more and 2.94 mN · m or less.
In addition, the maximum valley depth Wv of the waviness curve on the surface of the image receiving layer 400 is less than 1.3 μm in the measurement based on ISO4287-1997.

[Maximum valley depth (Wv)]
The maximum valley depth (Wv) is represented by the depth of the deepest valley in the waviness curve at a measurement length (reference length) of 10 mm and a cutoff value (0.8 to 8 mm) as shown in FIG. (ISO4287-1997).
In the present embodiment, 30 or more of the above measurements are measured, and the maximum value is defined as the maximum waviness curve valley depth.

[Optical reflection density]
The optical reflection density was measured by using an ink ribbon used for printing, transfer conditions: 300 dpi, a speed of 10 msec / line, an energy of 0.5 mJ / dot, and a dye thermal transfer to a transfer body, followed by Xrite528 (Xrite). (Manufactured by the same company), the optical reflection density on the surface of the transferred material is measured.

[Taber stiffness]
For the Taber rigidity, a Taber rigidity tester (manufactured by Toyo Seiki Co., Ltd.) was used with a Taber rigidity of a bending angle of 15 degrees in accordance with JIS-P8125: 2000 standard with respect to the direction intersecting at right angles with the printing direction of the image receiving paper. Then, 5 samples were measured 5 times on the left and right sides, and the average value was taken as the Taber stiffness (stiffness).

(Action and others)
According to the thermal transfer image-receiving sheet of the present embodiment, image uniformity is good while maintaining elasticity, and it is possible to prevent the dye from escaping to the back surface even during storage after transfer (see Examples below).

Next, examples based on the present embodiment will be described.
(Preparation of transfer material to be used)
As a base material, a polyethylene terephthalate film having a thickness of 4.5 μm and provided with a single-sided easy adhesion treatment was used. A non-easy-adhesion-treated surface of the base material is coated with a heat resistant slipping layer coating solution having the composition shown below (hereinafter referred to as "heat resistant slipping layer forming coating solution") by a gravure coating method after drying. The heat resistant slipping layer was formed on the base material by coating so that the amount was 0.5 g / m ² and drying at a temperature of 100 ° C. for 1 minute.
A coating solution having the composition shown below (hereinafter referred to as "dye layer coating solution") was applied to the surface of the substrate on which the heat-resistant slipping layer was formed by the gravure coating method so that the coating amount after drying was 0. The dye layer was formed by applying the solution so as to have a concentration of 0.5 g / m ² and drying at a temperature of 90 ° C. for 1 minute to obtain a transfer body. The transfer member obtained here is used for image formation and measurement of the diffusion rate.

[Coating liquid for forming heat resistant slipping layer]
Acetal resin 5.0 parts Mica 0.5 parts Magnesium hydroxide 0.1 parts Phosphate ester 0.9 parts Toluene 5.5 parts MEK 13.0 parts

[Dye layer coating liquid]
C. I. Disperse Red 343 4.5 parts C.I. I. Disperse Violet 26 2.0 parts Polyvinyl acetal resin 5.0 parts Toluene 29.5 parts Methyl ethyl ketone 59.0 parts

(Example 1)
Gloss coated paper (Aurora coated paper, Nippon Paper Industries) having a basis weight of 127.9 g was used as a paper substrate. On one surface of the paper substrate 1, apply a coating solution 1 for a smooth layer having the following composition so that the thickness after drying is 10 μm, and irradiate with UV irradiation amount of 320 mJ / cm × 3 times. The smooth layer of Example 1 was produced according to.

[Smooth layer coating liquid 1]
・ Acrylic resin (KRX-773-19 ADEKA)
In the smoothing layer of Example 1 manufactured as described above, a solid image was transferred at an energy of 300 dpi, 10 msec / line, and 0.5 mJ / dot using a transfer body and a thermal simulator.
The optical reflection density on the surface of the transferred smooth layer of Example 1 was measured by X-rite 528, and it was 0.10.
Further, a porous coating liquid 1 having the following composition was applied onto the formed smooth layer so that the thickness when dried was 20 μm, and the coating was dried to form a porous layer.

[Porous coating liquid 1]
-Styrene butadiene rubber (SBR) 100.00 parts by mass (Nipol LX110, manufactured by Nippon Zeon Co., Ltd.)
・ Pure water 227.00 parts by mass ・ Hollow particles 34.00 parts by mass (Lowpay Ultra E, particle size 0.4 μm, manufactured by Dow Chemical Japan Co., Ltd.)
Further, a thermal transfer image-receiving sheet of Example 1 was formed by coating a coating solution for an image-receiving layer having the following composition on the porous layer as a heat insulating layer so that the film thickness after drying would be 3 μm. Got

[Coating liquid for image receiving layer]
・ Vinyl chloride emulsion 100.00 parts (Vini Blanc 900, manufactured by Nisshin Chemical Industry Co., Ltd., Tg = 70 ° C., solid content = 40%)
-Ethylene glycol diethyl ether 0.25 part-Silicone release agent 0.17 part (dimethyl silicon NP2406, manufactured by Asahi Kasei Wacker Silicon Co., Ltd., solid content = 60%)
Isocyanate-based curing agent (model number: DNW-6000, manufactured by DIC Corporation) 1.29 parts The thermal transfer image-receiving sheet of Example 1 prepared was measured with a contact-type surface roughness meter ET-4000A, and the undulation maximum valley was measured. The depth was 0.8 μm.
The stiffness of the produced thermal transfer image-receiving sheet of Example 1 was 1.47 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Example 2)
The thickness of the smoothing layer of Example 1 was changed to 30 μm to form the smoothing layer of Example 2. Then, using a transfer body and a thermal simulator, a solid image was transferred at an energy of 300 dpi, 10 msec / line, and 0.5 mJ / dot.
The optical reflection density on the surface of the transferred smoothing layer of Example 2 was measured by X-rite 528, and it was 0.09.
A thermal transfer image-receiving sheet of Example 2 was produced in the same manner as in Example 1 except that the thickness of the smoothing layer was changed.
When the thermal transfer image receiving sheet of Example 2 was measured by a contact type surface roughness meter ET-4000A, the maximum waviness valley depth Wv was 0.8 μm.
The stiffness of the produced thermal transfer image-receiving sheet of Example 2 was 2.74 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Example 3)
The same procedure as in Example 1 was carried out except that the paper base material of Example 1 was changed to a matte coated paper base material (OK top coat matte N, manufactured by Oji Paper Co., Ltd.) having a basis weight of 127.9 g. A thermal transfer image-receiving sheet of Example 3 was obtained.
After forming the smooth layer of the thermal transfer image receiving sheet of Example 3, a solid image was transferred at an energy of 300 dpi, 10 msec / line and 0.5 mJ / dot using a transfer body and a thermal simulator. The optical reflection density of the surface of the transferred smooth layer was measured by X-rite 528, and it was 0.09.
Further, when the thermal transfer image receiving sheet of Example 3 was measured with a contact type surface roughness meter ET-4000A, the maximum waviness valley depth was 1.2 μm.
The stiffness of the produced thermal transfer image-receiving sheet of Example 3 was 2.94 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Example 4)
The thickness of the smoothing layer of Example 1 was changed to 30 μm to form the smoothing layer of Example 4. Then, using a transfer body and a thermal simulator, a solid image was transferred at an energy of 300 dpi, 10 msec / line, and 0.5 mJ / dot. The optical reflection density on the surface of the transferred smoothing layer of Example 4 was measured by X-rite 528, and it was 0.09.
Further, a thermal transfer image-receiving sheet of Example 4 was obtained in the same manner as in Example 1 except that the porous layer was changed to a foamed polypropylene film (Econage NW2, manufactured by Mitsui Chemicals Tohcello Co., Ltd.).
When the thermal transfer image receiving sheet of Example 4 was measured with a contact type surface roughness meter ET-4000A, the maximum waviness valley depth was 0.7 μm.
The stiffness of the produced thermal transfer image-receiving sheet of Example 4 was 2.55 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Example 5)
The paper base material of Example 1 was changed to a paper base material of mat-coated paper (OK Top Coat Mat N, manufactured by Oji Paper Co., Ltd.) having a basis weight of 127.9 g, and the porous layer was a foamed polypropylene film (Econage A thermal transfer image-receiving sheet of Example 5 was obtained in the same manner as in Example 1, except that the porous layer was NW2 or Mitsui Chemicals Tohcello Co., Ltd.
After forming the smooth layer of the thermal transfer image-receiving sheet of Example 5, a solid image was transferred at an energy of 300 dpi, 10 msec / line, and 0.5 mJ / dot using a transfer body and a thermal simulator. The optical reflection density of the surface of the transferred smooth layer was measured by X-rite 528, and it was 0.09.
The stiffness of the produced thermal transfer image-receiving sheet of Example 5 was 2.65 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Comparative Example 1)
The same paper substrate 1 as in Example 1 was used, and one surface was coated with a coating solution 2 for a smoothing layer having the following composition so that the thickness after drying was 20 μm to prepare a smoothing layer.

[Smooth layer coating liquid 2]
・ Polyester resin (Vylonal MD1200 Toyobo Co., Ltd.)
In the smooth layer produced as described above, a solid image was transferred at an energy of 300 dpi, 10 msec / line, and 0.5 mJ / dot using a transfer body and a thermal simulator.
The optical reflection density of the transferred smooth layer surface was measured by X-rite 528 and found to be 2.30.
Further, the porous layer and the image receiving layer were the same as in Example 1 to obtain a thermal transfer image receiving sheet of Comparative Example 1.
When the thermal transfer image receiving sheet of Comparative Example 1 was measured with a contact type surface roughness meter ET-4000A, the maximum waviness valley depth was 0.8 μm.
The stiffness of the produced thermal transfer image-receiving sheet of Comparative Example 1 was 0.88 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Comparative Example 2)
The thickness of the smoothing layer of Comparative Example 1 was changed to 30 μm, and the smoothing layer of Comparative Example 2 was formed. Then, using a transfer body and a thermal simulator, a solid image was transferred at an energy of 300 dpi, 10 msec / line, and 0.5 mJ / dot.
The optical reflection density of the surface of the transferred smooth layer was measured by X-rite 528, and it was 0.09.
Further, the thermal transfer image-receiving sheet of Comparative Example 2 was obtained with the same porous layer and image-receiving layer as in Example 1.
When the thermal transfer image-receiving sheet of Comparative Example 2 was measured with a contact type surface roughness meter ET-4000A, the maximum waviness valley depth was 0.7 μm.
The stiffness of the produced thermal transfer image-receiving sheet of Comparative Example 2 was 0.98 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Comparative Example 3)
The same paper base material as in Example 1 was used, and one surface was coated with a coating solution 3 for a smoothing layer having the following composition so that the thickness after drying was 20 μm, and the smoothing layer of Comparative Example 3 was applied. It was made.

[Smooth layer coating liquid 3]
・ Urethane resin (Superflex 210 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
In the smooth layer of Comparative Example 3 produced as described above, a solid image was transferred at an energy of 300 dpi, 10 msec / line, and 0.5 mJ / dot using a transfer body and a thermal simulator.
The optical reflection density on the surface of the transferred smoothing layer of Comparative Example 3 was measured by X-rite 528 and found to be 1.90.
Further, the thermal transfer image-receiving sheet of Comparative Example 3 was obtained with the same porous layer and image-receiving layer as in Example 1.
When the thermal transfer image-receiving sheet of Comparative Example 3 was measured by a contact type surface roughness meter ET-4000A, the maximum waviness valley depth was 0.6 μm.
The stiffness of the produced thermal transfer image-receiving sheet of Comparative Example 3 was 0.88 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Comparative Example 4)
The same paper substrate 1 as in Example 1 was used, and one surface was coated with a coating solution 3 for a smooth layer so that the thickness after drying was 30 μm, to prepare a smooth layer of Comparative Example 4.
In the smooth layer of Comparative Example 4 produced as described above, a solid image was transferred at an energy of 300 dpi, 10 msec / line, and 0.5 mJ / dot using a transfer body and a thermal simulator.
The optical reflection density on the surface of the transferred smoothing layer of Comparative Example 4 was measured by X-rite 528 and found to be 1.90.
Further, the porous layer and the image receiving layer were the same as in Example 1 to obtain a thermal transfer image receiving sheet of Comparative Example 4.
When the thermal transfer image receiving sheet of Comparative Example 4 was measured with a contact type surface roughness meter ET-4000A, the maximum waviness valley depth was 0.6 μm.
The stiffness of the produced thermal transfer image-receiving sheet of Comparative Example 4 was 0.88 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Comparative Example 5)
The thermal transfer image-receiving sheet of Comparative Example 5 was the same as Comparative Example 4 except that the porous layer of Comparative Example 4 was changed to a porous layer of a foamed polypropylene film (Econage NW2, manufactured by Mitsui Chemicals Tohcello Co., Ltd.). Got
After forming the smooth layer of the thermal transfer image-receiving sheet of Comparative Example 5, a transfer body and a thermal simulator were used to transfer a solid image at an energy of 300 dpi, 10 msec / line, and 0.5 mJ / dot. The optical reflection density of the surface of the transferred smooth layer was measured by X-rite 528, and it was 1.90.
When the thermal transfer image-receiving sheet of Comparative Example 5 was measured with a contact type surface roughness meter ET-4000A, the maximum waviness valley depth was 0.6 μm.
The stiffness of the prepared thermal transfer image-receiving sheet of Comparative Example 5 was 0.78 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Comparative Example 6)
The same paper base material as in Example 1 was used, and one surface was coated with a coating solution 4 for a smooth layer having the following composition so that the thickness after drying would be 30 μm to prepare a smooth layer of Comparative Example 6. did.

[Smooth layer coating liquid 4]
・ Styrene butadiene rubber (SBR) (NipolLX110, manufactured by Zeon Corporation)
In the smooth layer of Comparative Example 6 produced as described above, a solid image was transferred at an energy of 300 dpi, 10 msec / line, and 0.5 mJ / dot using a transfer body and a thermal simulator.
The optical reflection density on the surface of the transferred smoothing layer of Comparative Example 6 was measured by X-rite 528 and found to be 1.80.
Further, the thermal transfer image-receiving sheet of Comparative Example 6 was obtained with the same porous layer and image-receiving layer as in Example 1.
When the thermal transfer image receiving sheet of Comparative Example 6 was measured with a contact type surface roughness meter ET-4000A, the maximum waviness valley depth was 1.0 μm.
The stiffness of the produced thermal transfer image-receiving sheet of Comparative Example 6 was 0.88 Nm when measured using a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Comparative Example 7)
The same paper substrate 1 as in Example 1 was used, and one surface was coated with the coating solution 3 for a smooth layer so that the thickness after drying was 30 μm, to prepare a smooth layer for Comparative Example 7.
In the smoothing layer of Comparative Example 7 produced as described above, a solid image was transferred at an energy of 300 dpi, 10 msec / line, and 0.5 mJ / dot using a transfer body and a thermal simulator.
The optical reflection density on the surface of the transferred smoothing layer of Comparative Example 7 was measured by X-rite 528, and it was 1.80.
Further, regarding the porous layer and the image receiving layer, the thermal transfer image receiving sheet of Comparative Example 7 was obtained in the same manner as in Example 1. The thermal transfer image receiving sheet of Comparative Example 7 was measured with a contact type surface roughness meter ET-4000A. However, the maximum undulation valley depth was 0.8 μm.
The stiffness of the produced thermal transfer image-receiving sheet of Comparative Example 7 was 0.88 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Comparative Example 8)
The thermal transfer image of Comparative Example 8 was the same as Comparative Example 4 except that the porous layer of Comparative Example 7 was changed to a porous layer of a foamed polypropylene film (Econage NW2, manufactured by Mitsui Chemicals Tohcello Co., Ltd.). Got the sheet.
After forming the smooth layer of the thermal transfer image-receiving sheet of Comparative Example 8, a solid image was transferred at an energy of 300 dpi, 10 msec / line and 0.5 mJ / dot using a transfer body and a thermal simulator. The optical reflection density of the surface of the transferred smooth layer was measured by X-rite 528 and found to be 1.80.
When the thermal transfer image receiving sheet of Comparative Example 8 was measured with a contact type surface roughness meter ET-4000A, the maximum waviness valley depth was 0.7 μm.
The stiffness of the produced thermal transfer image-receiving sheet of Comparative Example 8 was 0.88 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Comparative Example 9)
The smoothing layer of Example 1 was formed to have a thickness of 5 μm to obtain a smoothing layer of Comparative Example 9.
In the smoothing layer of Comparative Example 9 produced as described above, a solid image was transferred at an energy of 300 dpi, 10 msec / line, and 0.5 mJ / dot using a transfer body and a thermal simulator.
The optical reflection density of the surface of the transferred smoothing layer of Comparative Example 9 was measured by X-rite 528, and it was 0.10.
Further, the thermal transfer image-receiving sheet of Comparative Example 9 was obtained with the same porous layer and image-receiving layer as in Example 1.
When the thermal transfer image receiving sheet of Comparative Example 9 was measured with a contact type surface roughness meter ET-4000A, the maximum waviness valley depth was 1.3 μm.
The stiffness of the produced thermal transfer image-receiving sheet of Comparative Example 9 was 1.27 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Comparative Example 10)
Example 1 The smooth layer was formed to have a thickness of 40 μm to obtain a smooth layer of Comparative Example 10.
In the smooth layer of Comparative Example 10 produced as described above, a solid image was transferred at an energy of 300 dpi, 10 msec / line, and 0.5 mJ / dot using a transfer body and a thermal simulator. The optical reflection density of the surface of the transferred smoothing layer of Comparative Example 10 was measured by X-rite 528, and it was 0.09.
Otherwise, the porous layer and the image receiving layer were the same as in Example 1 to obtain a thermal transfer image receiving sheet of Comparative Example 10.
When the thermal transfer image receiving sheet of Comparative Example 10 was measured with a contact type surface roughness meter ET-4000A, the maximum waviness valley depth was 0.6 μm.
The stiffness of the produced thermal transfer image-receiving sheet of Comparative Example 10 was 3.04 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Comparative Example 11)
The smooth layer of Example 1 was formed to have a thickness of 50 μm to obtain a smooth layer of Comparative Example 11.
In the smooth layer of Comparative Example 11 produced as described above, a solid image was transferred at an energy of 300 dpi, 10 msec / line, and 0.5 mJ / dot using a transfer body and a thermal simulator. The optical reflection density on the surface of the transferred smoothing layer of Comparative Example 11 was measured by X-rite 528, and it was 0.09.
Further, the porous layer and the image receiving layer were the same as in Example 1 to obtain a thermal transfer image receiving sheet of Comparative Example 11.
When the thermal transfer image receiving sheet of Comparative Example 11 was measured with a contact type surface roughness meter ET-4000A, the maximum undulation valley depth was 0.5 μm.
The stiffness of the produced thermal transfer image-receiving sheet of Comparative Example 11 was measured using a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.) to find that the stiffness was 3.23 mN · m.

(Comparative Example 12)
The thermal transfer image-receiving sheet of Comparative Example 12 was the same as that of Example 1, except that the paper base material of Example 1 was changed to a paper base material of high-quality paper (Shiraioi Fine Paper Co., Ltd.) having a basis weight of 127.9 g. Got
After forming the smooth layer of the thermal transfer image-receiving sheet of Comparative Example 12, a solid image was transferred at an energy of 300 dpi, 10 msec / line and 0.5 mJ / dot using a transfer body and a thermal simulator. The optical reflection density of the surface of the transferred smoothing layer of Comparative Example 12 was measured by X-rite 528, and it was 1.30.
Further, the porous layer and the image receiving layer were the same as in Example 1, and a thermal transfer image receiving sheet of Comparative Example 12 was obtained. The thermal transfer image receiving sheet of Comparative Example 12 was measured with a contact type surface roughness meter ET-4000A. As a result, the maximum undulation valley depth was 3.3 μm.
The stiffness of the produced thermal transfer image-receiving sheet of Comparative Example 12 was 1.96 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Comparative Example 13)
Using the same paper substrate as in Comparative Example 12, polyethylene (LC600A Nippon Polyethylene) was melt-extruded on one surface to form a polyethylene resin layer having a thickness of 30 μm as a smooth layer in Comparative Example 13.
In the smooth layer of Comparative Example 13 produced as described above, a solid image was transferred at an energy of 300 dpi, 10 msec / line, and 0.5 mJ / dot using a transfer body and a thermal simulator. The optical reflection density of the transferred smooth layer of Comparative Example 13 measured by X-rite 528 was 1.3.
Other than that, the porous layer and the image receiving layer were the same as in Example 1 to obtain a thermal transfer image receiving sheet of Comparative Example 13.
When the thermal transfer image receiving sheet of Comparative Example 13 was measured by a contact type surface roughness meter ET-4000A, the maximum waviness valley depth was 3.6 μm.
The stiffness of the prepared thermal transfer image-receiving sheet of Comparative Example 13 was 1.18 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Comparative Example 14)
A thermal transfer image-receiving sheet of Comparative Example 14 was obtained in the same manner as Comparative Example 13 except that the thickness of the smoothing layer of Comparative Example 13 was changed to 40 μm.
After forming the smooth layer of the thermal transfer image-receiving sheet of Comparative Example 14, a transfer body and a thermal simulator were used to transfer a solid image at an energy of 300 dpi, 10 msec / line, and 0.5 mJ / dot. The optical reflection density of the surface of the transferred smooth layer was measured by X-rite 528, and it was 1.30.
When the thermal transfer image receiving sheet of Comparative Example 14 was measured by a contact type surface roughness meter ET-4000A, the maximum waviness valley depth was 2.7 μm.
The stiffness of the produced thermal transfer image-receiving sheet of Comparative Example 14 was 1.27 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Comparative Example 15)
A thermal transfer image-receiving sheet of Comparative Example 15 was obtained in the same manner as Comparative Example 13 except that the thickness of the smoothing layer of Comparative Example 13 was changed to 50 μm.
After forming the smooth layer of the thermal transfer image-receiving sheet of Comparative Example 15, a solid image was transferred at an energy of 300 dpi, 10 msec / line, and 0.5 mJ / dot using a transfer body and a thermal simulator. The optical reflection density of the surface of the transferred smooth layer was measured by X-rite 528, and it was 1.30.
When the thermal transfer image-receiving sheet of Comparative Example 15 was measured with a contact type surface roughness meter ET-4000A, the maximum waviness valley depth was 2.0 μm.
The stiffness of the produced thermal transfer image-receiving sheet of Comparative Example 15 was 1.37 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Comparative Example 16)
A thermal transfer image-receiving sheet of Comparative Example 16 was obtained in the same manner as in Comparative Example 13 except that the paper substrate of Comparative Example 13 was changed to the same paper substrate as in Example 5.
After forming the smooth layer of the thermal transfer image-receiving sheet of Comparative Example 16, a solid image was transferred at an energy of 300 dpi, 10 msec / line and 0.5 mJ / dot using a transfer body and a thermal simulator. The optical reflection density of the surface of the transferred smooth layer was measured by X-rite 528, and it was 1.30.
When the thermal transfer image receiving sheet of Comparative Example 16 was measured by a contact type surface roughness meter ET-4000A, the maximum waviness valley depth was 1.3 μm.
The stiffness of the produced thermal transfer image-receiving sheet of Comparative Example 16 was measured using a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.) and the stiffness was 0.98 mN · m.

(Comparative Example 17)
A thermal transfer image-receiving sheet of Comparative Example 17 was obtained in the same manner as in Comparative Example 14 except that the paper substrate of Comparative Example 14 was changed to the same paper substrate as in Example 5.
After forming the smooth layer of the thermal transfer image-receiving sheet of Comparative Example 17, a solid image was transferred at an energy of 300 dpi, 10 msec / line and 0.5 mJ / dot using a transfer body and a thermal simulator. The optical reflection density of the surface of the transferred smooth layer was measured by X-rite 528, and it was 1.30.
When the thermal transfer image receiving sheet of Comparative Example 17 was measured by a contact type surface roughness meter ET-4000A, the maximum waviness valley depth was 1.2 μm.
The stiffness of the produced thermal transfer image-receiving sheet of Comparative Example 17 was 1.08 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Comparative Example 18)
A thermal transfer image-receiving sheet of Comparative Example 18 was obtained in the same manner as in Comparative Example 15 except that the paper substrate of Comparative Example 15 was changed to the same paper substrate as in Example 5.
After forming the smooth layer of the thermal transfer image-receiving sheet of Comparative Example 18, a solid image was transferred at an energy of 300 dpi, 10 msec / line and 0.5 mJ / dot using a transfer body and a thermal simulator. The optical reflection density of the surface of the transferred smooth layer was measured by X-rite 528, and it was 1.30.
When the thermal transfer image receiving sheet of Comparative Example 18 was measured by a contact type surface roughness meter ET-4000A, the maximum waviness valley depth was 1.1 μm.
The stiffness of the prepared thermal transfer image-receiving sheet of Comparative Example 18 was 1.37 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Comparative Example 19)
A polyethylene resin (LC600A Nippon Polyethylene) was melt-extruded between the same paper substrate as in Example 5 and a porous layer of a foamed polypropylene film (Econage NW2, manufactured by Mitsui Chemicals Tohcello Co., Ltd.) for comparison. Nineteen smooth layers were formed and bonded by a sand lam system.
Separately, after forming the smooth layer of the thermal transfer image-receiving sheet of Comparative Example 19, a solid image was transferred at an energy of 300 dpi, 10 msec / line and 0.5 mJ / dot using a transfer body and a thermal simulator. The optical reflection density of the surface of the transferred smooth layer was measured by X-rite 528, and it was 1.30.
After forming the smoothing layer as described above, the image receiving layer was the same as in Example 1 to obtain a thermal transfer image receiving sheet of Comparative Example 19.
When the thermal transfer image receiving sheet of Comparative Example 19 was measured with a contact type surface roughness meter ET-4000A, the maximum waviness valley depth was 1.0 μm.
The stiffness of the produced thermal transfer image-receiving sheet of Comparative Example 19 was 1.27 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Comparative Example 20)
A thermal transfer image-receiving sheet of Comparative Example 20 was obtained in the same manner as in Example 16 except that the same paper base material as in Example 1 was used.
Separately, after forming a smooth layer of the thermal transfer image-receiving sheet of Comparative Example 20, a transfer body and a thermal simulator were used to transfer a solid image with energy of 300 dpi, 10 msec / line, and 0.5 mJ / dot. The optical reflection density of the surface of the transferred smooth layer was measured by X-rite 528, and it was 1.30.
When the thermal transfer image receiving sheet of Comparative Example 20 was measured by a contact type surface roughness meter ET-4000A, the maximum waviness valley depth was 1.1 μm.
The stiffness of the produced thermal transfer image-receiving sheet of Comparative Example 20 was 0.98 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Comparative Example 21)
A thermal transfer image receiving sheet of Comparative Example 21 was obtained in the same manner as Comparative Example 17 except that the same paper base material as in Example 1 was used.
Separately, after forming a smooth layer of the thermal transfer image-receiving sheet of Comparative Example 21, a transfer body and a thermal simulator were used to transfer a solid image at an energy of 300 dpi, 10 msec / line, and 0.5 mJ / dot. The optical reflection density of the surface of the transferred smooth layer was measured by X-rite 528, and it was 1.30.
When the thermal transfer image receiving sheet of Comparative Example 21 was measured with a contact type surface roughness meter ET-4000A, the maximum waviness valley depth was 0.9 μm.
The stiffness of the produced thermal transfer image-receiving sheet of Comparative Example 21 was measured using a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.), and the stiffness was 1.08 mN · m.

(Comparative Example 22)
A thermal transfer image-receiving sheet of Comparative Example 22 was obtained in the same manner as Comparative Example 18 except that the same paper substrate as in Example 1 was used.
Separately, after forming a smooth layer of the thermal transfer image-receiving sheet of Comparative Example 22, a solid image was transferred at an energy of 300 dpi, 10 msec / line, and 0.5 mJ / dot using a transfer body and a thermal simulator. The optical reflection density of the surface of the transferred smooth layer was measured by X-rite 528, and it was 1.30.
When the thermal transfer image receiving sheet of Comparative Example 22 was measured by a contact type surface roughness meter ET-4000A, the maximum waviness valley depth was 0.8 μm.
The stiffness of the prepared thermal transfer image-receiving sheet of Comparative Example 22 was 1.18 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Comparative Example 23)
A thermal transfer image-receiving sheet of Comparative Example 23 was obtained in the same manner as in Comparative Example 19 except that the same paper base material as in Example 1 was used.
Separately, after forming the smooth layer of the thermal transfer image-receiving sheet of Comparative Example 23, a solid image was transferred at an energy of 300 dpi, 10 msec / line and 0.5 mJ / dot using a transfer body and a thermal simulator. The optical reflection density of the surface of the transferred smooth layer was measured by X-rite 528, and it was 1.30.
When the thermal transfer image receiving sheet of Comparative Example 23 was measured with a contact type surface roughness meter ET-4000A, the maximum waviness valley depth was 0.6 μm.
The stiffness of the produced thermal transfer image-receiving sheet of Comparative Example 23 was 1.08 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Comparative Example 24)
A polyethylene resin (LC600A manufactured by Nippon Polyethylene Co., Ltd.) having a thickness of 30 μm was extruded on one surface of the same paper base material as in Example 1 by a melt extrusion method, and the polyethylene resin was used as the paper base material 1 and the PET film (Lumirror F65). The pieces were stuck together by the sandwich method so that they were sandwiched by # 12).
Then, on the other surface of the paper substrate 1, a polyethylene resin (LC600A manufactured by Nippon Polyethylene Co., Ltd.) was placed between the foamed polypropylene film (Econage NW2, manufactured by Mitsui Chemicals Tohcello Co., Ltd.) and the porous layer. It was melt-extruded to form a smooth layer, which was then laminated by a sand lamella method.
After forming the porous layer as described above, the image receiving layer was the same as in Example 1 to obtain a thermal transfer image receiving sheet of Comparative Example 24.
Separately, after forming a smooth layer of the thermal transfer image-receiving sheet of Comparative Example 24, a solid image was transferred at an energy of 300 dpi, 10 msec / line and 0.5 mJ / dot using a transfer body and a thermal simulator. The optical reflection density of the surface of the transferred smooth layer was measured by X-rite 528, and it was 1.30.
When the thermal transfer image receiving sheet of Comparative Example 24 was measured with a contact type surface roughness meter ET-4000A, the maximum waviness valley depth was 1.0 μm.
The stiffness of the produced thermal transfer image-receiving sheet of Comparative Example 24 was 1.76 mN · m as measured by a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.).

(Evaluation)
When the thermal transfer image receiving sheet transfer bodies of Examples 1 to 5 and Comparative Examples 1 to 24 were measured for stiffness using a Taber stiffness tester (manufactured by Toyo Seiki Co., Ltd.), the stiffness was 1.96 mN · m. As compared with the salt photograph, the koshi was evaluated according to the following criteria.
[Rigid judgment criteria]
◯: It is firmer than the silver salt photograph.
Δ: There is elasticity close to that of a silver salt photograph, but I feel that it is insufficient.
X: From the silver salt photograph, it is felt that the body is definitely lacking. Alternatively, it is too stiff to be wrapped around a 3-inch paper tube.

(Mura evaluation)
Solid images were transferred from the thermal transfer image-receiving sheet transfer bodies of Examples 1 to 5 and Comparative Examples 1 to 24 using a transfer body and a thermal simulator at an energy of 300 dpi, 10 msec / line, and 0.1 mJ / dot. The state of unevenness at that time was visually evaluated according to the following criteria.
[Mottling criteria]
◯: A good printed image can be obtained without unevenness in light and shade.
Δ: White spots cannot be visually confirmed, but light and shade are visible.
X: White spots can be visually confirmed.

(Show-through evaluation)
Solid images were transferred from the thermal transfer image receiving sheet transfer bodies of Examples 1 to 5 and Comparative Examples 1 to 24 using a transfer body and a thermal simulator at an energy of 300 dpi, 10 msec / line, and 0.5 mJ / dot. Then, it was stored for 1 week in an environment of a temperature of 40 ° C. and a humidity of 90% RH. After storage, the surface opposite to the transferred surface was visually observed and visually evaluated according to the following criteria.
[Clearance criteria]
◯: The transferred image cannot be confirmed.
Δ: The transferred image is slightly visible.
X: The transferred image can be clearly confirmed.

(Manufacturing cost evaluation)
[Cost judgment criteria]
The manufacturing costs of the thermal transfer image-receiving sheets of Examples 1 to 5 and Comparative Examples 1 to 24 were evaluated according to the following criteria.
◯: From the viewpoint of material cost and manufacturing cost, it can be manufactured at a lower cost than before.
X: From the viewpoint of material cost and manufacturing cost, it cannot be manufactured at a lower cost than conventional.

  Table 1 shows the configuration and the result of the evaluation.

As can be seen from the results in Table 1, when the optical reflection density is 1.3 or more, the smooth layer is easily dyed. That is, strikethrough occurs in Comparative Examples 1 to 8 and Comparative Examples 17 to 24. In Comparative Example 9 in which the optical reflection density is 0.11, strike-through is slightly generated, but when the density is 0.1 or less, it can be confirmed that the backing is eliminated as in Examples 1-5. It was
Further, from the results of Comparative Examples 9 and 16, it was found that unevenness was a concern when the maximum waviness valley depth of the thermal transfer image receiving sheet was 1.3 μm.
Regarding the stiffness of the thermal transfer image-receiving sheet, from the result of Comparative Example 14, when the stiffness is less than 1.37 mN · m, a lack of stiffness is felt, and the stiffness of Example 1 is 1.47 mN · m or more and the stiffness is satisfied. I understood. However, in Comparative Examples 10 and 11 having a stiffness of more than 2.94 mN · m, it was difficult to wind it around a 3-inch paper tube, so it was judged that the stiffness of 2.94 mN · m was preferable.
Also, the effect of the present invention was confirmed from the viewpoint of manufacturing cost.

The thermal transfer image-receiving sheet obtained according to the present invention can be used in a sublimation transfer type printer and can easily form various images in full color. Therefore, it can be used for self-printing of digital cameras, cards such as identification cards, and amusement. It can be widely used for output materials.

100: Paper substrate 200: Smooth layer 300: Porous layer 400: Image receiving layer

Claims (1)

A thermal transfer image-receiving sheet having an image-receiving layer on at least one surface side of a paper substrate,
The surface of the image receiving layer constitutes the outermost surface,
The Taber stiffness (JIS-P8125: 2000) of the thermal transfer image-receiving sheet is 1.47 mN · m or more and 2.94 mN · m or less, and the maximum valley depth Wv (ISO4287-1997) of the waviness curve of the surface of the image-receiving layer is Less than 1.3 μm,
Further, between the paper base material and the image receiving layer, at least a porous layer and a smooth layer,
The smooth layer is a layer having an optical reflection density of 0.1 or less when the transfer member is thermally transferred at a speed of 300 dpi, a speed of 10 msec / line, and an energy of 0.5 mJ / dot. Thermal transfer image receiving sheet.

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