JP6627439B2 - Thermal transfer sheet - Google Patents

Description

  The present invention relates to a thermal transfer sheet used for a thermal transfer type printer or the like, and in particular, a thermal transfer sheet having a heat-resistant lubricating layer formed on one surface of a substrate and a thermal transfer layer formed on the other surface of the substrate. Regarding the sheet.

  Generally, a thermal transfer sheet is called a thermal ribbon and is an ink ribbon used for a thermal transfer type printer. A thermal transfer layer is provided on one surface of a base material, and a heat-resistant transfer layer is provided on the other surface of the base material. It is provided with a lubricating layer (backcoat layer).

  Here, the thermal transfer layer is an ink layer, and the ink is sublimated (in the case of the sublimation transfer system) or melted (in the case of the melt transfer system) by heat generated in the thermal head of the printer, and is transferred to the transfer target side. Is transferred to

  At present, among the thermal transfer methods, the sublimation transfer method can easily form full-color images of various types in conjunction with the enhancement of printer functions, so it can be used for self-printing of digital cameras, cards such as identification cards, and output for amusement. Widely used for things.

  With the diversification of the above-mentioned applications of the thermal transfer sheet, there has been a growing demand for miniaturization, high speed, low cost, environmental compatibility, and durability of the obtained printed matter. 2. Description of the Related Art A thermal transfer sheet having a plurality of thermal transfer layers, in which a protective layer or the like for imparting durability to a print is provided so as not to overlap on the same surface, is widely used.

  Under these circumstances, with the diversification and widespread use of applications, as the printing speed of printers has been further increased and the amount of dye used for cost reduction has been reduced, sufficient printing density can be obtained with conventional thermal transfer sheets. There is a problem that is not possible.

  Therefore, in order to increase the transfer sensitivity, attempts have been made to improve the transfer sensitivity in printing by increasing the output of the printer.However, during printing, wrinkles are generated on the heat transfer sheet due to heat or pressure, and in some cases, There is a problem that rupture occurs.

  Such defects such as generation of wrinkles and breakage are caused by damage to the thermal transfer sheet by heat applied to the thermal transfer sheet by the thermal head during printing and friction between the thermal transfer sheet and the thermal head.

  In order to solve such a defect, Patent Document 1 proposes a method using a lubricating layer made of granular ester wax.

  However, when such a thermal release agent is added to the heat-resistant lubricating layer, the thermal release agent is transferred to the facing heat-sensitive transfer layer or protective layer, particularly during storage in a rolled state, and the printing density is reduced. There are problems such as causing abnormalities and poor transfer.

  Therefore, in Patent Document 2, the lubricity of a heat-resistant lubricating layer is improved by adding a copolymer of a reactive silicone and a vinyl monomer as a lubricant to a UV-curable resin to a self-crosslinking acrylic resin. In addition, a heat-resistant lubricating layer having excellent mechanical strength and excellent Si migration resistance has been proposed.

Further, there is a problem that scum derived from the heat-resistant lubricating layer is accumulated in the thermal head during thermal transfer. When scum accumulates on the thermal head, the heat from the thermal head is not sufficiently transmitted to the thermal transfer sheet, and printing is not performed at a portion where printing is to be performed, resulting in a white streak-like defect. In order to solve such a defect, Patent Document 3 proposes adding fine particles to a heat-resistant lubricating layer for the purpose of removing soot adhering to a head, that is, imparting a so-called head cleaning property to a thermal transfer sheet. ing.

Japanese Patent Publication No. 6-75999 JP 2001-171248 A JP-A-6-316172 JP-A-2015-107640 Japanese Patent No. 4962504

  For the purpose of imparting head cleaning properties to the heat-resistant lubricating layer, fine particles as described in Patent Document 3 are added to the heat-resistant lubricating layer in which the resin constituting the heat-resistant lubricating layer itself has slipperiness as in Patent Document 2 described above. In this case, it is necessary to adopt a structure in which fine particles are buried in the heat-resistant lubricating layer in order to achieve both the head cleaning property and the slipperiness of the heat-resistant lubricating layer. However, when the ribbon having the heat-resistant lubricating layer having such a structure is stored in a rolled state, the convex portion generated by covering the fine particles with the resin of the heat-resistant lubricating layer comes into contact with the color surface, so that the color surface has There is a possibility that so-called set-off, in which the dye is transferred to the heat-resistant lubricating layer, or so-called set-off, in which the dye set off when the ribbon is wound, is further transferred to the heat-sensitive transfer layer or the transferable protective layer.

  The present invention provides a heat-resistant lubricating layer binder resin for the purpose of preventing wrinkles and breakage of the thermal transfer sheet, while preserving even when fine particles are added to the heat-resistant lubricating layer for the purpose of imparting head cleaning properties. It is an object of the present invention to provide a thermal transfer sheet capable of preventing dye transfer to the heat-resistant lubricating layer at the time.

  Note that Patent Document 4 describes that the heat-resistant lubricating layer contains spherical fine particles and flat fine particles. The flat fine particles have an average diameter and an aspect ratio, but do not describe the thickness. This is presumably because the object of the present invention is to make peelability and transport flaws a problem.

  Patent Document 5 also discloses that the heat-resistant lubricating layer contains spherical fine particles and flat fine particles, but the flat fine particles have an average diameter and an aspect ratio, but the thickness and the surface modification of the spherical fine particles are described. There is no statement about. This is presumably because tabular grains do not protrude while maintaining lubricity.

The invention according to claim 1 of the present invention comprises at least a substrate, a heat-resistant lubricating layer formed on one surface of the substrate, and a heat-sensitive transfer layer formed on the other surface of the substrate. ,
The heat-resistant slip layer,
The binder mainly consists of a reaction product of a reactive silicone oil and a radical polymerization type curable resin,
And containing flat inorganic fine particles and spherical fine particles whose surface is modified by a silane coupling agent,
When the flat inorganic fine particles have a thickness t and a width in a direction perpendicular to the thickness t is a diameter d, the ratio (d _min / t) of the minimum diameter d _min to the thickness t of the diameter d is 2 or more. Some shape,
Further, a thermal transfer sheet is provided, wherein the ratio (t / r) of the average thickness t of the flat inorganic fine particles to the average particle size r of the spherical fine particles is 1.0 or more.

The invention according to claim 2 of the present invention is characterized in that the flat inorganic fine particles have a cleavage property such that the flat inorganic fine particles have a cleavage plane that is horizontal to the flat surface of the flat inorganic fine particles. A thermal transfer sheet is provided.

  The invention according to claim 3 of the present invention provides the thermal transfer sheet according to claim 1 or 2, wherein the flat inorganic fine particles have a Mohs hardness of less than 4.

The invention according to claim 4 of the present invention is characterized in that the heat-resistant lubricating layer contains the spherical fine particles and the tabular inorganic fine particles in an amount of 3% or more of the total weight of the heat-resistant lubricating layer.
4. The thermal transfer sheet according to claim 1, wherein the total content of the spherical fine particles and the flat inorganic fine particles is 25% or less of the total weight of the heat-resistant lubricating layer. 5.

  According to one aspect of the present invention, fine particles are added to the heat-resistant lubricating layer for the purpose of imparting head cleaning properties, while imparting slipperiness to the heat-resistant lubricating layer binder resin for the purpose of preventing wrinkles and breakage of the thermal transfer sheet. Even in this case, a thermal transfer sheet capable of preventing dye transfer to the heat-resistant lubricating layer during storage can be provided.

FIG. 1 is a cross-sectional view illustrating an example of a schematic configuration of a thermal transfer sheet according to an embodiment of the present invention.

  In the following detailed description, numerous specific details are set forth to provide a thorough understanding of embodiments of the present invention. It is apparent, however, that one or more embodiments may be practiced without these specific details. Other well-known structures and devices are schematically illustrated in order to simplify the drawings.

  Hereinafter, an embodiment of the present invention (hereinafter, referred to as “the present embodiment”) will be described with reference to the drawings.

(overall structure)
FIG. 1 is a cross-sectional view illustrating an example of a schematic configuration of the thermal transfer sheet of the present embodiment.

  As shown in FIG. 1, the thermal transfer sheet 1 includes a substrate 10, a heat-resistant lubricating layer 30 formed on one surface of the substrate 10, and a heat-sensitive transfer layer 20 formed on the other surface of the substrate 10. And

(Configuration of the base material 10)
The base material 10 is required to have heat resistance and strength so as not to be softened and deformed by the heat pressure in thermal transfer.

  For this reason, as a material of the base material 10, for example, a film of a synthetic resin such as polyethylene terephthalate, polyethylene naphthalate, polypropylene, cellophane, acetate, polycarbonate, polysulfone, polyimide, polyvinyl alcohol, aromatic polyamide, aramid, and polystyrene; and Papers such as condenser paper and paraffin paper can be used alone or as a combined composite. Particularly, in consideration of physical properties, workability, cost, and the like, among the above-mentioned materials, a polyethylene terephthalate film is preferable.

  The thickness of the substrate 10 (the length in the vertical direction in FIG. 1) may be in the range of 2 μm or more and 50 μm or less in consideration of operability and workability. Particularly, in consideration of handling properties such as transfer suitability and workability, those having a size of about 2 μm or more and 9 μm or less are preferable.

  In addition, of the base material 10, the surface on which the heat-resistant lubricating layer 30 is formed (the lower surface in FIG. 1) and the surface on which the heat-sensitive transfer layer 20 is formed (in FIG. The upper surface of the material 10) may be subjected to an adhesive treatment, and the surface to be subjected to the adhesive treatment may be either one or both.

  As the above-mentioned bonding treatment, known techniques such as corona treatment, flame treatment, ozone treatment, ultraviolet treatment, radiation treatment, surface roughening treatment, plasma treatment, and primer treatment can be applied. It is also possible to use two or more kinds in combination.

(Configuration of heat-resistant lubricating layer 30)
The heat-resistant lubricating layer 30 is a layer formed on one surface of the base material 10 and is a layer that imparts lubricity between the thermal transfer sheet 1 and a thermal head.

  In the thermal transfer sheet 1 according to the embodiment of the present invention, the binder 31 constituting the heat-resistant lubricating layer 30 is improved in lubricity by a cured product of a radical polymerization type curable resin and a reactive silicone oil, The spherical fine particles 32 added to the heat-resistant lubricating layer 30 are surface-modified with a coupling agent, so that the affinity for the heat-resistant lubricating layer with the radical polymerizable curable resin and the binder 31 composed of a cured product of the lubricant is obtained. In addition to the configuration in which the spherical fine particles 32 are covered with the binder 31, the average thickness t of the flat inorganic fine particles 33 added to the heat-resistant lubricating layer 30 is It is characterized by being larger than the average particle size r.

  In the heat-resistant lubricating layer 30 according to the embodiment of the present invention, the binder 31 contained in the heat-resistant lubricating layer 30 is mainly formed of a reaction-cured product of a radical polymerizable curable resin and a reactive silicone oil as a lubricant. By using a reaction cured product of the radical polymerization type curable resin and the lubricant as the binder 31, the lubricity of the heat-resistant lubricating layer can be improved, and the friction between the thermal head and the thermal transfer sheet during printing can be reduced. Can be done. At the same time, since the silicone oil reacts with the radically polymerizable curable resin, the transfer of the lubricant component to the heat-sensitive transfer layer or the protective layer is prevented even during storage in a rolled state, and abnormal print density and transfer. Failure can be prevented.

  The radical polymerization type curable resin is a resin which is cured by elongation of a polymer chain starting from a radical generated by irradiation with ionizing radiation or ultraviolet rays. Examples include lauryl acrylate, stearyl acrylate, carboxyethyl acrylate, isobonyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, n-lauryl methacrylate, monofunctional acrylates such as alkyl methacrylate, and monofunctional methacrylates, triethylene glycol diacrylate, Trifunctional or higher polyfunctional such as bifunctional acrylate and bifunctional methacrylate such as polyethylene glycol diacrylate and ethoxylated bisphenol A diacrylate, ethoxylated isocyanuric acid triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, and dipentaerythritol hexaacrylate Acrylate or polyfunctional methacrylate monomer or And, although oligomers consisting of the monomers include, but are not limited to the above.

  Further, a photopolymerization initiator can be added in order to cure the radical polymerization type curable resin by irradiation with ultraviolet rays. The photopolymerization initiator is a compound that is activated by UV or the like and starts a radical reaction of the radical polymerization type curable resin. The photopolymerization initiator is preferably used in an amount of 10 parts by weight or less based on 100 parts by weight of the radical polymerization type curable resin.

  The reactive silicone oil is obtained by replacing some methyl groups of dimethylpolysiloxane with reactive functional groups. The reactive silicone oil is classified into side chain modified type, one terminal modified type, both terminal modified type, side chain both terminal type, etc., depending on the position of the functional group.In the present invention, any of the classified silicone oils is used. Can be used. From the viewpoint of the reactivity with the resin and the stability of the reactant, a silicone oil modified at both ends or a silicone oil having both side chains at both ends is particularly preferred.

  The surface of the spherical fine particles 32 is modified with a silane coupling agent, so that the affinity for the binder 31, which is an organic substance and is made of a reactive cured product of a radical polymerization type curable resin and a reactive silicone oil, is improved. As a result, a state is obtained in which the surface of the fine particles is coated with the binder 31. Therefore, during printing, the surface of the spherical fine particles 32 having low lubricity does not come into direct contact with the thermal head, so that the friction between the thermal head and the heat-resistant lubricating layer during printing can be reduced.

  The surface of the spherical fine particles 32 is modified with the silane coupling agent. The silane coupling agent generally has three methyl groups, or a hydrolyzable group such as a methoxy group, an ethoxy group, or an acetoxy group, and one amino group, an epoxy group, a methacryl group, or a vinyl group around a Si atom. It is a substance having a structure having a functional group that reacts with an organic substance such as. The methyl group or the hydrolyzable group of the silane coupling agent and the functional group that reacts with an organic substance can be arbitrarily selected within the above range, and the functional group particularly improves the affinity with the reaction cured product. From the viewpoint that the methacrylic group having a C ＝ C unsaturated bond can be preferably used at the terminal.

  As a method of surface modification of the spherical fine particles 32 with a silane coupling agent, a direct treatment method in which the fine particles are modified with a silane coupling agent before adding the fine particles to the resin, and a silane coupling agent when the fine particles are added to the resin. Although there is an integral blend method or the like to be added, a direct treatment method is preferred from the viewpoint that the dispersibility of the fine particles and the incorporation of a reaction by-product between the fine particles and the silane coupling agent can be suppressed.

  The “spherical shape” of the spherical microparticles 32 is not necessarily limited to a true spherical shape, and the cross-sectional shape of the particle may be a shape formed by a curved surface such as a circle, an ellipse, a substantially circular shape, or a substantially elliptical shape. Means that.

  The ratio (t / r) of the average thickness t of the flat inorganic fine particles 33 to the average particle diameter r of the spherical fine particles is 1.0 or more. That is, by making t larger than r, it is possible to prevent the heat-resistant lubricating layer binder 31 covering the spherical fine particles from coming into contact with the facing thermal transfer layer 20 when the thermal transfer sheet is stored in a wound state. As a result, it is possible to prevent the transfer of the dye from the heat-sensitive transfer layer to the heat-resistant lubricating layer. The average thickness of the flat inorganic fine particles is obtained by measuring the thickness of the flat inorganic fine particles using a scanning electron microscope (SEM) and calculating the average thickness of 100 or more flat inorganic fine particles. . The average particle diameter of the spherical fine particles is obtained by measuring the particle diameter distribution on a volume basis using a laser diffraction / scattering method and calculating the particle diameter at which the cumulative% becomes 50%.

It should be noted that "flat" of the flat inorganic particle 33, the thickness horizontal plane parallel or substantially parallel of a second surface or the combination of a generally horizontal plane, the width in the direction Cartesian to both sides When t is the width in the direction perpendicular to the thickness t and d is the diameter, it means that the ratio of the minimum diameter d _min to the thickness t (d _min / t) is 2 or more.

In addition, the flat inorganic fine particles 33 preferably have a cleavage property such that the flat inorganic fine particles 33 have a cleavage plane that is horizontal to the flat surface of the flat inorganic fine particles. By using fine particles having such a cleavage property, at the time of printing, the plate-like inorganic fine particles 33 easily come off in parallel with the surface of the heat-resistant lubricating layer and the height thereof becomes low. The spherical fine particles 32 coated on the functional layer binder 31 come into contact with each other, and as a result, it is possible to obtain high slipperiness and cleaning properties.

  Preferably, the plate-like inorganic fine particles 33 have a Mohs hardness of less than 4. Since the Mohs hardness of the flat inorganic fine particles 33 is smaller than 4, the thermal head is not damaged even when the flat inorganic fine particles come into contact with the thermal head. It is possible to keep getting.

  The content of each of the spherical fine particles 32 and the flat inorganic fine particles 33 is 3% or more of the weight of the entire heat-resistant lubricating layer, and the total content of the spherical fine particles 32 and the flat inorganic fine particles 33 is Is preferably 25% or less of the weight of the entire heat-resistant lubricating layer. When the content of the spherical fine particles is less than 3%, it is difficult to obtain sufficient head cleaning properties. When the content of the tabular inorganic fine particles is less than 3%, it is difficult to sufficiently prevent the transfer of the dye from the heat-sensitive transfer layer to the heat-resistant lubricating layer. When the total content of the spherical fine particles and the flat inorganic fine particles exceeds 25%, the strength of the heat-resistant lubricating layer is reduced, and the possibility of occurrence of defects such as wrinkles and breakage increases.

  The heat-resistant lubricating layer 30 contains, in addition to the radical-polymerizable curable resin, the lubricant, the fine particles and the flat inorganic fine particles, additives such as a filler, an antistatic agent, and a radical polymerization initiator as long as the performance is not impaired. It can be blended as needed.

  The heat-resistant lubricating layer 30 is formed by dissolving or dispersing, in a solvent or a resin monomer, a material in which an additive is added as necessary, in addition to the above-described radical polymerization type resin, lubricant, spherical fine particles and flat inorganic fine particles. It is possible to prepare the applied coating liquid, apply, dry and / or cure it to form the coating liquid.

The coating amount of the heat-resistant lubricating layer 30 after drying is suitably about 0.1 g / m ² or more and about 2.0 g / m ² or less.

  Here, the applied amount of the heat-resistant lubricating layer 30 after drying indicates the amount of solid content remaining after applying a coating liquid for forming the heat-resistant lubricating layer 30 and drying and / or curing. Similarly, the coating amount after drying of the heat-sensitive transfer layer 20 described later indicates the amount of solid content remaining after the coating liquid is applied and dried.

(Configuration of Thermal Transfer Layer 20)
The heat-sensitive transfer layer 20 is a layer formed on the surface of the substrate 10 opposite to the surface on which the heat-resistant lubricating layer 30 is formed. For example, the heat-sensitive transfer layer 20 contains a heat transfer dye, a binder, a solvent, and the like. A coating liquid for forming the thermal transfer layer 20, that is, a coating liquid for forming the thermal transfer layer is prepared, applied, and dried.

  The heat transfer dye is a dye that melts, diffuses, or sublimates by heat.

  Among the heat transfer dyes, examples of the yellow component include C.I. I. Solvent Yellow 56, 16, 30, 93, 33, C.I. I. Disperse Yellow 201, 231, 33 and the like can be used.

  Among the heat transfer dyes, examples of the magenta component include C.I. I. Disperse Violet 26, 31, C.I. I. Disperse Red 60, C.I. I. Solvent Red 19, 27 or the like can be used.

  Further, among the heat transferable dyes, as the cyan component, for example, C.I. I. Disperse Blue 24, 257, 354, C.I. I. Solvent Blue 36, 63, 266 or the like can be used.

  It is to be noted that, as a black dye, it is general to perform toning by combining the above-described dyes.

  As the resin contained in the heat-sensitive transfer layer 20, any of conventionally known resin binders can be used, and is not particularly limited. Ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxycellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate Cellulose resins such as polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl pyrrolidone, vinyl resins such as polyacrylamide, polyester resins, styrene-acrylonitrile copolymer resins, phenoxy resins and the like can be used. .

  Here, the mixing ratio of the dye and the resin of the thermal transfer layer 20 is preferably (dye) / (resin) = 10/100 or more and 300/100 or less on a mass basis.

  This is because if the ratio of (dye) / (resin) is less than 10/100, the amount of the dye is too small and the color density is insufficient, so that a good thermal transfer image cannot be obtained. If the amount exceeds the above range, the solubility of the dye in the resin is extremely reduced, so that when the sheet is formed into a thermal transfer sheet, the storage stability is deteriorated, and the dye is easily precipitated.

  The thermal transfer layer 20 may contain known additives such as an isocyanate compound, a silane coupling agent, a dispersant, a viscosity modifier, and a stabilizer as long as the performance is not impaired.

The coating amount of the thermal transfer layer 20 after drying is suitably about 1.0 g / m ² . Note that the thermal transfer layer 20 can be configured as a single layer of one color, and a plurality of thermal transfer layers 20 containing dyes having different hues are sequentially formed on the same surface of the same base material 10. It can be formed repeatedly.

  In addition, between the base material 10 and the heat-sensitive transfer layer 20 and between the base material 10 and the heat-resistant lubricating layer 30, the purpose is to provide functionality such as improvement in adhesion and improvement in dye use efficiency. It is also possible to provide further layers.

  The heat-resistant lubricating layer 30 and the heat-sensitive transfer layer 20 can be formed by applying a conventionally known coating method, and drying and / or curing.

  As a coating method, for example, a gravure coating method, a screen printing method, a spray coating method, a reverse roll coating method, and a die coating method can be used.

  By using the thermal transfer sheet 1 having the above characteristics, it is possible to impart high lubricity while providing head cleaning properties, to prevent wrinkles and breakage during printing, and to prevent migration of lubricant components. Prevention of printing density abnormality and transfer failure can be prevented.

Although the present invention has been described with reference to the specific embodiments, the present invention is not limited by these descriptions. Other embodiments of the invention, as well as various modifications of the disclosed embodiments, will be apparent to persons skilled in the art upon reference to the description of the invention. Therefore, it is to be understood that the appended claims also cover these modifications and embodiments that fall within the scope and spirit of the present invention.

  Hereinafter, the effects of the thermal transfer sheet 1 in the embodiment of the present invention will be verified using Examples 1 to 10 and Comparative Examples 1 to 7 with reference to FIG. In the following description, when “part” is described, unless otherwise specified, it is based on weight. Further, the present invention is not limited to the following embodiments.

  In Examples and Comparative Examples described below, transfer sheets for thermal transfer were prepared by the following method.

<Preparation of transfer object>
As a base material, a 190 μm double-sided resin-coated paper was used, and a heat-insulating layer coating solution having the following composition was applied on one surface thereof by a die coating method so that the coating amount after drying was 8.0 g / m ^2. And then dried to form a heat insulating layer, and then, on the upper surface of the heat insulating layer, a coating amount of the image receiving layer having the composition shown below is applied by gravure coating method to a coating amount of 4.0 g / m ² after drying. Then, the coated material was dried and dried to prepare a transfer body for thermal transfer.

(Heat insulation layer coating solution)
Acrylic-styrene hollow particles 35.0 parts (average particle diameter 1 μm, volume hollow ratio 51%)
Styrene-butadiene rubber 10.0 parts Pure water 55.0 parts Dispersant trace amount Antifoaming agent trace amount The above is the composition.

(Image receiving layer coating solution)
Vinyl chloride-vinyl acetate-vinyl alcohol copolymer 19.5 parts Amino-modified silicone oil 0.5 parts Toluene 40.0 parts Methyl ethyl ketone 40.0 parts The composition is as described above.

<Treatment of spherical fine particles with silane coupling agent>
An aqueous solution of a silane coupling agent having the following composition was prepared by diluting a silane coupling agent KBM-5103 having an acrylic group as a functional group with pure water.

  As spherical fine particles, silica fine particles having an average particle size of 0.05 μm (Sciqas grade 0.05 μm, manufactured by Sakai Chemical Industry Co., Ltd.) were used, and while stirring with a Henschel mixer, 5 parts of an aqueous solution of a silane coupling agent was added to 100 parts of the fine particles. And sprayed in the form of a mist to add a silane coupling agent. After the total amount of the aqueous solution of the silane coupling agent was added, the mixture was further stirred for 10 minutes, and then dried at 120 ° C. for 1 hour to obtain silane-coupled silica fine particles 1.

(Silane coupling agent aqueous solution)
Silane coupling agent (KBM-5103 manufactured by Shin-Etsu Silicone Co., Ltd.) 20.0 parts Pure water 80.0 parts The composition is as follows.

<Example 1>
A 4.5 μm thick polyethylene terephthalate film with a single-sided easy-adhesion treatment was used as the substrate 10, and a coating solution having the composition shown below was applied to the non-adhesion-treated surface of the polyethylene terephthalate film, and the heat-resistant slip layer 30 of Example 1 It was applied by a gravure coating method as a coating liquid for forming. At this time, application was performed so that the application amount after curing was 0.5 g / m ² . After the application, the mixture was purged with nitrogen and then irradiated with UV using an ultraviolet irradiation device (Fusion UV System Japan Light Source H-Bulb) so that the integrated light amount became 380 mJ / m ² , thereby forming a heat-resistant lubricating layer 30. Hereinafter, the coating liquid for forming the heat-resistant lubricating layer 30 of Example 1 is referred to as “coating liquid-1 for forming a heat-resistant lubricating layer”.

A coating solution having the following composition was applied to the surface of the substrate on which the heat-resistant lubricating layer 30 was formed, on which the heat-resistant lubricating layer 30 was to be easily adhered, by a gravure coating method as a coating solution for forming the heat-sensitive transfer layer 20. At that time, the heat transfer sheet 20 of Example 1 was obtained by applying so that the coating amount after drying was 0.70 g / m ² and drying at a temperature of 90 ° C. for 1 minute. Was. Hereinafter, the coating solution for forming the thermal transfer layer 20 is referred to as a “thermal transfer layer coating solution”.

(Coating liquid for forming heat-resistant lubricating layer-1)
Acrylic monomer (Light acrylate PE-4A manufactured by Kyoeisha Chemical Co., Ltd.)
87.0 parts Acrylic-modified silicone oil (X-22-1602 manufactured by Shin-Etsu Silicone Co., Ltd.)
2.0 parts Silane-coupled silica fine particles 1 5.0 parts Talc (P-6, manufactured by Nippon Talc) 5.0 parts Photopolymerization initiator (Irgacure 184, manufactured by BASF) 1.0 part The composition is as described above.

(Thermal transfer layer coating solution)
C. I. Solvent Blue 63 6.0 parts Polyvinyl acetal resin 4.0 parts Toluene 45.0 parts Methyl ethyl ketone 45.0 parts The composition is as described above.

<Example 2>
In the thermal transfer sheet 1 prepared in Example 1, the same procedure as in Example 1 was performed, except that the coating liquid-1 for forming a heat-resistant slip layer was replaced with a coating liquid having the following composition to form the heat-resistant slip layer 30. By the procedure, the thermal transfer sheet 1 of Example 2 was obtained. The coating liquid for forming the heat-resistant lubricating layer 30 of Example 2 is referred to as “heat-resistant lubricating layer forming coating liquid-2”.

(Heat-resistant lubricating layer forming coating liquid-2)
Acrylic monomer (Light acrylate DPE-6A manufactured by Kyoeisha Chemical Co., Ltd.)
87.0 parts Methacryl-modified silicone oil (X-22-164B manufactured by Shin-Etsu Silicone Co., Ltd.)
2.0 parts Silane-coupled silica fine particles 1 5.0 parts Talc (P-6, manufactured by Nippon Talc) 5.0 parts Photopolymerization initiator (Irgacure 184, manufactured by BASF) 1.0 part The composition is as described above.

<Example 3>
In the thermal transfer sheet 1 prepared in Example 1, a coating liquid for forming a heat-resistant lubricating layer having the above composition was prepared.
Zinc oxide fine particles (Finex manufactured by Sakai Chemical Industry Co., Ltd.) were obtained by converting the spherical fine particles added to No. 1 from “silane-coupled silica fine particles 1” obtained by treating a silica fine particle, Squiqas grade 0.05 μm, with a silane coupling agent KBM-5103. -25 average particle diameter 0.06 μm) was replaced with “silane-coupled ZnO fine particles” treated in the same manner with a silane coupling agent having a methacryl group as a functional group (KBM-502 manufactured by Shin-Etsu Silicone Co., Ltd.). Except for this, the thermal transfer sheet 1 of Example 3 was obtained in the same procedure as in Example 1. Hereinafter, the coating liquid for forming the heat-resistant lubricating layer 30 of Example 3 is referred to as “coating liquid-3 for forming a heat-resistant lubricating layer”.

(Coating solution-3 for forming heat-resistant lubricating layer)
Acrylic monomer (Light acrylate PE-4A manufactured by Kyoeisha Chemical Co., Ltd.)
87.0 parts Acrylic-modified silicone oil (X-22-1602 manufactured by Shin-Etsu Silicone Co., Ltd.)
2.0 parts Silane-coupled ZnO fine particles 5.0 parts Talc (P-6 manufactured by Nippon Talc) 5.0 parts Photopolymerization initiator (Irgacure 184 manufactured by BASF) 1.0 part The composition is as described above.

<Example 4>
In the thermal transfer sheet 1 prepared in Example 1, spherical fine particles added to the heat-resistant lubricating layer forming coating solution-1 having the above-mentioned composition were coated with a silica fine particle, Sciqas grade 0.05 μm, using a silane coupling agent KBM-5103. From the treated “silane-coupled silica fine particles 1”, silica fine particles (Sciqas grade 0.1 μm, average particle size 0.1 μm, manufactured by Sakai Chemical Industry Co., Ltd.) were converted to a silane coupling agent having a methacryl group as a functional group (Shin-Etsu Silicone). The thermal transfer sheet 1 of Example 4 was obtained in the same procedure as in Example 1 except that KBM-5103 manufactured by K.K. was used instead of the “silane-coupled silica fine particles 2” treated in the same manner. Hereinafter, the coating liquid for forming the heat-resistant lubricating layer 30 of Example 4 is referred to as “coating liquid-4 for forming a heat-resistant lubricating layer”.

(Coating solution-4 for forming heat-resistant lubricating layer)
Acrylic monomer (Light acrylate PE-4A manufactured by Kyoeisha Chemical Co., Ltd.)
87.0 parts Acrylic-modified silicone oil (X-22-1602 manufactured by Shin-Etsu Silicone Co., Ltd.)
2.0 parts Silane-coupled silica fine particles 2 5.0 parts Talc (P-6 manufactured by Nippon Talc) 5.0 parts Photopolymerization initiator (Irgacure 184 manufactured by BASF) 1.0 part The composition is as described above.

<Example 5>
In the thermal transfer sheet 1 prepared in Example 1, the same procedure as in Example 1 was performed, except that the coating liquid-1 for forming a heat-resistant slip layer was replaced with a coating liquid having the following composition to form the heat-resistant slip layer 30. By the procedure, the thermal transfer sheet 1 of Example 5 was obtained. Hereinafter, the coating liquid for forming the heat-resistant lubricating layer 30 of Example 5 is referred to as “coating liquid-5 for forming a heat-resistant lubricating layer”.

(Coating solution-5 for forming heat-resistant lubricating layer)
Acrylic monomer (Light acrylate PE-4A manufactured by Kyoeisha Chemical Co., Ltd.)
87.0 parts Acrylic-modified silicone oil (X-22-1602 manufactured by Shin-Etsu Silicone Co., Ltd.)
2.0 parts Silane-coupling-treated silica fine particles 1 5.0 parts Kaolin (ASP-400P, manufactured by Hayashi Kasei Kogyo) 5.0 parts Photopolymerization initiator (Irgacure 184, manufactured by BASF) 1.0 part The composition is as described above. .

<Example 6>
In the thermal transfer sheet 1 prepared in Example 1, the same procedure as in Example 1 was performed, except that the coating liquid-1 for forming a heat-resistant slip layer was replaced with a coating liquid having the following composition to form the heat-resistant slip layer 30. By the procedure, the thermal transfer sheet 1 of Example 6 was obtained. Hereinafter, the coating liquid for forming the heat-resistant lubricating layer 30 of Example 6 is referred to as “coating liquid-6 for forming a heat-resistant lubricating layer”.

(Coating solution-6 for forming heat-resistant lubricating layer)
Acrylic monomer (Light acrylate PE-4A manufactured by Kyoeisha Chemical Co., Ltd.)
87.0 parts Acrylic-modified silicone oil (X-22-1602 manufactured by Shin-Etsu Silicone Co., Ltd.)
2.0 parts Silane-coupled silica fine particles 1 5.0 parts Boehmite (BMM manufactured by Kawai Lime Industry Co., Ltd.) 5.0 parts Photopolymerization initiator (Irgacure 184 manufactured by BASF) 1.0 part The composition is as described above.

<Example 7>
In the thermal transfer sheet 1 prepared in Example 1, the same procedure as in Example 1 was performed, except that the heat-resistant slip layer-forming coating solution-1 was replaced with a coating solution having the following composition to form the heat-resistant slip layer 30. By the procedure, the thermal transfer sheet 1 of Example 7 was obtained. Hereinafter, the coating liquid for forming the heat-resistant lubricating layer 30 of Example 7 is referred to as “coating liquid-7 for forming a heat-resistant lubricating layer”.

(Coating liquid for forming heat-resistant lubricating layer-7)
Acrylic monomer (Light acrylate PE-4A manufactured by Kyoeisha Chemical Co., Ltd.)
87.0 parts Acrylic-modified silicone oil (X-22-1602 manufactured by Shin-Etsu Silicone Co., Ltd.)
2.0 parts Silane-coupled silica fine particles 1 5.0 parts Flat zinc oxide particles (XZ-300F-LP manufactured by Sakai Chemical Industry Co., Ltd.) 5.0 parts Photopolymerization initiator (Irgacure 184 manufactured by BASF) 1.0 The above is the composition.

<Example 8>
In the thermal transfer sheet 1 prepared in Example 1, the same procedure as in Example 1 was performed, except that the coating liquid-1 for forming a heat-resistant slip layer was replaced with a coating liquid having the following composition to form the heat-resistant slip layer 30. By the procedure, the thermal transfer sheet 1 of Example 8 was obtained. Hereinafter, the coating liquid for forming the heat-resistant lubricating layer 30 of Example 8 is referred to as “coating liquid-8 for forming a heat-resistant lubricating layer”.

(Coating solution-8 for forming heat-resistant lubricating layer)
Acrylic monomer (Light acrylate PE-4A manufactured by Kyoeisha Chemical Co., Ltd.)
89.2 parts Acrylic-modified silicone oil (X-22-1602 manufactured by Shin-Etsu Silicone Co., Ltd.)
2.1 parts Silane-coupled silica fine particles 1 2.5 parts Talc (P-6 manufactured by Nippon Talc) 5.1 parts Photopolymerization initiator (Irgacure 184 manufactured by BASF) 1.1 parts The composition is as described above.

<Example 9>
In the thermal transfer sheet 1 prepared in Example 1, the same procedure as in Example 1 was performed, except that the coating liquid-1 for forming a heat-resistant slip layer was replaced with a coating liquid having the following composition to form the heat-resistant slip layer 30. By the procedure, the thermal transfer sheet 1 of Example 9 was obtained. Hereinafter, the coating liquid for forming the heat-resistant lubricating layer 30 of Example 9 is referred to as “coating liquid-9 for forming a heat-resistant lubricating layer”.

(Coating solution-9 for forming heat-resistant lubricating layer)
Acrylic monomer (Light acrylate PE-4A manufactured by Kyoeisha Chemical Co., Ltd.)
89.2 parts Acrylic-modified silicone oil (X-22-1602 manufactured by Shin-Etsu Silicone Co., Ltd.)
2.1 parts Silane-coupled silica fine particles 1 5.1 parts Talc (P-6 manufactured by Nippon Talc) 2.5 parts Photopolymerization initiator (Irgacure 184 manufactured by BASF) 1.1 parts The composition is as described above.

<Example 10>
In the thermal transfer sheet 1 prepared in Example 1, the same procedure as in Example 1 was performed, except that the coating liquid-1 for forming a heat-resistant slip layer was replaced with a coating liquid having the following composition to form the heat-resistant slip layer 30. By the procedure, the thermal transfer sheet 1 of Example 10 was obtained. Hereinafter, the coating liquid for forming the heat-resistant lubricating layer 30 of Example 10 is referred to as “coating liquid for forming a heat-resistant lubricating layer-10”.

(Coating liquid -10 for forming heat-resistant lubricating layer)
Acrylic monomer (Light acrylate PE-4A manufactured by Kyoeisha Chemical Co., Ltd.)
72.5 parts Acrylic-modified silicone oil (X-22-1602 manufactured by Shin-Etsu Silicone Co., Ltd.)
1.7 parts Silane-coupled silica fine particles 1 12.5 parts Talc (P-6 manufactured by Nippon Talc) 12.5 parts Photopolymerization initiator (Irgacure 184 manufactured by BASF) 0.8 part The composition is as described above.

<Comparative Example 1>
In the thermal transfer sheet 1 prepared in Example 1, the same procedure as in Example 1 was performed, except that the coating liquid-1 for forming a heat-resistant slip layer was replaced with a coating liquid having the following composition to form the heat-resistant slip layer 30. By the procedure, a thermal transfer sheet 1 of Comparative Example 1 was obtained. Hereinafter, the coating liquid for forming the heat-resistant lubricating layer 30 of Comparative Example 1 is referred to as “coating liquid-11 for forming a heat-resistant lubricating layer”.

(Coating liquid-11 for forming heat-resistant lubricating layer)
Acrylic monomer (Light acrylate PE-4A manufactured by Kyoeisha Chemical Co., Ltd.)
88.8 parts Silane-coupled silica fine particles 1 5.1 parts Talc (P-6 manufactured by Nippon Talc) 5.1 parts Photopolymerization initiator (Irgacure 184 manufactured by BASF) 1.0 part The composition is as described above.

<Comparative Example 2>
In the thermal transfer sheet 1 prepared in Example 1, the same procedure as in Example 1 was performed, except that the coating liquid-1 for forming a heat-resistant slip layer was replaced with a coating liquid having the following composition to form the heat-resistant slip layer 30. By the procedure, a thermal transfer sheet 1 of Comparative Example 2 was obtained. Hereinafter, the coating liquid for forming the heat-resistant lubricating layer 30 of Comparative Example 2 is referred to as “coating liquid-12 for forming a heat-resistant lubricating layer”.

(Coating solution-12 for forming heat-resistant lubricating layer)
Acrylic monomer (Light acrylate PE-4A manufactured by Kyoeisha Chemical Co., Ltd.)
87.0 parts Non-reactive silicone oil (KF-412 manufactured by Shin-Etsu Silicone Co., Ltd.) 2.0 parts Silane-coupled silica fine particles 1 5.0 parts Talc (P-6 manufactured by Nippon Talc) 5.0 parts Photopolymerization Initiator (Irgacure 184 manufactured by BASF) 1.0 part The composition is as follows.

<Comparative Example 3>
In the thermal transfer sheet 1 prepared in Example 1, the same procedure as in Example 1 was performed, except that the coating liquid-1 for forming a heat-resistant slip layer was replaced with a coating liquid having the following composition to form the heat-resistant slip layer 30. By the procedure, a thermal transfer sheet 1 of Comparative Example 3 was obtained. The coating liquid for forming the heat-resistant lubricating layer 30 of Comparative Example 3 is referred to as “coating liquid for forming a heat-resistant lubricating layer-13”.

(Coating liquid for forming heat-resistant lubricating layer-13)
Acrylic monomer (Light acrylate PE-4A manufactured by Kyoeisha Chemical Co., Ltd.)
87.0 parts Acrylic-modified silicone oil (X-22-1602 manufactured by Shin-Etsu Silicone Co., Ltd.)
2.0 parts Silane-coupled silica fine particles 1 5.0 parts Calcium carbonate (White IGV-IV manufactured by Shiraishi Industry Co., Ltd.) 5.0 parts Photopolymerization initiator (Irgacure 184 manufactured by BASF) 1.0 part .

<Comparative Example 4>
The thermal transfer sheet 1 of Comparative Example 4 was prepared in the same manner as in Example 1 except that the talc added to the coating solution for forming a heat-resistant lubricating layer having the above-mentioned composition was removed from the thermal transfer sheet 1 produced in Example 1. Got. The coating liquid for forming the heat-resistant lubricating layer 30 of Comparative Example 4 is referred to as “coating liquid-14 for forming a heat-resistant lubricating layer”.

(Coating liquid -14 for forming heat-resistant lubricating layer)
Acrylic monomer (Light acrylate PE-4A manufactured by Kyoeisha Chemical Co., Ltd.)
91.5 parts Acrylic-modified silicone oil (X-22-1602 manufactured by Shin-Etsu Silicone Co., Ltd.)
2.1 parts Silane-coupled silica fine particles 1 5.3 parts Photopolymerization initiator (Irgacure 184 manufactured by BASF) 1.1 parts The composition is as described above.

<Comparative Example 5>
In the thermal transfer sheet 1 prepared in Example 1, spherical fine particles added to the heat-resistant lubricating layer forming coating solution having the above composition were treated with a silica fine particle, Sciqas grade 0.05 μm, using a silane coupling agent KBM-5103. A thermal transfer sheet 1 of Comparative Example 5 was obtained in the same procedure as in Example 1, except that the “silane-coupled silica fine particles 1” were replaced with untreated Sciqas grade 0.05 μm. The coating liquid for forming the heat-resistant lubricating layer 30 of Comparative Example 5 is referred to as “coating liquid-15 for forming a heat-resistant lubricating layer”.

(Coating solution-15 for forming heat-resistant lubricating layer)
Acrylic monomer (Light acrylate PE-4A manufactured by Kyoeisha Chemical Co., Ltd.)
87.0 parts Acrylic-modified silicone oil (X-22-1602 manufactured by Shin-Etsu Silicone Co., Ltd.)
2.0 parts silica fine particles (Skaiqas grade 0.05 μm, manufactured by Sakai Chemical Industry Co., Ltd.)
5.0 parts Talc (P-6 manufactured by Nippon Talc) 5.0 parts Photopolymerization initiator (Irgacure 184 manufactured by BASF) 1.0 part The composition is as described above.

<Comparative Example 6>
In the thermal transfer sheet 1 prepared in Example 1, the thermal transfer sheet of Comparative Example 5 was prepared in the same procedure as in Example 1 except that the spherical fine particles added to the coating liquid for forming a heat-resistant lubricating layer having the above composition were removed. 1 was obtained. The coating liquid for forming the heat-resistant lubricating layer 30 of Comparative Example 5 is referred to as “coating liquid-16 for forming a heat-resistant lubricating layer”.

(Coating liquid-16 for forming heat-resistant lubricating layer)
Acrylic monomer (Light acrylate PE-4A manufactured by Kyoeisha Chemical Co., Ltd.)
91.5 parts Acrylic-modified silicone oil (X-22-1602 manufactured by Shin-Etsu Silicone Co., Ltd.)
2.1 parts Talc (P-6 manufactured by Nippon Talc) 5.3 parts Photopolymerization initiator (Irgacure 184 manufactured by BASF) 1.1 parts The composition is as described above.

<Comparative Example 7>
In the thermal transfer sheet 1 prepared in Example 1, spherical fine particles added to the heat-resistant lubricating layer forming coating solution having the above composition were treated with a silica fine particle, Sciqas grade 0.05 μm, using a silane coupling agent KBM-5103. From the “silane-coupled silica fine particles 1”, a silica fine particle of Sakai Chemical Industry Co., Ltd., Sciqas grade 0.4 μm (average particle diameter 0.4 μm) was converted to a silane coupling manufactured by Shin-Etsu Silicone Co., Ltd. having a methacryl group as a functional group. A thermal transfer sheet 1 of Comparative Example 5 was obtained in the same procedure as in Example 1, except that “silane-coupled silica fine particles 3” treated with Agent KBM-5103 in the same manner was used. The coating liquid for forming the heat-resistant lubricating layer 30 of Comparative Example 5 is referred to as “coating liquid for forming a heat-resistant lubricating layer-17”.

(Coating solution for forming heat-resistant lubricating layer-17)
Acrylic monomer (Light acrylate PE-4A manufactured by Kyoeisha Chemical Co., Ltd.)
87.0 parts Acrylic-modified silicone oil (X-22-1602 manufactured by Shin-Etsu Silicone Co., Ltd.)
2.0 parts Silane-coupled silica fine particles 3 5.0 parts Talc (P-6, manufactured by Nippon Talc) 5.0 parts Photopolymerization initiator (Irgacure 184, manufactured by BASF) 1.0 part Table 1 shows materials constituting No. 10 and Comparative Examples 1 to 7.

<Print evaluation>
Using the thermal transfer sheets 1 produced in Examples 1 to 10 and Comparative Examples 1 to 7, black portions (gradation values 255/255: density max) and white The print evaluation of the checkerboard-shaped image pattern of the portion (gradation value 0/255) was performed, and wrinkle evaluation was performed.

<Print conditions>
Printing environment: 23 ° C, 50% RH
Applied voltage: 27V
Printing speed: 10 inch / sec
The results of the print evaluation are shown in Table 2 as "wrinkles".

  In the column of “wrinkles” in Table 2, ○ indicates that there is no wrinkle in the printed matter, Δ indicates that the printed matter has wrinkles, but is small and has no problem, and × indicates that the printed matter is small. Indicates that a large wrinkle that may cause a problem with the object is generated.

<Head cleaning evaluation>
In the thermal transfer sheets produced in Examples 1 to 10 and Comparative Examples 1 to 7, a black portion (gradation value 255/255: density max) and a white portion (gradation value 0/255) were formed by a thermal simulator. The printing of the image pattern was performed for 800 m of the transfer-receiving body, and the state of the stain attached to the thermal head after the printing was visually evaluated using a microscope.

  The printing conditions are the same as the printing evaluation. The results of the evaluation are shown in Table 2 as “head dirt”.

  In the column of “head dirt” in Table 2, ○ indicates that there was no dirt on the head, and good, Δ indicates that there was dirt on the head but there was no problem, and x indicates that there was no problem. Indicates that there is a problem with dirt attached to the surface.

<Bleed-out evaluation>
The thermal transfer sheet 1 produced in each of Examples 1 to 10 and Comparative Examples 1 to 7 was slit into a width of 150 mm and wound around a core having a diameter of 25 mm with a winding tension of 9 g / cm and a length of 300 m. After a lapse of 24 hours at room temperature after the winding, the rolled thermal transfer sheet 1 was stored at 40 ° C. in a 90% RH environment for one week.

  The printed thermal transfer sheet was printed with a thermal simulator, and the presence or absence of density abnormality was visually confirmed.

  The printing conditions are the same as the printing evaluation. The results of the evaluation are shown in Table 2 as “bleed”.

In the column of “bleed” in Table 2, ○ indicates that the printed matter was good without density abnormality, and X indicates that there was a problem with the occurrence of density abnormality. <Dye transfer evaluation>
After the thermal transfer layer 20 is opposed to the thermal transfer sheets prepared in Examples 1 to 10 and Comparative Examples 1 to 7 under a load of 10 kg / cm ² and stored at room temperature for 168 hours, heat resistance is obtained. The absorbance of the slippery layer is measured using a spectrophotometer (UV-3600, manufactured by Shimadzu Corporation), and is compared with the absorbance of a portion not facing the heat-sensitive transfer layer. It was confirmed whether or not the transfer of the dye to the dye had occurred. The results of the evaluation are shown in Table 2 as “dye transfer”.

  In the column of “Dye transfer” in Table 2, ○ indicates that there is no difference in the absorbance between the portion not facing the thermal transfer layer and the portion that does not, and △ indicates that there is a slight difference in absorbance. Indicates that there is no problem, and x indicates that there is a difference in the absorbance and there is a problem.

<Head wear evaluation>
In the thermal transfer sheets produced in Examples 1 to 10 and Comparative Examples 1 to 7, a black portion (gradation value 255/255: density max) and a white portion (gradation value 0/255) were formed by a thermal simulator. The printing of the image pattern was performed for 800 m of the transferred body, and the state of the thermal head after the printing was visually observed using a microscope to confirm whether or not abrasion occurred. The results of the evaluation are shown in Table 2 as "head wear".

  In the column of “Head wear” in Table 2, ○ indicates that the head is not worn and is good, Δ indicates that the head is worn but there is no quality problem, and × indicates the print. This indicates that the head has been worn so as to cause a quality problem. Table 2 shows a list of the evaluation results.

(Evaluation results)
As shown in each evaluation result shown in Table 2, the thermal transfer sheets 1 of Examples 1 to 10 were obtained by setting the binder resin, the lubricant, and the fine particles constituting the heat-resistant lubricating layer to satisfy the conditions described in the above claims. By doing so, it is possible to impart head cleaning properties while preventing wrinkles and breakage during printing, and it is possible to prevent migration of dyes and lubricants during storage and wear of the thermal head.

  The thermal transfer sheet obtained by the embodiment of the present invention can be used for a sublimation transfer type printer, and in addition to the high speed and high function of the printer, various images can be easily formed in full color, so that a digital camera It can be widely used for cards such as self-prints and identification cards, amusement output materials, and the like.

DESCRIPTION OF SYMBOLS 1 Thermal transfer sheet 10 Substrate 20 Thermal transfer layer 30 Heat-resistant lubricating layer 31 Binder 32 Spherical fine particle 33 Flat inorganic fine particle

Claims (4)

At least, a base material, a heat-resistant lubricating layer formed on one surface of the base material, and a heat-sensitive transfer layer formed on the other surface of the base material,
The heat-resistant slip layer,
The binder mainly consists of a reaction product of a reactive silicone oil and a radical polymerization type curable resin,
And containing flat inorganic fine particles and spherical fine particles whose surface is modified by a silane coupling agent,
When the flat inorganic fine particles have a thickness t and a width in a direction perpendicular to the thickness t is a diameter d, the ratio (d _min / t) of the minimum diameter d _min to the thickness t of the diameter d is 2 or more. Some shape,
And a ratio (t / r) of an average thickness t of the flat inorganic fine particles to an average particle diameter r of the spherical fine particles is 1.0 or more.   2. The thermal transfer sheet according to claim 1, wherein the flat inorganic fine particles have a cleavage property such that the flat inorganic fine particles have a cleavage plane that is horizontal to the flat surface of the flat inorganic fine particles. 3.   3. The thermal transfer sheet according to claim 1, wherein the flat inorganic fine particles have a Mohs' hardness of less than 4. The spherical fine particles and the flat inorganic fine particles are each contained in the heat-resistant lubricating layer by 3% or more of the total weight of the heat-resistant lubricating layer,
The thermal transfer sheet according to any one of claims 1 to 3, wherein the total content of the spherical fine particles and the flat inorganic fine particles is 25% or less of the total weight of the heat-resistant lubricating layer.

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