JP6163985B2 - Thermal transfer sheet and method for manufacturing thermal transfer sheet - Google Patents

Description

  The present invention relates to a thermal transfer sheet and a method for manufacturing the thermal transfer sheet.

  As a simple printing method, various thermal transfer recording methods are widely used. In each thermal transfer recording method, a thermal transfer sheet in which a large number of, for example, yellow, magenta, and cyan (black if necessary) color material layers are repeatedly provided in a surface sequence is mainly used on a continuous base material. In the thermal transfer recording method, the color material layer is melted and softened by heating and transferred onto the thermal transfer image-receiving sheet to form an image, and the dye in the color material layer is transferred onto the transferred material by heating. And sublimation recording methods for forming images. Among them, the sublimation recording method uses a sublimation dye as a color material, so it has excellent halftone reproducibility and gradation, and can express a full-color image exactly as it is on the image-receiving sheet. It is applied to color image formation for digital cameras, videos, computers, etc. The image is of a high quality comparable to a silver salt photograph.

  When the thermal transfer sheet is generally stored and used in a wound state, the color material contained in the color material layer exists in a localized state on the surface of the color material layer due to bleeding or the like In this case, the sublimation dye is easily transferred (so-called kick) to the heat-resistant slipping layer side of the thermal transfer sheet. Then, when the sublimation dye transferred to the heat resistant slipping layer side is transferred again to the color material layer side (so-called back), in particular, thermal transfer in which color material layers of different colors are provided in a surface sequential manner. In the sheet, when the sublimation dye transferred to the heat resistant slipping layer side shifts to another color material layer having a hue different from that of the sublimation dye, the color develops during image formation using the other color material layer. Causes deterioration of properties.

  In addition, the color material layer of the thermal transfer sheet is required to be capable of forming a high density image in addition to preventing the occurrence of kick. That is, it is important that the thermal transfer sheet has a color material layer that can form a high density image while preventing the occurrence of kick.

  Under such circumstances, various studies have been made on thermal transfer sheets capable of preventing the occurrence of kicks and forming high-density images. For example, Patent Document 1 discloses a dye layer on one surface of a substrate. In the thermal transfer sheet in which a heat-resistant slipping layer is provided on the other surface of the substrate, an indoaniline dye, a polyvinyl acetal resin A, and a polyvinyl acetal resin B (general in Patent Document 1) A thermal transfer sheet containing a polyvinyl acetal resin represented by the formula (1) has been proposed. According to this thermal transfer sheet, the dye can be prevented from transferring to the heat-resistant slipping layer during storage of the thermal transfer sheet.

  As a method for realizing a high-density image, a method for increasing the ratio of the sublimable dye to the binder resin (a method for increasing the so-called D / B ratio) is known.

  As a thermal transfer sheet capable of preventing the occurrence of kick while allowing high-density image formation, for example, Patent Document 2 has a dye layer containing a resin and a dye on one surface of a base film, and the other In the thermal transfer sheet having a heat-resistant slipping layer containing a lubricant and a resin on the surface, a predetermined dye (a dye represented by the general formula (1) in Patent Document 2) is contained in a predetermined range in the dye layer. Thermal transfer sheets have been proposed. According to this thermal transfer sheet, a high density is obtained and the kick back is remarkably improved.

JP 2009-286060 A JP 2010-83003 A

  However, the various methods known in the art and the patent documents proposed above are not sufficient in the following points, and there is still room for improvement. Specifically, in the method of increasing the D / B ratio, since an excessive sublimable dye is used with respect to the binder resin, the excessive sublimable dye is likely to migrate to the back side of the substrate. Therefore, it is possible to improve the density, but it is difficult to prevent the occurrence of a kick. In addition, when the sublimation dye is in a state of being easily transferred, background stains are easily generated in which an unprinted portion that is not heated from the thermal head is colored by the sublimation dye during image formation. Become.

  Further, in the thermal transfer sheet proposed in Patent Document 1, since the dye species and binder resin species contained in the dye layer are limited to predetermined components, there is a problem that the range of material selection is narrow. To do. Further, there is still room for improvement in terms of forming a high density image. Further, in the thermal transfer sheet proposed in Patent Document 2, since the components of the dye contained in the dye layer and the content thereof are limited, the range of material selection is similarly reduced.

  The present invention has been made in view of such a situation, and it is possible to prevent the occurrence of kicks and background stains while increasing the range of selection of the color material contained in the color material layer, and a high-density image. It is a main subject to provide a thermal transfer sheet capable of forming the above and a manufacturing method of the thermal transfer sheet having this feature.

  The present invention for solving the above-described problems is a thermal transfer sheet in which a color material layer is provided on one surface of a substrate, and the color material layer is soluble in a predetermined solvent and the predetermined solvent. It contains a sublimable dye and a colorant dispersible in the predetermined solvent.

  Further, the present invention for solving the above problems is a thermal transfer sheet in which a color material layer is provided on one surface of a base material, and the color material layer is a first color material from the base material side. The first color material layer contains a first solvent and a sublimable dye that is soluble in the first solvent. The second color material layer contains a second solvent and a color material dispersible in the second solvent.

  Further, the present invention for solving the above problems is a method for producing a thermal transfer sheet, comprising a step of coating a color material layer coating liquid on a substrate to form a color material layer, As the color material layer coating liquid, a coating liquid containing a predetermined solvent, a sublimable dye that can be dissolved in the predetermined solvent, and a color material that can be dispersed in the predetermined solvent is used. .

  Moreover, in the manufacturing method of a thermal transfer sheet, the coating liquid may further contain a dispersant.

  Moreover, this invention for solving the said subject apply | coats the coating liquid containing the sublimable dye which can be melt | dissolved in the said 1st solvent and the said 1st solvent on a base material, 1st A step of forming a color material layer, and a second solvent and a coating liquid containing a color material dispersible in the second solvent are coated on the first color material layer, And a step of forming a color material layer.

  According to the thermal transfer sheet of the present invention, it is possible to prevent the occurrence of kicks and background stains and to form a high-density image without being particularly restricted by the dye contained in the color material layer. Further, according to the method for producing a thermal transfer sheet of the present invention, it is possible to produce a thermal transfer sheet having the above characteristics without being particularly restricted by the dye contained in the color material layer.

It is a schematic sectional drawing which shows an example of the thermal transfer sheet of 1st Embodiment of this invention. It is a schematic sectional drawing which shows an example of the thermal transfer sheet of 2nd Embodiment of this invention. It is a schematic sectional drawing which shows an example of the thermal transfer sheet manufactured by the comparative manufacturing method. It is a schematic sectional drawing which shows an example of the thermal transfer sheet manufactured by the comparative manufacturing method. It is a schematic sectional drawing which shows an example of the thermal transfer sheet manufactured by the manufacturing method of 1st Embodiment of this invention. It is a schematic sectional drawing which shows an example of the thermal transfer sheet manufactured by the manufacturing method of 2nd Embodiment of this invention.

<< Method for producing thermal transfer sheet >>
Hereinafter, the manufacturing method of the thermal transfer sheet of the present invention will be specifically described focusing on the manufacturing method of the thermal transfer sheet of the first embodiment and the manufacturing method of the thermal transfer sheet of the second embodiment. Hereinafter, the manufacturing method of the first embodiment may be simply referred to as the manufacturing method of the second embodiment.

<The manufacturing method of the thermal transfer sheet of 1st Embodiment>
Hereinafter, the superiority of the thermal transfer sheet manufactured by the manufacturing method of the first embodiment will be described with reference to FIGS. 3 and 4 are schematic cross-sectional views of a thermal transfer sheet manufactured by a comparative manufacturing method that does not satisfy the invention-specific matters of the manufacturing method of the present embodiment. Specifically, FIG. 3 is a schematic cross-sectional view of a thermal transfer sheet 100A in which a color material layer 2A is provided on one surface of the substrate 1, and the color material layer 2A can be dissolved in a predetermined solvent. The sublimable dye 10x is formed using a coating solution in which the predetermined solvent is dissolved. FIG. 4 is a schematic cross-sectional view of the thermal transfer sheet 100B in which the color material layer 2B is provided on one surface of the base material. The color material layer 2B contains the color material 10y dispersible in a predetermined solvent. It is formed using a coating liquid dispersed in a predetermined solvent.

  FIG. 5 is a schematic cross-sectional view of a thermal transfer sheet manufactured by the manufacturing method of the first embodiment. In the manufacturing method of the first embodiment, a coating material for a color material layer including a predetermined solvent, a sublimable dye that can be dissolved in the predetermined solvent, and a color material that can be dispersed in the predetermined solvent is used. A color material layer 2 is formed on the substrate 1. In other words, the color material layer 2 is formed on the substrate 1 using the color material layer coating solution in which the sublimable dye 10x is dissolved in the predetermined solvent and the color material 10y is dispersed in the predetermined solvent. Is formed. In each figure, the sublimation dye 10x and the color material 10y are exaggerated.

  The density of the image formed by the thermal transfer recording method is considered to be closely related to the heat transferability of the sublimation dye contained in the color material layer. In order to achieve this, it is important to improve the heat transfer property of the sublimable dye contained in the color material layer. Examples of a method for improving the heat transfer property of the sublimable dye include a method of forming a color material layer using a coating solution in which a sublimable dye is dissolved in a solvent. According to the color material layer formed by this method, the sublimable dye can be present at the molecular level in the color material layer, and the heat transfer property of the sublimable dye in the color material layer can be improved. . In addition, in a color material layer formed using a coating liquid in which a sublimable dye is dispersed in a solvent instead of a coating liquid in which a sublimable dye is dissolved in a solvent, the color material layer includes a sublimation property. Since the dye exists in a state having a certain particle diameter, the heat transfer property of the sublimable dye is lowered, and it is difficult to form an image having a high density.

  By the way, a sublimable dye that can be dissolved in a solvent usually has a low molecular weight and is a single molecule. Therefore, in a color material layer formed using a coating liquid in which a sublimable dye is dissolved in a solvent, As shown in FIG. 3, the sublimable dye 10x exists in a localized state at the interface of the color material layer 2A. The thermal transfer sheet is generally stored in a small roll state, and in the small roll state, the color material layer and the heat-resistant slipping layer are in direct contact with each other, so that the sublimable dye 10x is contained in the color material layer 2A. When present in the state shown in FIG. 3, the sublimable dye 10 x easily moves to the heat-resistant slipping layer 5 side of the substrate 1 when the thermal transfer sheet is stored in a small roll state. That is, when the color material layer 2A is simply formed using a coating solution in which the sublimable dye 10x is dissolved in a predetermined solvent, it is possible to form a high density image with improved heat transfer. It is excellent in terms, but it cannot prevent kicks and dirt.

  On the other hand, by using a sublimation dye having a high molecular weight, even if the localization to the interface of the sublimable dye can be reduced, the affinity between the binder having a high molecular weight and the binder is insufficient. It becomes difficult to prevent the occurrence of kicks and dirt. In other words, a sublimation dye having a high molecular weight is preferable in terms of preventing localization of the sublimation dye at the interface, and a sublimation dye having a high affinity with the binder in terms of preventing the occurrence of kicks and dirt. However, sublimable dyes that satisfy both requirements are limited, and the range of material selection is limited.

  In order to prevent localization of sublimation dyes at the interface, which can cause kicks and soiling, the color material layer should be formed using a coating solution in which the color material is dispersed in a solvent. Is preferred. In the color material layer 2B formed using a coating liquid in which a color material is dispersed in a solvent, as shown in FIG. 4, the color material 10y is present in a state of being uniformly dispersed in the color material layer 2B. It is possible to prevent the occurrence of kicks and soiling that can be caused by the sublimation dye being localized at the interface. In addition, the color material 10y said by this-application specification is the concept containing a sublimation dye and a pigment.

  However, in the color material layer 2B formed using the coating liquid in which the color material is dispersed in the solvent, the color material 10y exists in a state having a constant particle diameter. Therefore, in this case, the heat transferability of the color material is low, and in terms of concentration compared to a color material layer (see FIG. 3) formed using a coating liquid in which a sublimable dye is dissolved in a solvent. Inferior. In other words, the color material layer 2B formed using a coating liquid in which a color material is dispersed in a solvent is excellent in that it can prevent the occurrence of kicks and background stains, but can form a high-density image. Can not.

  Therefore, in the method for manufacturing a thermal transfer sheet according to the first embodiment, a color material for forming a color material layer includes a step of forming a color material layer by applying a color material layer coating liquid on a substrate. As the layer coating solution, a coating solution containing a predetermined solvent, a sublimable dye that can be dissolved in the predetermined solvent, and a colorant that can be dispersed in the predetermined solvent is used. That is, the color material layer is formed using a color material layer coating solution in which a sublimable dye is dissolved and a color material is dispersed in a predetermined solvent. According to the manufacturing method of the thermal transfer sheet of the first embodiment having this feature, it is possible to manufacture a thermal transfer sheet capable of forming a high-density image while preventing the occurrence of kicks and scumming. In the present specification, a color material that can be dispersed in a predetermined solvent means a color material that cannot be dissolved in the predetermined solvent.

"Method for identifying the solubility and dispersibility of coloring materials (sublimation dyes) in a given solvent"
Whether or not the target color material for inclusion in the coating solution can be dissolved in a predetermined solvent can be determined by the following method. A target color material is added to a predetermined solvent so as to have an amount of 2 w / v%, and the mixture is heated and stirred at 50 ° C. for 1 hour. Next, after the obtained liquid is allowed to stand at 25 ° C. for 60 hours, the presence or absence of precipitation of the target color material is visually confirmed. At this time, when the deposition of the target color material cannot be visually confirmed, it can be determined that the target color material is a color material that can be dissolved in a predetermined solvent. On the other hand, when the deposition of the target color material can be confirmed visually, it can be determined that the target color material is a color material that cannot be dissolved in a predetermined solvent, in other words, can be dispersed. Sublimation dyes can also be determined by the same method.

  Although the detailed mechanism by which the thermal transfer sheet manufactured by the manufacturing method of the first embodiment exhibits the above effects is not necessarily clear at present, in the color material layer 2 formed by the manufacturing method of the present embodiment, It is presumed that localization of the sublimation dye 10x at the interface is suppressed, thereby preventing the occurrence of kicks and soiling. Specifically, the color material 10y dispersed in the color material layer coating liquid functions as a role of suppressing the localization of the sublimable dye 10x to the interface of the color material layer 2, and in the present embodiment. It is presumed that the sublimable dye 10x can be dispersed in the color material layer 2 formed by the manufacturing method.

  The reason why the color material 10y dispersed in the color material layer coating solution functions as a role of suppressing localization to the interface of the sublimable dye 10x dissolved in the color material layer coating solution. The affinity between the sublimable dye 10x and the color material 10y can be given. Conventionally, when the color material layer is formed using the sublimable dye 10x dissolved in the color material layer coating solution, as shown in FIG. Localize towards. However, in the manufacturing method of the first embodiment, since the color material 10y is dispersed in the color material layer coating liquid, the affinity of the color material 10y and the sublimation dye 10x causes In the color material layer 2 formed by the manufacturing method, it is speculated that the sublimable dye 10x can be present around the color material 10y existing in a dispersed state. As a result, as shown in FIG. 5, in the color material layer 2 formed by the manufacturing method of the present embodiment, the localization of the sublimation dye 10x to the interface is suppressed, and the sublimation dye 10x is changed to the color material layer 2. It is possible to exist in a dispersed state, and it is considered that the occurrence of kicks and dirt is prevented.

  In addition, since the color material layer 2 is formed using a color material layer coating solution in which a sublimation dye is dissolved in a solvent, the sublimation dye can be present in the color material layer 2 at a molecular level. In addition, it is possible to form a high-density image while preventing the occurrence of kicks and dirt.

  Even if not based on this presumed mechanism, the color material layer 2 is formed by using a coating liquid in which the sublimable dye 10x is dissolved in a predetermined solvent and the color material 10y is dispersed in the predetermined solvent. It is clear from the results of Examples and Comparative Examples that will be described later that it is possible to prevent the occurrence of kicks and dirt and to form images with high density.

  Hereinafter, each component used in the manufacturing method of 1st Embodiment and each component contained in the coating material for color material layers are demonstrated.

(Base material)
The substrate 1 is not particularly limited as long as it has a certain degree of heat resistance and strength, and a conventionally known material can be appropriately selected and used. As such a substrate 1, for example, a polyethylene terephthalate film, a 1,4-polycyclohexylenedimethylene terephthalate film, a polyethylene naphthalate film, a polyphenylene sulfide having a thickness of about 0.5 μm to 50 μm, preferably about 1 μm to 10 μm. Film, polystyrene film, polypropylene film, polysulfone film, aramid film, polycarbonate film, polyvinyl alcohol film, cellophane, cellulose derivatives such as cellulose acetate, polyethylene film, polyvinyl chloride film, nylon film, polyimide film, ionomer film, etc. . Furthermore, each of these materials can be used alone, but may be used as a laminate in combination with other materials.

  In addition, the base material 1 may be subjected to an adhesion treatment on the surface on which the color material layer 2 is formed. By performing the adhesion treatment, adhesion between the base material 1 and the color material layer 2 or an arbitrary layer provided between the base material 1 and the color material layer 2 can be improved.

  Examples of the adhesion treatment include known resin surfaces such as corona discharge treatment, flame treatment, ozone treatment, ultraviolet treatment, radiation treatment, surface roughening treatment, chemical treatment, plasma treatment, low temperature plasma treatment, primer treatment, and grafting treatment. The reforming technique can be applied as it is. Two or more of these treatments can be used in combination.

(Coloring material layer coating solution)
The color material layer coating liquid includes a binder resin, a predetermined solvent, a sublimable dye that can be dissolved in the predetermined solvent, and a color material that can be dispersed in the predetermined solvent. That is, in the color material layer coating liquid, the sublimable dye 10x exists in a dissolved state, and the color material 10y exists in a dispersed state.

"Binder resin"
Examples of the binder resin contained in the color material layer coating liquid include, for example, ethyl cellulose resins, hydroxyethyl cellulose resins, ethyl hydroxy cellulose resins, methyl cellulose resins, cellulose acetate resins, cellulose resins such as nitrocellulose resins, polyvinyl alcohol resins, Polyvinyl acetate resin, polyvinyl butyral resin, polyvinyl acetal resin, vinyl resins such as polyvinyl pyrrolidone, acrylic resins such as poly (meth) acrylate and poly (meth) acrylamide, polyurethane resins, polyamide resins, polyester resins, etc. Is mentioned. Among these, cellulose-based, vinyl-based, acrylic-based, polyurethane-based, and polyester-based resins are preferable in terms of heat resistance, color material heat transferability, and the like. Binder resin may be used individually by 1 type, and 2 or more types can also be mixed and used for it.

"Predetermined solvent"
The predetermined solvent contained in the color material layer coating liquid means a solvent capable of dissolving a sublimable dye described later and dispersing the color material. That is, the predetermined solvent is not particularly limited and can be appropriately selected according to the relationship between the sublimable dye and the color material. Examples of the solvent include organic solvents such as methyl ethyl ketone, toluene, xylene, methyl isobutyl ketone, ethyl acetate, isopropyl alcohol, and ethanol, and water.

  The solvent contained in the color material layer coating solution may be used alone or in combination of two or more. For example, a solvent A that can dissolve a sublimable dye and a solvent B that can disperse a coloring material can be used in combination. In addition, when using the said solvent A and the solvent B, the solvent A which can melt | dissolve a sublimable dye is on condition that a coloring material cannot be melt | dissolved. Since the sublimable dye is dissolved by the solvent A, the solvent B may be a solvent that can dissolve the sublimable dye as long as it satisfies the condition that the coloring material can be dispersed. It may be a solvent that cannot dissolve the sublimable dye. The color material layer coating solution may further contain a solvent other than the solvent A and the solvent B, but at least one color material contained in the color material layer coating solution is: The colorant layer coating solution is insoluble in all solvents.

"Sublimation dyes that can be dissolved in a given solvent"
There is no particular limitation on the sublimable dye that can be dissolved in the predetermined solvent, and the dye can be appropriately selected according to the type of the predetermined solvent contained in the coating liquid for forming the color material layer. Specifically, any sublimation dye may be used as long as it is a sublimation dye that can be dissolved in a solvent contained in the coating liquid.

"Coloring material that can be dispersed in a given solvent"
The color material that can be dispersed in the predetermined solvent is not particularly limited, and can be appropriately selected according to the type of the predetermined solvent contained in the coating liquid for forming the color material layer. Specifically, any color material may be used as long as the color material can be dispersed in the solvent contained in the coating liquid. Here, the dispersible color material means a color material that cannot be dissolved in a predetermined solvent, and the dispersibility of the color material is not particularly limited. For example, a dispersing agent can be used to improve the dispersion performance of the color material. That is, as a result, the color material may be dispersed in the color material layer coating solution.

  Examples of the sublimable dye that can be dissolved in the predetermined solvent and the colorant that can be dispersed in the predetermined solvent include, among the sublimable dyes exemplified below, as appropriate depending on the solvent contained in the coating liquid. You can choose. Specifically, a predetermined solvent is selected, and then, among the sublimable dyes exemplified below, a sublimable dye that can be dissolved in the predetermined solvent and a colorant that can be dispersed in the predetermined solvent. A sublimable dye may be selected.

  Examples of sublimation dyes include diarylmethane dyes, triarylmethane dyes, thiazole dyes, merocyanine dyes, pyrazolone dyes, pyrazolone methines, pyridone methine and other methine dyes, indoaniline dyes, indonaphthol dyes, Acetophenone azomethine, pyrazoloazomethine, pyrazolone azomethine, pyrazolotriazole azomethine, imidazoline dye such as imidazolazomethine, imidazoazomethine, pyridone azomethine, xanthene dye, oxazine dye, cyanostyrene dye such as dicyanostyrene, tricyanostyrene , Thiazine dyes, azine dyes, acridine dyes, benzeneazo dyes, pyridone azo, thiophenazo, thiazole azo, isothiazole azo, pyrrole azo, pyrazo Azo dyes such as azo, imidazole azo, thiadiazole azo, triazole azo, and disazo, spiropyran dyes, indolinospiropyran dyes, fluorane dyes, rhodamine lactam dyes, naphthoquinone dyes, anthraquinone dyes, quinophthalone dyes, amino Examples include pyrazole dyes, pyrazolotriazole dyes, styryl dyes such as dicyanostyryl and tricyanostyryl.

  Specifically, C.I. I. (Color index) Disperse Yellow 51, 3, 54, 79, 60, 23, 7, 141, 201, 231, C.I. I. Disperse blue 24, 56, 14, 301, 334, 165, 19, 72, 87, 287, 154, 26, 354, C.I. I. Disper thread 135,146,59,1,73,60,167, C.I. I. Disperse Orange 149, C.I. I. Disperse violet 4, 13, 26, 36, 56, 31, C.I. I. Solvent Yellow 56, 14, 16, 29, 93, C.I. I. Solvent Blue 70, 35, 63, 36, 50, 49, 111, 105, 97, 11, C.I. I. Solvent Red 135, 81, 18, 25, 19, 23, 24, 143, 146, 182, C.I. I. Solvent Violet 13, C.I. I. Solvent Black 3, C.I. I. Solvent Green 3 etc. can be mentioned.

  Among them, the quinophthalone dye represented by the following general formula (1) is a sublimable dye that is soluble in a predetermined solvent or dispersible in a predetermined solvent in that it has light resistance and high brightness. It can be preferably used.

X in the general formula (1) represents a hydrogen atom or a halogen atom, and R ¹ represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a derivative thereof, an alkyl group, or a total carbon number of 6 to 6 including a benzene ring. 10 acyl groups are represented. In general formula (1), the quinophthalone dye in which X and R ¹ are both hydrogen atoms is Disperse Yellow 54. Further, in the general formula (1), the quinophthalone dye in which X is Br and R ¹ is a hydrogen atom is Disperse Yellow 64.

  Commercially available sublimation dyes can be used as they are. For example, yellow dyes such as Foron Brilliant Yellow S-6GL (Sand Corp., Disperse Yellow 231), Macrolex Yellow 6G (Bayer Corp., Disperse Yellow 201), magenta MS-RED-G (manufactured by Mitsui Toatsu Chemical Co., Ltd., Disperse Red 60), Macrolex Red Violet R (manufactured by Bayer, Disperse Violet 26), cyan dye is Kayaset Blue 714 (Nippon Kayaku Co., Ltd.) Manufactured by Solvent Blue 63), Foron Brilliant Blue S-R (Sand Corp., Disperse Blue 354), Waxolin Blue AP-FW (ICI, Solvent Blue 36), and the like.

  Sublimation dyes that can be dissolved in a predetermined solvent may be used alone or in combination of two or more. Moreover, when the colorant dispersible in a predetermined solvent is a sublimable dye, the dispersible sublimable dye may be used alone or in combination of two or more. You can also. Further, as a colorant dispersible in a predetermined solvent, a sublimable dye and a pigment can be used in combination. Two or more pigments can be used in combination.

  When a pigment is used as a colorant dispersible in a predetermined solvent, it may be appropriately selected from known organic or inorganic pigments or dyes. The pigment preferably has a sufficient color density and does not discolor or fade due to light, heat, or the like. The color of the pigment is not limited to cyan, magenta, yellow, and black, and various colorants can be used.

  Examples of pigments include azo pigments, phthalocyanine pigments, quinacridone pigments, perylene / perinone pigments, isoindolinone pigments, isoindoline pigments, dioxazine pigments, quinophthalone pigments, diketopyrrolopyrrole pigments, Anthraquinone pigments, thioindigo pigments, metal complex pigments and the like can be mentioned. Among these organic pigments, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 150, C.I. I. Pigment green 7, C.I. I. Pigment green 36, C.I. I. Pigment red 122 and C.I. I. Pigment Violet 19 and the like are preferable because of high luminance. In addition, the pigment represented by the following general formula (2) has high dispersibility in the coating material for the color material layer, can improve the stability of the coating solution for the color material layer, It can be preferably used as a colorant that can be dispersed in a predetermined solvent in that the occurrence of contamination can be more effectively prevented.

R ^{1 to} R ⁵ in the general formula (2) are a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a derivative thereof, a sulfonic acid group (—SO ₃ H), or a sulfonation inducing group substituted with a sulfonamide group. Represents.

In a preferred form of the pigment represented by the general formula (2), R ^{1 to} R ⁵ have a sulfonation inducing group substituted with at least one sulfonic acid group (—SO ₃ H) or a sulfonamide group. Furthermore, a part or all of the sulfonic acid group may be salted with an amine, ammonium hydroxide, chloride, bromide or the like, or a metal to form a sulfonate.

  Hereinafter, a specific solvent will be described as an example, and an example of a sublimable dye contained in a coating liquid for forming the color material layer 2 and an example of the color material will be described. Note that the present invention is not limited to this combination.

When the predetermined solvent is a mixed solvent of methyl ethyl ketone / toluene;
As a sublimable dye that can be dissolved in a mixed solvent of methyl ethyl ketone / toluene, for example, Disperse Yellow 201 can be used. Examples of the colorant that can be dispersed in a mixed solvent of methyl ethyl ketone / toluene include the pigments exemplified above and the sublimation dyes exemplified above such as Disperse Yellow 54.

  Further, the color material layer coating solution may contain a dispersant for improving the dispersibility of the color material. Examples of the dispersant include a graft type polymer dispersion aid, a polyether type dispersion aid, and an acrylic block type polymer dispersant. In addition to this, examples of the dispersant include derivatives obtained by treating an organic pigment with a sulfonated product and the like. Examples of the treatment method include rosin treatment, surface treatment methods such as acidic group treatment, basic treatment, and pigment derivative treatment.

  In addition, in the coating liquid for the color material layer, together with a binder resin that is an essential component, a predetermined solvent, a sublimable dye that can be dissolved in the predetermined solvent, and a color material that can be dispersed in the predetermined solvent, Includes other optional components such as release agents for improving releasability from the receiving layer of the thermal transfer image-receiving sheet, antistatic agents, organic or inorganic fillers for controlling the slipperiness with the receiving layer, etc. It may be.

Although there is no limitation in particular about the formation method of the color material layer 2, a binder resin, a solvent, a sublimation dye soluble in the solvent, a color material dispersible in the solvent, a dispersant, a release agent, and the like as necessary. Using an arbitrary component to be added, a sublimable dye is dissolved in a solvent, and a color material layer coating liquid in which a color material is dispersed is prepared, and the color material layer coating liquid is obtained by a gravure printing method. It can be formed by coating and drying on a substrate using a known means such as a screen printing method or a reverse roll coating method using a gravure plate. Although there is no particular limitation on the coating amount of the colorant layer coating solution is preferably 0.2g / m ² ~10g / m ² approximately in solids.

  As described above, the manufacturing method according to the first embodiment has been described mainly on the manufacturing method in which the color material layer 2 is directly provided on the base material 1. The step of providing the layer may be included. Moreover, the process of providing arbitrary layers in the surface of the side which does not form the color material layer 2 of the base material 1 may be included. For example, a step of providing a dye primer layer between the base material 1 and the color material layer 2 and a step of providing a heat-resistant slipping layer on the other surface side of the base material 1 may be included.

<The manufacturing method of the thermal transfer sheet of 2nd Embodiment>
Next, the thermal transfer sheet manufactured by the thermal transfer sheet manufacturing method of the second embodiment will be described with reference to FIG. FIG. 6 is a schematic cross-sectional view of a thermal transfer sheet manufactured by the thermal transfer sheet manufacturing method of the second embodiment.

  In the method for producing a thermal transfer sheet of the second embodiment, a first color is applied on a base material by applying a coating liquid containing a first solvent and a sublimable dye soluble in the first solvent. A step of forming a material layer; and a second colorant, wherein a second solvent and a coating liquid containing a colorant dispersible in the second solvent are applied on the first colorant layer, And a step of forming a layer.

  In the present embodiment, a first color material layer 2C is formed on a base material by applying a coating liquid containing a first solvent and a sublimable dye that can be dissolved in the first solvent. As explained above, in the color material layer formed using the coating liquid in which the sublimation dye is dissolved, the sublimation dye is present in a localized state at the interface (see FIG. 3). Kicks and dirt are likely to occur. That is, when a thermal transfer sheet in which only the first color material layer 2C is provided on the substrate 1, an image having a high density can be formed using the manufactured thermal transfer sheet. However, it cannot prevent kicks and dirt.

  Thus, in the present embodiment, the occurrence of kicks or background stains that cannot be compensated for by the first color material layer 2C is prevented by forming another layer on the first color material layer 2C. Specifically, in the present embodiment, a second solvent and a coating liquid containing a color material dispersible in the second solvent are applied onto the first color material layer 2C, and the second color is applied. A color material layer is formed. Since the second color material layer 2D formed in the present embodiment is formed using a coating liquid in which the color material is dispersed, the color material 10y is formed in the formed second color material layer 2D. It is uniformly dispersed (see FIG. 4), and the presence of the second color material layer 2D can prevent the occurrence of kicks and dirt. That is, the second color material layer 2D mainly serves as a lid that blocks the sublimable dye 10x localized at the interface of the first color material layer 2C.

  Further, since the first color material layer 2C is formed between the base material 1 and the second color material layer 2D using the coating liquid in which the sublimation dye is dissolved, the first color material layer 2C is formed. In the color material layer 2C, the sublimable dye 10x can be present at the molecular level. Thereby, the heat transfer property of the sublimable dye contained in the first color material layer 2C can be improved, and an image having a high density can be formed. In addition, since the second color material layer 2D includes the color material 10y, a higher density image can be formed by the synergistic effect of the sublimable dye 10x and the color material 10y.

  Hereinafter, the coating liquid used for forming the first color material layer 2C and the second color material layer 2D will be described. Hereinafter, the coating liquid used for forming the first color material layer 2C is referred to as “first coating liquid”, and the coating liquid used for forming the second color material layer 2D is referred to as “second coating liquid”. Will be described.

(First coating solution)
The first coating liquid contains a binder resin, a first solvent, and a sublimable dye that can be dissolved in the first solvent. That is, the sublimable dye is present in a dissolved state in the first coating liquid.

  There is no limitation in particular about binder resin contained in a 1st coating liquid, According to the kind of sublimation dye which can be melt | dissolved in a 1st solvent, it can select suitably. For example, the binder resin contained in the coating liquid for color material layers demonstrated with the manufacturing method of the said 1st Embodiment can be mentioned. The same applies to the binder resin contained in the second coating liquid described below.

"Sublimation dye"
There is no limitation in particular about the sublimation dye melt | dissolved in a 1st coating liquid, According to the 1st solvent contained in the said 1st coating liquid, it can select suitably. As a sublimation dye, the sublimation dye demonstrated with the manufacturing method of 1st Embodiment can be mentioned, for example. Two or more types of sublimable dyes may be contained in the first coating liquid.

"First solvent"
The first solvent is not particularly limited as long as it can dissolve the sublimable dye, and can be appropriately selected from conventionally known solvents. The first coating liquid may contain two or more solvents, but at least one solvent can dissolve at least one sublimable dye contained in the first coating liquid. It must be a solvent.

  The first coating liquid may contain a color material that can be dispersed in the first solvent. That is, the first color material layer 2C may have the same configuration as the color material layer 2 (see FIG. 5) formed by the manufacturing method of the first embodiment. Moreover, in the 1st coating liquid, arbitrary components may contain besides the said binder resin, a 1st solvent, and a sublimation dye.

Although there is no limitation in particular about the formation method of the 1st color material layer, the 1st coating liquid which dissolved the sublimation dye in the solvent is prepared, The gravure printing method and the screen printing method are used for the said 1st coating liquid. It can be formed by coating and drying on a substrate using a known means such as a reverse roll coating method using a gravure plate. Although there is no particular limitation on the coating amount of the first coating liquid is preferably 0.1g / m ² ~5g / m ² approximately in solids.

(Second coating liquid)
The second coating liquid contains a binder resin, a second solvent, and a color material that can be dispersed in the second solvent. That is, the color material exists in a state dispersed in the second coating liquid.

"Coloring material"
There is no limitation in particular about the coloring material melt | dissolved in a 2nd coating liquid, According to the 2nd solvent contained in the said 2nd coating liquid, it can select suitably. The coloring material may be a sublimation dye or a pigment, and the coloring material described in the manufacturing method of the first embodiment can be used. Further, two or more kinds of color materials may be contained in the second coating liquid.

"Second solvent"
The second solvent is not particularly limited as long as it can disperse the coloring material, and can be appropriately selected from conventionally known solvents. The second coating liquid may contain two or more solvents, but at least one coloring material contained in the second coating liquid cannot be dissolved in all the two or more solvents. On condition that

  Moreover, in the 2nd coating liquid, arbitrary components may contain besides the said binder resin, a 2nd solvent, and a sublimation dye. For example, the second coating liquid may contain a dispersant for improving the dispersibility of the color material. As the dispersant, for example, the dispersant described in the first embodiment can be used.

  Further, the second coating liquid may contain a sublimable dye that is soluble in the second solvent contained in the second coating liquid. That is, the second color material layer 2D may have the same configuration as the color material layer 2 (see FIG. 5) formed by the manufacturing method of the first embodiment. According to this configuration, since the sublimation dye is dissolved in both the first coating liquid and the second coating liquid, the first color material layer 2C, the second color material. Due to the synergistic effect with the layer 2D, an image with a higher density can be formed.

  When the second color material layer 2D formed using the second coating liquid is located on the outermost surface of the thermal transfer sheet, a release agent is included in the second coating liquid. It is preferable. As a mold release agent, the mold release agent etc. which were demonstrated with the manufacturing method of 1st Embodiment can be used. In addition, when a measure for improving the releasability from the color material layer 2D is taken on the receiving material side, for example, the receiving layer side of the thermal transfer image receiving sheet, a release agent is included in the second coating liquid. It is not necessary to make it.

  As described above, in the manufacturing method of the second embodiment, the first solvent contained in the first coating liquid, the sublimable dye that is soluble in the first solvent, and the second solvent contained in the second coating liquid. However, the first solvent, the second solvent, and the sublimation dye contained in the first coating liquid and the second coating liquid are described. Different color materials may be used. In addition, a common solvent may be used as the first solvent and the second solvent, and different dyes may be used as the sublimable dye contained in the first coating liquid and the color material contained in the second coating liquid. . In this case, the at least one sublimation dye contained in the first coating liquid only needs to be soluble in a common solvent, and at least one color material contained in the second coating liquid is common. What is necessary is just to be dispersible with respect to a solvent.

  Further, a sublimable dye contained in the first coating liquid and a color material common as the color material contained in the second coating liquid may be used, and different solvents may be used as the first solvent and the second solvent. . In this case, the first solvent contained in the first coating liquid only needs to be able to dissolve the common coloring material, and the second solvent contained in the second coating liquid and different from the first solvent is Any common colorant can be dispersed.

Although there is no limitation in particular about the formation method of a 2nd coloring material layer, the 2nd coating liquid which disperse | distributed the coloring material in the solvent is prepared, The said 2nd coating liquid is a gravure printing method, a screen printing method, It can be formed by coating and drying on the first color material layer using a known means such as a reverse roll coating method using a gravure plate. Although there is no particular limitation on the coating amount of the second coating liquid is preferably 0.1 g / m ² to 5 g / m ² approximately in solids.

  As described above, the manufacturing method according to the second embodiment has been described focusing on the manufacturing method in which the second color material layer 2D is directly provided on the first color material layer 2C. However, the first color material layer 2C has been described. And a step of providing an arbitrary layer between the second color material layer 2D. Moreover, the process of providing arbitrary layers between the base material 1 and the 1st color material layer 2C may be included. Moreover, the process of providing arbitrary layers in the surface of the side which does not form 2C of 1st color material layers of the base material 1 may be included.

  Next, the thermal transfer sheet of the present invention will be described in the first embodiment and the second embodiment.

<Thermal transfer sheet of the first embodiment>
The thermal transfer sheet 100 of 1st Embodiment takes the structure by which the color material layer 2 was provided on the base material 1, as shown in FIG. Here, in the thermal transfer sheet 100 of the first embodiment, the color material layer 2 contains a predetermined solvent, a sublimation dye, and a color material, and the sublimation dye can be dissolved in the predetermined solvent. A sublimable dye, and the colorant is a colorant dispersible in a predetermined solvent.

  According to the thermal transfer sheet of the first embodiment provided with the color material layer 2 having the above-described characteristics, it is possible to prevent the occurrence of kicks and background stains for the reason described in the manufacturing method of the first embodiment, and the image has high density. Can be formed.

  In this embodiment, the predetermined solvent contained in the color material layer 2 is an essential component, but this is intended to positively contain the predetermined solvent in the color material layer 2. The predetermined solvent contained in the color material layer 2 does not mean a residual solvent contained in the color material layer 2. Specifically, when the solvent remaining in the color material layer is a solvent that can dissolve the sublimable dye contained in the color material layer and is a solvent that can disperse the color material, It can be said that the same effects as the thermal transfer sheet manufactured by the manufacturing method of the first embodiment can be obtained.

"Identification method of colorant components and residual solvent"
Whether or not the target thermal transfer sheet (hereinafter referred to as the target thermal transfer sheet) satisfies the invention-specific matters of the thermal transfer sheet of the present embodiment can be determined, for example, by the following method. First, the color material layer of the target thermal transfer sheet is analyzed to identify the color material component contained in the color material layer. The color material component can be identified using a conventionally known analysis method such as nuclear magnetic resonance spectroscopy or IR spectroscopy.

  In the analysis of the color material layer, when only one color material component is included in the color material layer, it can be determined that the target thermal transfer sheet does not satisfy the invention-specific matters of the thermal transfer sheet of the present embodiment. . On the other hand, when two or more kinds of color material components are specified in the color material layer of the target thermal transfer sheet, the type of the solvent remaining in the color material layer is then specified. As a method for specifying the type of solvent, for example, it can be specified using a gas chromatography method. For example, a gas chromatography GC14-A manufactured by Shimadzu Corporation can be used to specify the type of solvent by gas chromatography. In addition, in order to exclude the solvent contained in the base material of the target thermal transfer sheet, the heat-resistant slipping layer, or an arbitrary layer, the layer corresponding to the color material layer of the target thermal transfer sheet There is a need to make certain about. Specifically, when specifying the type of solvent using a gas chromatography method, it is important to collect and analyze only a part of the layer corresponding to the color material layer of the target thermal transfer sheet. .

  And at least one of the two or more colorant components specified above is a colorant component that can be dissolved in the solvent specified above, and at least one of the two or more colorant components is specified. When the colorant component is dispersible in the solvent, it can be determined that the target thermal transfer sheet satisfies the invention specific matters of the thermal transfer sheet of the present embodiment. In addition, when two or more kinds of solvents are specified in the color material layer of the target thermal transfer sheet, at least one kind of color material component is soluble in at least one of the specified solvents, When at least one colorant component is insoluble in all the specified solvents, it can be determined that the target thermal transfer sheet satisfies the invention specific matters of the thermal transfer sheet of the present embodiment. . Further, whether the specified color material component is soluble or dispersible in the specified solvent is described in the “color material for a predetermined solvent (sublimation dye” described in the production method of the first embodiment. )), And can be specified.

  Hereinafter, each structure of the thermal transfer sheet of 1st Embodiment is demonstrated concretely using FIG. In addition, the thermal transfer sheet of 1st Embodiment respond | corresponds to the manufacturing method of the said 1st Embodiment, Unless there is particular notice, what was demonstrated in the said 1st Embodiment can be used as it is.

  There is no limitation in particular about the base material 1, The base material demonstrated with the manufacturing method of the said 1st Embodiment can be selected suitably, and can be used.

(Color material layer)
The color material layer 2 contains a binder resin, a sublimable dye, a color material, and a predetermined solvent. About each component, what was demonstrated by the manufacturing method of the said 1st Embodiment can be selected suitably, and can be used. In addition, the sublimation dye said by this embodiment means the sublimation dye which can be melt | dissolved in a predetermined solvent, and a color material means the color material which can be disperse | distributed to a predetermined solvent.

  The content ratio between the sublimable dye contained in the color material layer and the color material is not particularly limited, and is appropriately set according to functions required for the color material layer, for example, light resistance and density characteristics. Can do.

  Moreover, the color material layer 2 may contain arbitrary components, such as a mold release agent. For example, by allowing the color material layer 2 to contain a release agent, it is possible to improve the releasability between the color material layer 2 and the receiving layer during image formation. In addition, when the releasability countermeasure is taken on the receiving layer side, it is not particularly necessary that the colorant layer 2 contains a release agent.

  Examples of the releasing agent include silicone oil, polyethylene wax, amide wax, Teflon (registered trademark), fluorine-based and phosphate-based surfactants, and the like. Although there is no limitation in particular about content of the mold release agent in the coating liquid for color material layers, In the range of 0.1 mass% or more and 10 mass% or less with respect to solid content total amount of the binder resin contained in a color material layer. It is preferable that By including a release agent within this range, even if the release layer contains no release agent, the release property between the colorant layer 2 and the reception layer can be sufficiently satisfied. .

(Dye primer layer)
A dye primer layer (not shown) may be provided between the base material 1 and the color material layer 2. By providing the dye primer layer, the adhesion between the substrate 1 and the color material layer 2 can be improved, and the color material layer 2 can be prevented from being abnormally transferred during image formation. Further, by using a material having a low dye dyeing property as the dye primer layer, the printing density can be improved as compared with the case without the dye primer layer.

  The resins constituting the dye primer layer include polyester resins, polyvinyl pyrrolidone resins, polyvinyl alcohol resins, hydroxyethyl cellulose, polyacrylate resins, polyvinyl acetate resins, polyurethane resins, styrene acrylate resins, polyacrylamide resins. Examples thereof include resins, polyamide resins, polyether resins, polystyrene resins, polyethylene resins, polypropylene resins, polyvinyl chloride resins, polyvinyl acetal resins such as polyvinyl acetoacetal and polyvinyl butyral, and the like.

  The dye primer layer can also be composed of colloidal inorganic pigment ultrafine particles. According to this configuration, abnormal transfer of the dye layer to the thermal transfer image receiving sheet during image formation can be more effectively prevented. Furthermore, the transfer of the sublimable dye from the dye layer to the dye primer layer at the time of image formation can be prevented. Thereby, the dye diffusion to the receiving layer side of the thermal transfer image receiving sheet can be effectively performed, and an image having a high printing density can be formed.

  As the colloidal inorganic pigment ultrafine particles, conventionally known compounds can be used. For example, silica (colloidal silica), alumina or alumina hydrate (alumina sol, colloidal alumina, cationic aluminum oxide or hydrate, pseudoboehmite, etc.), aluminum silicate, magnesium silicate, magnesium carbonate, magnesium oxide, oxidation Examples include titanium. In particular, colloidal silica and alumina sol are preferably used. These colloidal inorganic pigment ultrafine particles have a primary average particle size of 100 nm or less, preferably 50 nm or less.

For the dye primer layer, the resin exemplified above and the coating solution for the dye primer layer in which the colloidal inorganic pigment ultrafine particles are dissolved or dispersed in an appropriate solvent are used as a gravure coating method, a roll coating method, a screen printing method, and a gravure plate. It can be formed by coating and drying by a conventionally known forming means such as the reverse roll coating method used. The coating amount of the dye coating solution for a primer layer is preferably 0.02g / m ² ~1.0g / m ² approximately.

(Heat resistant slipping layer)
As shown in FIG. 1, a heat resistant slipping layer 5 may be provided on the other surface of the substrate 1. There is no limitation in particular about binder resin which comprises the heat resistant slipping layer 5, It can form by selecting suitably a conventionally well-known thermoplastic resin etc. suitably. Examples of the thermoplastic resin include polyester resins, polyacrylate resins, polyvinyl acetate resins, styrene acrylate resins, polyurethane resins, polyethylene resins, polypropylene resins, and other polyolefin resins, polystyrene resins. Polyvinyl acetal resins such as polyvinyl chloride resins, polyether resins, polyamide resins, polyimide resins, polyamide imide resins, polycarbonate resins, polyacrylamide resins, polyvinyl chloride resins, polyvinyl butyral resins, polyvinyl acetoacetal resins And the like, and these silicone-modified products.

  Moreover, it is preferable that the heat resistant slipping layer 5 contains a lubricant for improving slipperiness with the thermal head. The lubricant is an arbitrary structure in the heat resistant slipping layer 5. Examples of the lubricant include phosphoric acid esters, fatty acid esters, metal soaps, Wax, graphite powder, fluorine-modified graft polymers, fluorine-modified block polymers, silicone oils, silicone-modified graft polymers, silicone polymers such as silicone-modified block polymers, and the like. It can be appropriately selected and used. Among the above-mentioned lubricant components, phosphate ester, fatty acid ester, metal soap, and Wax can be particularly preferably used in the present invention.

  Examples of the metal soap include polyvalent metal salts of alkyl phosphate esters, polyvalent metal salts of fatty acids, metal salts of alkyl carboxylic acids, and the like, and known additives for plastics can be used. In the present invention, zinc stearate and / or zinc stearyl phosphate can be preferably used.

  Examples of the phosphate ester include (1) a phosphoric acid monoester or diester of a saturated or unsaturated higher alcohol having 6 to 20 carbon atoms, and (2) a phosphoric acid monoester of a polyoxyalkylene alkyl ether or polyoxyalkylene alkyl allyl ether. Ester or diester, (3) phosphoric acid monoester or diester of the above-mentioned saturated or unsaturated higher alcohol alkylene oxide adduct (average number of added moles of 1 to 8), (4) alkylphenol having an alkyl group of 8 to 12 carbon atoms Alternatively, phosphoric acid monoester or diester of alkyl naphthol can be used. Examples of the saturated or unsaturated higher alcohol in the above (1) and (3) include cetyl alcohol, stearyl alcohol, oleyl alcohol and the like. Examples of the alkylphenol in the above (3) include nonylphenol, dodecylphenol, diphenylphenol and the like.

  The method for forming the heat-resistant slip layer 5 is not particularly limited, and a gravure printing method, a screen printing method, and a gravure plate are prepared by dissolving or dispersing a binder resin and a lubricant added as necessary in an appropriate solvent. It can form by apply | coating on the base material 1 using well-known coating means, such as the reverse roll coating method using this, and drying. Examples of the solvent used for preparing the coating liquid include water, toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methanol, ethanol, isopropyl alcohol, dimethylformamide, ethyl acetate, butyl acetate, ethylene glycol, dimethylacetamide, Examples thereof include dimethyl sulfoxide.

(Primer layer for heat-resistant slip layer)
Further, a primer layer (not shown) for a heat resistant slipping layer may be provided between the base material 1 and the heat resistant slipping layer 5. The primer layer for the heat resistant slipping layer is a layer provided in order to improve the adhesion between the substrate 1 and the heat resistant slipping layer 5, and is an arbitrary layer. Examples of the primer layer for the heat resistant slipping layer include polyester resin, polyurethane resin, acrylic resin, polycarbonate resin, polyamide resin, polyimide resin, polyamideimide resin, vinyl chloride / vinyl acetate copolymer, polyvinyl butyral resin, polyvinyl alcohol resin, polyvinyl Examples include pyrrolidone resins. Moreover, you may contain the electrically conductive material for providing electroconductivity suitably. Examples thereof include sulfonated polyaniline, carbon particles, silver particles, and gold particles.

<Thermal transfer sheet of the second embodiment>
A thermal transfer sheet 100 according to the second embodiment is a thermal transfer sheet in which a color material layer 2 is provided on a base material 1 as shown in FIG. 2, and the color material layer 2 is first from the base material side. The color material layer 2C and the second color material layer D are laminated in this order, and the first color material layer 2C is a sublimation that is soluble in the first solvent and the first solvent. The second color material layer 2D contains a second solvent and a color material dispersible in the second solvent.

  According to the thermal transfer sheet of the second embodiment including the color material layer 2 having the above characteristics, the second color material layer 2D covers the sublimable dye localized at the interface in the first color material layer 2C. Therefore, for the reason described in the manufacturing method of the second embodiment, it is possible to prevent the occurrence of kicks and scumming and to form a high-density image.

  In the present embodiment, the first color material layer 2C includes the first solvent, and the second color material layer 2D includes the second solvent. Similar to the thermal transfer sheet of the first embodiment, the first solvent and the second solvent are not intended to be actively included in the first color material layer 2C and the second color material layer 2D, respectively. Instead, the first solvent is a residual solvent contained in the first color material layer 2C, and the second solvent is a residual solvent contained in the second color material layer 2D. Specifically, the first solvent remaining in the first color material layer 2C is a solvent that can dissolve the sublimable dye contained in the first color material layer, and the second color material. When the second solvent remaining in the layer 2D is a solvent that can disperse the color material contained in the second color material layer 2D, the thermal transfer sheet of this embodiment is the second embodiment. The same effect as the thermal transfer sheet manufactured by the manufacturing method of the form is exhibited.

  As long as the sublimation dye in the first color material layer 2C and the color material dissolution / dispersion conditions in the second color material layer 2D satisfy the above-described relationship, the manufacturing method of the second embodiment has been described. In addition, the first solvent remaining in the first color material layer 2C and the second solvent remaining in the second color material layer 2D may be a common residual solvent. In this case, the condition is that the first color material layer 2C contains at least one sublimable dye that can be dissolved in the common solvent. In addition, the second color material layer is required to include at least one color material that can be dispersed in a common solvent. In addition, the sublimable dye contained in the first color material layer 2C and the color material contained in the second color material layer 2D may be the same color material. In this case, in the first color material layer 2C, the first solvent capable of dissolving the same color material remains, and in the second color material layer 2D, the first color material layer 2D can disperse the same color material. The condition is that 2 solvents remain.

  Whether or not the target thermal transfer sheet satisfies the invention specific matters of the thermal transfer sheet of the present embodiment can be determined by the relationship between the solvent contained in each layer and the color material component. Specifically, when the color material layer in the target thermal transfer sheet does not have a laminated configuration, it can be determined that the target thermal transfer sheet does not satisfy the invention-specific matters of the thermal transfer sheet of the present embodiment. On the other hand, when the color material layer of the target thermal transfer sheet has a laminated structure, the solvent and the color material component included in the color material layer close to the base material are specified. At this time, when the color material component is a color material component that can be dissolved in the specified solvent, it can be determined that the color material component has the configuration of the first color material layer. Next, the solvent contained in the color material layer far from the base material and the color material component are specified. At this time, when the color material component is a color material component dispersible in the specified solvent, it can be determined that the color material component has the configuration of the second color material layer, and the first color material layer, and When layers having the same configuration as the second color material layer are laminated, it can be determined that the target thermal transfer sheet satisfies the invention-specific matters of the thermal transfer sheet of the present embodiment. The method described in the first embodiment can be used as it is for specifying the color material component and the solvent. Further, whether the specified color material component is soluble or dispersible in the specified solvent is described in the “color material for a predetermined solvent (sublimation dye” described in the production method of the first embodiment. )), And can be specified.

  Hereinafter, each structure of the thermal transfer sheet of 2nd Embodiment is demonstrated concretely using FIG. Note that the thermal transfer sheet of the second embodiment corresponds to the thermal transfer sheet manufactured by the manufacturing method of the second embodiment, and unless otherwise specified, the one described in the first embodiment can be used as it is. it can.

  There is no limitation in particular about the base material 1, The base material demonstrated with the manufacturing method of the said 1st Embodiment can be selected suitably, and can be used.

(First color material layer)
The first color material layer 2C contains a binder resin, a first solvent, and a sublimable dye that can be dissolved in the first solvent. About each component, what was demonstrated with the 1st coating liquid of the manufacturing method of the said 2nd Embodiment can be selected suitably, and can be used.

  Further, the first color material layer may contain a color material that can be dispersed in the first solvent. In addition to the binder resin, the first solvent, and the sublimable dye that can be dissolved in the first solvent, the first color material layer 2C is described in the first coating liquid of the manufacturing method of the second embodiment. Various optional components may be contained.

  As a method of forming the first color material layer 2C, the method described in the manufacturing method of the second embodiment may be used. Hereinafter, the same applies to the second color material layer 2D.

(Second color material layer)
The second color material layer 2D includes a binder resin, a second solvent, and a color material that can be dispersed in the second solvent. About each component, what was demonstrated with the 2nd coating liquid of the manufacturing method of the said 2nd Embodiment can be selected suitably, and can be used.

  The second color material layer 2D may contain a color material that can be dissolved in the second solvent. In addition to the binder resin, the second solvent, and the color material dispersible in the second solvent, the second color material layer 2D has been described in the second coating liquid of the manufacturing method of the second embodiment. Various arbitrary components may be contained.

  Further, in the thermal transfer sheet of the second embodiment, a dye primer layer may be provided between the substrate 1 and the first color material layer 2C, similarly to the thermal transfer sheet of the first embodiment. A heat resistant slipping layer may be provided on the other surface of the substrate 1. Moreover, the primer layer for heat resistant slipping layers may be provided between the base material 1 and the heat resistant slipping layer.

  The thermal transfer sheet 100 of the present invention has been specifically described above, but various modifications can be made without departing from the spirit of the present invention. For example, in the configuration shown in FIGS. 1 and 2, an integrated thermal transfer sheet in which a color material layer 2 and a transferable protective layer (not shown) are provided in the same order on the same surface of the substrate 1 may be used. In addition, color material layers having different hues may be provided in the surface order on the same surface of the substrate 1. For example, on the base material 1, a yellow color material layer, a magenta color material layer, and a cyan color material layer may be provided in the surface order. In this case, at least one of the color material layers provided in the surface order may have the color material layer described in the first embodiment or the second embodiment described above. Further, all the color material layers may be the color material layers described in the first embodiment or the second embodiment. Moreover, it can also be set as the structure which combined the thermal transfer sheet of 1st Embodiment and the thermal transfer sheet of 2nd Embodiment.

  Next, an Example is given and this invention is demonstrated further more concretely. Hereinafter, unless otherwise specified, “part” and “%” are based on mass. Further, unless otherwise specified, “parts” and “%” indicate solid content values.

Example 1
Using a polyethylene terephthalate film with a thickness of 4.5 μm as the base material, a coating solution for the heat resistant slipping layer having the following composition is applied to one surface of the base material in terms of solid content. The heat-resistant slipping layer was formed by applying and drying at 0.5 g / m ² . Next, on the other surface of the base material, a dye primer layer coating solution having the following composition is applied so that the coating amount is 0.1 g / m ^{2 in} terms of solid content, and dried to form a dye. A primer layer was formed. Next, the colorant layer coating solution 1 produced by the following method is applied on the dye primer layer so that the coating amount is 1.0 g / m ^{2 in} terms of solid content, and dried. The thermal transfer sheet of Example 1 was obtained by forming the color material layer.

Whether the sublimable dye or the color material contained in the following color material layer coating solution is soluble or dispersible in a toluene / methyl ethyl ketone mixed solvent was determined in advance by the following method.
Using a mixed solvent of toluene / methyl ethyl ketone = 1/1, a sublimation dye or a coloring material was added so that the concentration was 2 w / v%, and the mixture was heated and stirred at 50 ° C. for 1 hour. Subsequently, after leaving the obtained liquid at 25 degreeC for 60 hours, the presence or absence of precipitation of a sublimation dye or a coloring material was confirmed visually. As a result of the confirmation, if there is no precipitation of the sublimation dye or the coloring material, it is determined that the dye is a dissolvable sublimation dye or the coloring material. It was judged.

  Based on the above determination, “dispers yellow 201” contained in the color material layer coating liquid 1 and the following color material layer coating liquid 2 is a sublimable dye that can be dissolved in a toluene / methyl ethyl ketone mixed solvent. “Disperse Yellow 54” contained in the color material layer coating solution 1 and the following color material layer coating solution 3 was determined to be a color material dispersible in a toluene / methyl ethyl ketone mixed solvent. Further, the dye represented by the following general formula (4) contained in the following coating material 4 for the color material layer was determined to be a sublimable dye that can be dissolved in a toluene / methyl ethyl ketone mixed solvent. The “sulfonated derivative of CI Pigment Yellow 138” represented by the following general formula (3) functions as “a dispersant for improving the dispersibility of Disperse Yellow 54”.

<Coating fluid for heat resistant slipping layer>
・ Polyvinyl acetal resin 60.8 parts (ESREC KS-1 Sekisui Chemical Co., Ltd.)
・ Polyisocyanate 4.2 parts (Bernock D750 Dainippon Ink & Chemicals, Inc.)
-Zinc stearyl phosphate 10 parts (LBT-1830 purification Sakai Chemical Industry Co., Ltd.)
・ Zinc stearate 10 parts (SZ-PF Sakai Chemical Industry Co., Ltd.)
・ Talc 5 parts (Microace P-3 Nihon Talc Industry Co., Ltd.)
・ 10 parts of polyethylene wax (polyethylene wax 3000 Toyo Adre Co., Ltd.)
・ Toluene 200 parts ・ Methyl ethyl ketone 100 parts

<Dye primer layer coating solution>
・ Alumina sol (average primary particle size 10 × 100 nm, solid content 10%) 30 parts (alumina sol 200 Nissan Chemical Industries, Ltd.)
・ 3 parts of polyvinylpyrrolidone resin (K-90 ISP)
・ Water 50 parts ・ Isopropyl alcohol 17 parts

(Preparation of coating material 1 for color material layer)
As shown in the composition of the colorant layer coating liquid 1 below, a colorant, a dispersant, a binder resin, a polyethylene wax, a solvent, and 250 parts by mass of a 2.0 mm zirconia bead are placed in a glass bottle and hermetically sealed. Shake with a paint shaker (manufactured by Asada Tekko Co., Ltd.) for 1 hour, then remove the zirconia beads, and then put 250 parts by mass of zirconia beads with a particle size of 0.1 mm into a glass bottle. Then, dispersion was performed for 24 hours to prepare a coating material 1 for color material layer.

<Coloring material layer coating solution 1>
Disperse Yellow 201 2.3 parts Disperse Yellow 54 2.3 parts Pigment represented by the following general formula (3) 0.42 parts (sulfonated derivative of CI Pigment Yellow 138)
-Acrylic block type polymer dispersant 1.7 parts (BYK-LPN21116 weight average molecular weight 8000 manufactured by Big Chemie)
-Polyvinylacetoacetal resin 2.05 parts (KS-5 Sekisui Chemical Co., Ltd.)
・ Polyethylene wax (particle size 5μm) 0.09 parts ・ Toluene 33 parts ・ Methyl ethyl ketone 33 parts

(Example 2)
Instead of the color material layer coating liquid 1 of Example 1, the color material layer coating liquid 2 produced by the following method was applied so that the coating amount was 0.5 g / m ^{2 in} terms of solid content. The first color material layer is formed by coating on a base material and drying, and the coating amount of the color material layer coating liquid 3 having the following composition is solid on the first color material layer. coated min terms so that 0.5 g / m ^2, except for forming a second color material layer by drying, in the same manner as in example 1, and the first color material layer first The thermal transfer sheet of Example 2 provided with the color material layer formed by laminating the 2 color material layers was obtained. The color material layer coating solution 3 was produced by the same production method as the color material layer coating solution 1 described above.

(Preparation of coating material 2 for color material layer)
According to the composition of the following coating solution 2 for the color material layer, the color material, the binder resin, the polyethylene wax and the solvent are put in a glass bottle, sealed, heated at 50 ° C. for 1 hour, and then 30 by a paint shaker (manufactured by Asada Tekko). The colorant layer coating liquid 2 was prepared by shaking.

<Coloring material layer coating solution 2>
・ Disperse Yellow 201 3.51 parts ・ Polyvinylacetoacetal resin 2.63 parts (KS-5 Sekisui Chemical Co., Ltd.)
・ Polyethylene wax 0.06 parts (particle size 5μm)
・ Toluene 33 parts ・ Methyl ethyl ketone 33 parts

<Colorant layer coating solution 3>
Disperse Yellow 54 3.31 parts Pigment represented by the above general formula (3) 0.20 parts (sulfonated derivative of CI Pigment Yellow 138)
-Acrylic block type polymer dispersant 1.19 parts (BYK-LPN21116 weight average molecular weight 8000 manufactured by Big Chemie)
-Polyvinyl acetal resin 1.44 parts (KS-5 Sekisui Chemical Co., Ltd.)
・ Toluene 33 parts ・ Methyl ethyl ketone 33 parts

(Example 3)
Disperse Yellow 201 (2.3 parts) in Color Material Layer Coating Liquid 1 is changed to a sublimable dye (2.3 parts) represented by the following general formula (4). A thermal transfer sheet of Example 3 was obtained in the same manner as Example 1 except that was used.

(Comparative Example 1)
The color material layer coating liquid 1 is changed to the color material layer coating liquid 2 having the above composition, and the color material layer coating liquid 2 is applied in an amount of 1.0 g / m ^{2 in} terms of solid content. The thermal transfer sheet of Comparative Example 1 was obtained in the same manner as in Example 1 except that the color material layer was formed by coating and drying.

(Comparative Example 2)
The color material layer coating liquid 1 is changed to the color material layer coating liquid 3 having the above composition, and the color material layer coating liquid 3 is applied in an amount of 1.0 g / m ^{2 in} terms of solid content. The thermal transfer sheet of Comparative Example 2 was obtained in the same manner as in Example 1 except that the color material layer was formed by coating and drying.

(Comparative Example 3)
Disperse yellow 201 (3.51 parts) of the color material layer coating liquid 2 was changed to the color material (3.51 parts) of the above general formula (4) to prepare a color material layer coating liquid A. Example 1 except that the color material layer coating liquid A was applied so that the coating amount was 1.0 g / m ^{2 in} terms of solid content and dried to form a color material layer. In the same manner, a thermal transfer sheet of Comparative Example 3 was obtained.

(Print density evaluation)
Using a test printer, each thermal transfer sheet of each Example and Comparative Example was combined with a thermal transfer image-receiving sheet prepared under the following conditions, and a gradation pattern was printed under the following printing conditions to examine density characteristics. The density characteristics were evaluated at the maximum density when the maximum energy was applied, and the print density was evaluated based on the following evaluation criteria. The reflection density was measured with a spectrophotometer (Spectrolino, manufactured by Gretag Macbeth Co.). The evaluation results are shown in Table 1.

(Printing conditions)
・ Thermal head: F3598 (Toshiba Hokuto Electronics Co., Ltd.)
-Heating element average resistance: 5176 (Ω)
・ Print density in the main scanning direction: 300 dpi
-Sub-scanning direction printing density: 300 dpi
・ Printing power: 0.12 (W / dot)
1 line cycle: 2 (msec.)
・ Pulse duty: 85%
-Printing start temperature: 35.5 (° C)

"Evaluation criteria"
A: The density is 2.1 or more.
○: The concentration is 2.0 or more and less than 2.1.
(Triangle | delta): A density | concentration is less than 2.0.

(Creation of thermal transfer image receiving sheet)
On the porous film layer made of porous polyethylene film (Toyopearl-SS P4255, manufactured by Toyobo Co., Ltd., 35 μm thick), an intermediate layer coating solution and a receiving layer coating solution having the following composition are obtained by a gravure reverse coating method. The intermediate layer and the receiving layer were formed by sequentially coating and drying. The adhesive layer is formed by applying and drying to the porous polyethylene film on the opposite side of the surface on which the intermediate layer and the receiving layer are provided, using a gravure reverse roll coat method using an adhesive layer coating solution having the following composition: Then, an RC base paper (155 g / m ² , thickness 151 μm) (Mitsubishi Paper Co., Ltd.) and a thermal transfer image receiving sheet were prepared. Each of the above coating amounts was a solid content, the intermediate layer was 1.5 g / m ² , the receiving layer was 5.0 g / m ² , and the adhesive layer was 5 g / m ² .

<Intermediate layer coating solution>
・ Polyester resin 50 parts (Polyester WR-905 Nippon Synthetic Chemical Industry Co., Ltd.)
・ Titanium oxide 20 parts (TCA888 Tochem Products)
・ Fluorescent brightener 1.2 parts (Ubitex BAC Ciba Specialty Chemicals Co., Ltd.)
Water / isopropyl alcohol = 1/1 28.8 parts

<Coating solution composition for receiving layer>
・ 60 parts of vinyl chloride-vinyl acetate copolymer (Solvine C Nissin Chemical Industry Co., Ltd.)
・ Epoxy-modified silicone 1.2 parts (X-22-3000T Shin-Etsu Chemical Co., Ltd.)
・ Methylstil modified silicone 0.6 parts (X-24-510, Shin-Etsu Chemical Co., Ltd.)
・ Methyl ethyl ketone / toluene (mass ratio 1/1) 5 parts

<Coating liquid for adhesive layer>
・ Urethane resin 30 parts (Takelac A-969V Mitsui Takeda Chemical Co., Ltd.)
・ Isocyanate 10 parts (Takenate A-5 Mitsui Takeda Chemical Co., Ltd.)
・ 100 parts of ethyl acetate

(Contamination evaluation)
In order to judge the preservability of the thermal transfer sheet, the contamination property to the heat-resistant slip layer was evaluated. Contamination evaluation was performed by superposing the color material layer surface of the thermal transfer sheet of each Example and Comparative Example and the heat-resistant slip layer surface, applying a load of 20 kg / cm ² and storing it in an environment of 40 ° C. and 90% RH for 98 hours. Then, the migration of the coloring material to the heat-resistant slip layer surface was evaluated. The migration is evaluated by measuring the surface of the heat-resistant slip layer before and after storage using a spectrophotometer (Spectaglino, manufactured by Gretag Macbeth Co., Ltd.) and calculating the color difference (ΔE ^{* ab} ) using the following formula. Based on this, the contamination was evaluated. The evaluation results are also shown in Table 1. In addition, the same heat-resistant slipping layer produced with the thermal transfer sheet of each said Example and a comparative example was used for the heat-resistant slipping layer overlapped with the color material layer of the heat transfer sheet of each Example and a comparative example.
Color difference ΔE ^{* ab} = ((Δa ^* ) ² + (Δb ^* ) ² ) ^1/2
CIE1976 La ^* b ^* color system (JIS Z8729 (1980)) reference Δa ^* = a ^* (after storage) −a ^* (before storage)
Δb ^* = b ^* (after storage) −b ^* (before storage)
Note that a ^* and b ^* are based on the CIE 1976 L ^* a ^* b ^* color system, and a ^* and b ^* represent a perceptual lightness index.
Further, the smaller the value of ΔE ^{* ab,} the less the contamination, in other words, the less the degree of kick.

"Evaluation criteria"
○: ΔE ^{* ab} is less than 10.
Δ... ΔE ^{* ab} is 10 or more.

(Earth dirt evaluation)
In order to judge the preservability of the thermal transfer sheet, the background of the printed material was evaluated. For the evaluation, the thermal transfer sheets of each Example and Comparative Example were stored in an environment of 50 ° C. and 80% RH for 60 hours, and those that were not stored were prepared, printed on a predetermined image receiving paper, and each printed matter. The white area where no energy is applied is measured with a spectrophotometer (Spectrolino, manufactured by Gretag Macbeth Co., Ltd.), and the color difference (ΔE ^{* ab} ) is determined by the following formula. Was evaluated. The evaluation results are also shown in Table 1.
Color difference ΔE ^{* ab} = ((Δa ^* ) ² + (Δb ^* ) ² ) ^1/2
CIE1976 La ^* b ^* color system (JIS Z8729 (1980)) reference Δa ^* = a ^* (after storage) −a ^* (before storage)
Δb ^* = b ^* (after storage) −b ^* (before storage)
Note that a ^* and b ^* are based on the CIE 1976 L ^* a ^* b ^* color system, and a ^* and b ^* represent a perceptual lightness index.
Moreover, it shows that the smaller the value of ΔE ^{* ab,} the less the dye precipitates in a high temperature / high humidity environment, and the higher the storage stability.

"Evaluation criteria"
A: ΔE ^{* ab} is less than 0.2.
○: ΔE ^{* ab} is 0.2 or more and less than 0.3.
Δ... ΔE ^{* ab} is 0.3 or more.

  As is clear from Table 1, the prints obtained by using the thermal transfer sheets of Examples 1 to 3 were good with the density being 2.0 or higher at the maximum density. In addition, the color material was less contaminated on the heat-resistant slip layer surface, and there was little background contamination, and the heat transfer sheet was well preserved. On the other hand, the printed matter obtained by the thermal transfer sheet obtained in Comparative Example 1 and Comparative Example 3 had a high concentration, but there were many stains on the surface of the heat-resistant slipping layer and soiling, resulting in poor storage stability. . On the other hand, although the storage stability of the thermal transfer sheet obtained in Comparative Example 2 was good, the density characteristics were low as compared with the printed matter obtained using the thermal transfer sheet of each Example.

DESCRIPTION OF SYMBOLS 1 ... Base material 2 ... Color material layer 5 ... Heat-resistant slipping layer 10x ... Sublimation dye 10y soluble in a predetermined solvent ... Color material 100 dispersible in a predetermined solvent ..Heat transfer sheet

Claims (5)

A thermal transfer sheet provided with a color material layer on one surface of a substrate,
The coloring material layer has a predetermined solvent, the specific method described below, the sublimable dye that is identified as being soluble in the predetermined solvent, the particular methods described below are dispersible in the predetermined solvent and containing a colorant is specified that,
The predetermined solvent includes one or a plurality of solvents, and when there are a plurality of the predetermined solvents, the sublimable dye is specified to be soluble in at least one of the plurality of solvents. The coloring material is a coloring material specified to be dispersible with respect to all of the plurality of solvents,
The color material is a color material represented by the following general formula (2).
A thermal transfer sheet characterized by that.
(Identification method)
A target color material is added to a predetermined solvent so as to have an amount of 2 w / v%, and the mixture is heated and stirred at 50 ° C. for 1 hour. Next, after the obtained liquid is allowed to stand at 25 ° C. for 60 hours, the presence or absence of precipitation of the target color material is visually confirmed. At this time, when precipitation of the target color material cannot be visually confirmed, the target color material is specified as a color material that can be dissolved in a predetermined solvent. On the other hand, when the deposition of the target color material can be visually confirmed, the target color material is specified as a color material that can be dispersed in a predetermined solvent. The same applies to the identification method of the sublimable dye. When there are a plurality of predetermined solvents, it is performed for each.

(R ^{1 to} R ⁵ in the general formula (2) are sulfonation derivatives substituted with a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a derivative thereof, a sulfonic acid group (—SO ₃ H), or a sulfonamide group. Represents a group.) A thermal transfer sheet provided with a color material layer on one surface of a substrate,
The color material layer has a laminated structure in which the first color material layer and the second color material layer are laminated in this order from the base material side,
The first color material layer contains a first solvent and a sublimable dye specified to be soluble in the first solvent by the following specifying method ,
When the first solvent includes one or a plurality of solvents, and the first solvent includes the plurality of solvents, the sublimable dye may be added to at least one of the plurality of solvents. A sublimable dye identified as soluble,
The second color material layer contains a second solvent and a color material specified as dispersible in the second solvent by the following specifying method ,
When the second solvent includes one or a plurality of solvents and the second solvent includes the plurality of solvents, the coloring material can be dispersed in all of the plurality of solvents. A color material identified as being
The color material is a color material represented by the following general formula (2).
A thermal transfer sheet characterized by that.
(Identification method)
The target sublimable dye is added to the first solvent so that the amount becomes 2 w / v%, and the mixture is heated and stirred at 50 ° C. for 1 hour. Subsequently, after leaving the obtained liquid at 25 ° C. for 60 hours, the presence or absence of precipitation of the desired sublimable dye is visually confirmed. At this time, when precipitation of the target sublimable dye cannot be confirmed visually, the target sublimable dye is specified as a sublimable dye that can be dissolved in the first solvent. On the other hand, when the precipitation of the target sublimable dye can be confirmed visually, the target sublimable dye is specified as a sublimable dye dispersible in the first solvent. When there are a plurality of first solvents, the process is performed for each.
The target colorant is added to the second solvent so as to have an amount of 2 w / v%, and the mixture is heated and stirred at 50 ° C. for 1 hour. Next, after the obtained liquid is allowed to stand at 25 ° C. for 60 hours, the presence or absence of precipitation of the target color material is visually confirmed. At this time, when the deposition of the target color material cannot be visually confirmed, the target color material is specified as a color material that can be dissolved in the second solvent. On the other hand, when the precipitation of the target color material can be confirmed visually, the target color material is specified as a color material that can be dispersed in the second solvent. When there are a plurality of second solvents, the measurement is performed for each.

(R ^{1 to} R ⁵ in the general formula (2) are sulfonation derivatives substituted with a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a derivative thereof, a sulfonic acid group (—SO ₃ H), or a sulfonamide group. Represents a group.) A method for producing a thermal transfer sheet, comprising:
Including a step of forming a color material layer by coating a coating material for a color material layer on a base material;
As the colorant layer coating solution, a predetermined solvent, the specific method described below, the sublimable dye that is identified as being soluble in the predetermined solvent, the particular methods described below, to the predetermined solvent A coating solution containing a colorant specified to be dispersible is used ,
The predetermined solvent includes one or a plurality of solvents, and when there are a plurality of the predetermined solvents, the sublimable dye is specified to be soluble in at least one of the plurality of solvents. The coloring material is a coloring material specified to be dispersible with respect to all of the plurality of solvents,
The color material is a color material represented by the following general formula (2).
A method for producing a thermal transfer sheet.
(Identification method)
A target color material is added to a predetermined solvent so as to have an amount of 2 w / v%, and the mixture is heated and stirred at 50 ° C. for 1 hour. Next, after the obtained liquid is allowed to stand at 25 ° C. for 60 hours, the presence or absence of precipitation of the target color material is visually confirmed. At this time, when precipitation of the target color material cannot be visually confirmed, the target color material is specified as a color material that can be dissolved in a predetermined solvent. On the other hand, when the deposition of the target color material can be visually confirmed, the target color material is specified as a color material that can be dispersed in a predetermined solvent. The same applies to the identification method of the sublimable dye. When there are a plurality of predetermined solvents, it is performed for each.

(R ^{1 to} R ⁵ in the general formula (2) are sulfonation derivatives substituted with a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a derivative thereof, a sulfonic acid group (—SO ₃ H), or a sulfonamide group. Represents a group.)   The method for producing a thermal transfer sheet according to claim 3, wherein the coating liquid further contains a dispersant. A method for producing a thermal transfer sheet, comprising:
On the base material, a first colorant is coated with a coating liquid containing a first solvent and a sublimable dye specified to be soluble in the first solvent by the following specific method. Forming a layer;
On the first color material layer, a coating solution containing a second solvent and a color material specified as dispersible in the second solvent is applied by the following specifying method , Forming a colorant layer of 2;
Only including,
When the first solvent includes one or a plurality of solvents, and the first solvent includes the plurality of solvents, the sublimable dye may be added to at least one of the plurality of solvents. A sublimable dye identified as soluble,
When the second solvent includes one or a plurality of solvents and the second solvent includes the plurality of solvents, the coloring material can be dispersed in all of the plurality of solvents. A color material identified as being
The color material is a color material represented by the following general formula (2).
A method for producing a thermal transfer sheet.
(Identification method)
The target sublimable dye is added to the first solvent so that the amount becomes 2 w / v%, and the mixture is heated and stirred at 50 ° C. for 1 hour. Subsequently, after leaving the obtained liquid at 25 ° C. for 60 hours, the presence or absence of precipitation of the desired sublimable dye is visually confirmed. At this time, when precipitation of the target sublimable dye cannot be confirmed visually, the target sublimable dye is specified as a sublimable dye that can be dissolved in the first solvent. On the other hand, when the precipitation of the target sublimable dye can be confirmed visually, the target sublimable dye is specified as a sublimable dye dispersible in the first solvent. When there are a plurality of first solvents, the process is performed for each.
The target colorant is added to the second solvent so as to have an amount of 2 w / v%, and the mixture is heated and stirred at 50 ° C. for 1 hour. Next, after the obtained liquid is allowed to stand at 25 ° C. for 60 hours, the presence or absence of precipitation of the target color material is visually confirmed. At this time, when the deposition of the target color material cannot be visually confirmed, the target color material is specified as a color material that can be dissolved in the second solvent. On the other hand, when the precipitation of the target color material can be confirmed visually, the target color material is specified as a color material that can be dispersed in the second solvent. When there are a plurality of second solvents, the measurement is performed for each.

(R ^{1 to} R ⁵ in the general formula (2) are sulfonation derivatives substituted with a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a derivative thereof, a sulfonic acid group (—SO ₃ H), or a sulfonamide group. Represents a group.)

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