JP2016117163A - Coating liquid for coloring material layer, and method for producing sublimation type thermal transfer sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a sublimation type thermal transfer sheet capable of suppressing the occurrence of kickback or scumming without a specific limitation to a coloring material contained in a coloring material layer; and to provide a coating liquid for a coloring material layer used in the production method.SOLUTION: In a coating liquid for a coloring material layer for forming a coloring material layer 2 of a sublimation type thermal transfer sheet 100, the coating liquid for the coloring material layer contains a predetermined solvent, a coloring material 10X dispersible in the predetermined solvent, a dispersant, and (i) a polyvinyl acetal resin having a number average molecular weight (Mn) of 40,000 or less or (ii) a nitrocellulose resin of L1/8 or less or H1/8 or less by type and viscosity symbols according to JISK6703 (1995).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a coating material for a color material layer and a method for producing a sublimation 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 substrate. 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.

  A sublimation type thermal transfer sheet used in a sublimation type recording method is generally stored in a state wound around a predetermined winding diameter, and the color material contained in the color material layer is exposed to the surface of the color material layer by bleeding or the like. In the case where the dye is present in a localized state, the sublimable dye is likely to shift (so-called kick) to the back layer side of the thermal transfer sheet. When the sublimation dye transferred to the back layer side is transferred again to the color material layer side (so-called back), in particular, in the thermal transfer sheet in which the color material layers of the different colors are provided in the surface order. When the sublimation dye transferred to the back layer side is transferred to another color material layer having a hue different from that of the sublimation dye, color development characteristics are reduced during image formation using the other color material layer. cause. In addition, when the color material layer has low storage stability, it causes scumming.

  Under such circumstances, various studies have been made on thermal transfer sheets for preventing the occurrence of kicks. For example, Patent Document 1 discloses that a dye layer is provided on one surface of a base material. In the thermal transfer sheet provided with a back layer on the other side, an indoaniline-based dye, a polyvinyl acetal resin A, and a polyvinyl acetal resin B (polyvinyl acetal represented by the general formula (1) in Patent Document 1) A thermal transfer sheet containing a resin is proposed. According to this thermal transfer sheet, the dye can be prevented from transferring to the back layer during storage of the thermal transfer sheet. However, in the thermal transfer sheet proposed in Patent Document 1, since the dye species and the 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.

JP 2009-286060 A

  The present invention has been made in view of such a situation, and sublimation type thermal transfer capable of suppressing the occurrence of kick and background contamination without being particularly restricted by the color material contained in the color material layer. It is a main subject to provide a sheet manufacturing method and a coating material for a color material layer used in the manufacturing method.

  The present invention for solving the above problems is a color material layer coating liquid for forming a color material layer of a sublimation thermal transfer sheet, which contains a predetermined solvent, a color material, a dispersant, and a binder resin. The colorant is a colorant dispersible in the predetermined solvent, and the binder resin is (i) a polyvinyl acetal resin having a number average molecular weight (Mn) of 40000 or less, or (ii) JIS K It is characterized by being a nitrocellulose resin having a type and viscosity symbol of 6703 (1995) of L1 / 8 or less, or H1 / 8 or less.

  Moreover, the said coating material for color material layers may contain the color material shown by following General formula (1) and following General formula (2) as a color material dispersible in the said predetermined solvent. .

一般式（１）におけるＸは水素原子、又はハロゲン原子を表し、Ｒ¹は水素原子、炭素数１〜５のアルキル基、若しくはその誘導体、又はアルキル基、若しくはベンゼン環を含む総炭素数６〜１０のアシル基を表す。

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.

一般式（２）におけるＲ¹〜Ｒ⁵は水素原子、炭素数１〜５のアルキル基、若しくはその誘導体又はスルホン酸基（−ＳＯ₃Ｈ）、又はスルホンアミド基で置換させたスルホン化誘導基を表す。

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.

  Further, the color material layer coating liquid may be one or two or more selected from the group consisting of a polyether dispersant, a graft polymer dispersant, and an acrylic block polymer dispersant as the dispersant. You may contain.

  The color material layer coating solution may further contain a sublimable dye that can be dissolved in the predetermined solvent.

  Moreover, this invention for solving the said subject is a manufacturing method of a sublimation type | mold thermal transfer sheet, Comprising: The color material layer coating liquid is applied on one surface of a base material, and a color material layer is formed. The color material layer coating liquid contains a predetermined solvent, a color material dispersible in the predetermined solvent, a dispersant, and a binder resin, and the color material layer coating liquid comprises The binder resin to be contained is (i) a polyvinyl acetal resin having a number average molecular weight (Mn) of 40000 or less, or (ii) a type and viscosity symbol in JIS K 6703 (1995) of L1 / 8 or less, or H1 / 8 or less. It is a nitrocellulose resin.

  According to the coating material for a color material layer and the method for producing a sublimation type thermal transfer sheet of the present invention, the occurrence of kick and background stains is suppressed without any particular restriction on the color material contained in the color material layer. A sublimation type thermal transfer sheet can be obtained.

It is a schematic sectional drawing of a sublimation type thermal transfer sheet provided with a color material layer formed using the color material layer coating liquid of one embodiment. It is a schematic sectional drawing of a sublimation type thermal transfer sheet provided with a color material layer formed using the color material layer coating liquid of one embodiment. It is a schematic sectional drawing of a sublimation type thermal transfer sheet provided with a color material layer formed using the color material layer coating liquid of one embodiment. It is a schematic sectional drawing of a sublimation type thermal transfer sheet provided with the dye layer formed using the coating liquid for comparative dye layers.

<< Color Material Layer Coating Liquid of One Embodiment >>
Hereinafter, a coating material for a color material layer according to an embodiment of the present invention (hereinafter may be referred to as a coating material for a color material layer according to an embodiment) will be described. The color material layer coating liquid according to an embodiment is a coating liquid used for forming a color material layer of a sublimation thermal transfer sheet, and includes, as essential components, a predetermined solvent, a color material, a dispersant, And a binder resin (hereinafter, these essential components may be collectively referred to as condition 1). The color material layer coating liquid according to an embodiment is a color material in which the color material is dispersible in the predetermined solvent (hereinafter may be referred to as condition 2), and the binder resin is ( i) a polyvinyl acetal resin having a number average molecular weight (Mn) of 40000 or less, or (ii) a nitrocellulose resin having a type and viscosity symbol in JIS K 6703 (1995) of L1 / 8 or less, or H1 / 8 or less , And may be referred to as condition 3). The number average molecular weight (Mn) mentioned in the present specification means a polystyrene equivalent value measured by gel permeation chromatography (GPC).

  Hereinafter, the color material layer coating liquid of one embodiment will be described with reference to a sublimation thermal transfer sheet formed using the color material layer coating liquid of one embodiment. The sublimation-type thermal transfer sheet referred to in the present specification refers to an image formed by transferring the color material in the color material layer onto the transferred material by applying heat to the back layer side using a heating means such as a thermal head. It is a thermal transfer sheet used in the sublimation type recording method to be formed, and the color material layer coating liquid of one embodiment is a coating liquid for forming the color material layer of the sublimation type thermal transfer sheet.

  FIG. 4 shows “Comparative Dye Layer Coating Liquid (Comparative Color Material Layer Coating Liquid)” which does not satisfy the above conditions 1 to 3, specifically, a solvent, a sublimable dye 10y, and a binder resin. An example of a “comparative thermal transfer sheet” 100x provided with a dye layer 2A (coloring material layer 2A) formed using a “comparative dye layer coating solution” obtained by dissolving the sublimable dye in a solvent. It is a schematic sectional drawing which shows. In the illustrated form, the dye layer 2A is provided on one surface of the substrate 1, the back layer 5 is provided on the other surface of the substrate 1, and the presence state of the sublimable dye 10y in the dye layer 2A. Is schematically shown.

  Since the sublimable dye 10y that can be dissolved in a solvent usually has a low molecular weight and is a single molecule, the sublimable dye 10y is dissolved in a solvent as shown in FIG. In the dye layer 2 </ b> A formed using the “coating liquid”, the sublimable dye 10 y exists in a localized state at the interface of the dye layer 2 </ b> A. The thermal transfer sheet is generally stored in a small roll state, and since the color material layer and the back layer are in direct contact with each other in the small roll state, the sublimable dye 10y in the dye layer 2A is shown in FIG. When present in the state shown, the sublimable dye 10y is likely to move to the back layer 5 side of the substrate 1 when the thermal transfer sheet is stored in a small roll state. That is, in the thermal transfer sheet provided with the dye layer 2A formed using the “comparison dye layer coating liquid” that does not satisfy the conditions 1 to 3, it is impossible to prevent the occurrence of kicks and soiling.

  On the other hand, by using a sublimable dye having a high molecular weight, even if the localization of the sublimable dye to the interface can be reduced, the affinity between the high molecular weight sublimable dye 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.

  Next, the color material layer formed using the color material layer coating liquid satisfying the conditions 1 and 2 will be described. FIG. 1 shows a coating solution for a color material layer that satisfies conditions 1 and 2, specifically, a solvent, a color material 10x, a dispersant, and a binder resin, and the color material 10x is dispersed in the solvent. It is a schematic sectional drawing which shows an example of the thermal transfer sheet 100 provided with the color material layer 2 formed using the coating liquid for color material layers. In the illustrated form, the color material layer 2 is provided on one surface of the base material 1, and the back surface layer 5 is provided on the other surface of the base material 1, and the presence of the color material 10 x in the color material layer 2 is present. The state is shown schematically.

  As shown in FIG. 1, according to the color material layer 2 formed using the color material layer coating liquid in which the color material 10 x is dispersed in a solvent, the color material 10 x is contained in the color material layer 2. It can exist in a dispersed state, and it is possible to suppress the occurrence of kicks and soiling that can be caused by the sublimation dye being localized at the interface. That is, according to the color material layer 2 formed using the color material layer coating liquid that satisfies the conditions 1 and 2, it is possible to suppress the occurrence of kicks and background stains.

  By the way, in order to enable high-density image formation using a thermal transfer sheet provided with a color material layer formed using a color material layer coating solution that satisfies conditions 1 and 2, It is considered important to reduce the particle diameter of the dispersed color material 10x, in other words, to make the color material 10x exist in a fine particle state in the color material layer coating liquid.

  Here, the coating liquid for the color material layer satisfying the above conditions 1 and 2 is a polyvinyl acetal resin having a number average molecular weight (Mn) of 40000 or less as a binder resin, or a type and viscosity symbol in JIS K 6703 (1995). When the nitrocellulose resin of L1 / 8 or less or H1 / 8 or less is not contained, that is, when the binder resin satisfying the above condition 3 is not contained in the color material layer coating liquid, the paint shaker In the preparation of the color material layer coating liquid using the color material layer coating liquid, the formation of the color material layer coating liquid is hindered from being finely divided into the color material 10x contained in the color material layer coating liquid. The particle diameter of the coloring material 10x contained in the coloring material layer tends to increase. As described above, in order to form a high-density image using a thermal transfer sheet provided with a color material layer formed using a color material layer coating solution that satisfies conditions 1 and 2, the color material is used. Although it is necessary to make the color material 10x finer in the layer, if the condition 3 is not satisfied, the color material 10x can be made fine particles in the formed color material layer. Therefore, it is difficult to form a high density image.

  The mechanism by which the binder resin contained in the color material layer coating liquid satisfying conditions 1 and 2 does not satisfy the above condition 3 to inhibit the color material 10x from being finely divided is not always clear at present. Although it is not, it is guessed that it is due to the following reasons. In the case where a polyvinyl acetal resin or a nitrocellulose resin is contained as a binder resin in the color material layer coating liquid satisfying the above conditions 1 and 2, a polyvinyl acetal resin having a number average molecular weight (Mn) exceeding 40000, JIS, When a nitrocellulose resin that exceeds L1 / 8 or H1 / 8 in terms of the type and viscosity symbol in K 6703 (1995) is used, the viscosity of the coating liquid for the color material layer increases, and the color is increased accordingly. The fluidity of the coating liquid for the material layer decreases.

  When preparing a coating material for a color material layer using a paint shaker or the like, it is important to increase the number of collisions between the color materials 10x at the time of preparation in order to promote the formation of fine particles of the color material 10x. Conceivable. However, as described above, when the polyvinyl acetal resin or nitrocellulose resin that does not satisfy the above condition 3 is used as the binder resin in the coating material for the color material layer that satisfies the conditions 1 and 2, the color material layer Since the fluidity of the coating liquid for use decreases, the number of collisions of the color material 10x cannot be increased, and it is presumed that the fine formation of the color material 10x is hindered.

  Further, as the viscosity of the color material layer coating liquid increases, the stability of the color material layer coating liquid tends to decrease. Then, due to a decrease in the stability of the color material layer coating liquid, problems such as gelation of the color material layer coating liquid occur, and the color material layer is formed using this color material layer coating liquid. In such a case, the surface quality of the color material layer formed due to uneven coating is caused. In the case where the surface quality of the color material layer of the thermal transfer sheet is poor, the density of the printed matter is reduced, or defective prints are lost during image formation using the thermal transfer sheet.

  When a polyvinyl acetal resin having a number average molecular weight (Mn) exceeding 40000 is employed, the molecular chain of the polyvinyl acetal resin becomes too long, and the color material 10x is added to the molecular chain of the polyvinyl acetal resin. Entangling easily can be cited as one of the reasons that the number of collisions of the color material 10x is reduced and the fine particle formation of the color material 10x is inhibited.

  In addition, when a binder resin other than polyvinyl acetal resin and nitrocellulose resin is used, it does not depend on the number average molecular weight (Mn) of the binder resin or the viscosity of the coating liquid for the color material layer containing the binder resin. The color material 10x cannot be sufficiently finely divided. As this reason, it is guessed that the molecular structure etc. of binder resin have influenced. In addition, when a binder resin other than polyvinyl acetal resin and nitrocellulose resin is used, the releasability of the formed color material layer is lowered, and at the time of image formation using a sublimation type thermal transfer sheet provided with this color material layer However, a problem that a transfer defect is likely to occur is likely to occur.

  The coating liquid for a color material layer according to one embodiment is (i) a polyvinyl acetal resin having a number average molecular weight (Mn) of 40000 or less, (ii) a type and viscosity symbol of L1 / 8 or less in JIS K 6703 (1995), Or any one of H1 / 8 or less nitrocellulose resin may be contained, and both (i) and (ii) resins may be contained. Hereinafter, each component contained in the coating material for a color material layer according to an embodiment will be specifically described.

"Predetermined solvent"
The color material layer coating liquid of one embodiment contains a solvent capable of dispersing a color material 10x described later as an essential component. The predetermined solvent means a solvent capable of dispersing the color material 10x. That is, the predetermined solvent is not particularly limited, and can be appropriately selected according to the relationship with the color material 10x contained in the color material layer coating liquid of one embodiment. 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. A predetermined | prescribed solvent may be used individually by 1 type, and 2 or more types can also be mixed and used for it. Although there is no limitation in particular about content of a predetermined | prescribed solvent, it is contained in 500 mass% or more and 2000 mass% or less with respect to the solid content total amount contained in the coating material for color material layers of one Embodiment. Preferably it is.

"Coloring material that can be dispersed in a given solvent"
The color material layer coating liquid of one embodiment contains a color material 10x dispersible in the predetermined solvent. The color material referred to in the present specification is a concept including a sublimable dye and a pigment. The color material 10x that can be dispersed in a predetermined solvent is not particularly limited, and can be appropriately selected according to the type of the predetermined solvent. Specifically, any color material may be used as long as it is a color material 10x dispersible in the predetermined solvent contained in the color material layer coating liquid of one embodiment. 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, the dispersibility of the color material 10x in the color material layer coating liquid of one embodiment can be improved by a dispersant described later. That is, as a result, the color material 10x only needs to be present in a dispersed state in the color material layer coating liquid of one embodiment.

  In the color material layer coating liquid according to one embodiment, since the binder resin satisfying the above condition 3 is contained, the particle diameter of the color material 10x is reduced to 300 nm or less in the color material layer coating liquid. It can exist in the state which was made to exist. In addition, as the particle diameter of the color material 10x contained in the color material layer coating liquid according to one embodiment exceeds 300 nm, the color material layer coating liquid according to the one embodiment is formed. The density at the time of image formation using a thermal transfer sheet provided with a color material layer is low. The particle diameter of the color material as used herein means the average dispersed particle diameter of the color material in the color material layer coating liquid according to one embodiment. Specifically, the dispersion particle diameter of the color material particles dispersed in the dispersion medium of the color material layer coating liquid is measured by a laser light scattering particle size distribution meter. For the measurement of the particle size with this laser light scattering particle size distribution meter, the coating solution is appropriately diluted to a concentration measurable with the laser light scattering particle size distribution meter (for example, 1000). And can be measured at 23 ° C. by a dynamic light scattering method using a laser light scattering particle size distribution analyzer (for example, Nanotrack particle size distribution measuring device UPA-EX150 manufactured by Nikkiso Co., Ltd.). The average dispersed particle size here is a volume average particle size.

  The color material 10x dispersible in the predetermined solvent can be appropriately selected from sublimable dyes and pigments exemplified below according to the solvent contained in the coating liquid. Specifically, a predetermined solvent is selected, and then a color material dispersible in the predetermined solvent may be selected from sublimable dyes and pigments exemplified below.

  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) has characteristics of having light resistance, high brightness, and good dispersibility in the coating material for the color material layer. It can be preferably used as the dissolvable color material 10x.

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.

  As the sublimable dye dispersible in a predetermined solvent, one kind may be used alone, or two or more kinds may be used in combination. 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. Note that the color material layer coating liquid of one embodiment includes one or more dispersible color materials for all the solvents contained in the color material layer coating liquid. And In other words, the condition is that the color material 10x that is insoluble in all the solvents contained in the color material layer coating solution is contained. Regarding the embodiment of the color material layer coating liquid containing the sublimable dye 10y soluble in the predetermined solvent in the color material layer 2 together with the color material 10x dispersible in the predetermined solvent, the second embodiment This will be described later as a colorant layer coating solution.

  When a pigment is used as the colorant 10x dispersible in a predetermined solvent, a known organic or inorganic pigment may be appropriately selected. 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. The color material layer coating liquid contains, as a color material 10x dispersible in a predetermined solvent, a pigment represented by the following general formula (2) together with the quinophthalone dye represented by the above general formula (1). It is particularly preferred. According to the color material layer coating liquid containing the color material layer represented by the general formula (1) and the general formula (2) as the color material 10x dispersible in a predetermined solvent, a higher density image It is possible to form a color material layer that can be formed, has high light resistance and high color material dispersibility, and can sufficiently suppress kick and background stains.

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 the color material contained in the color material layer coating solution will be described. The predetermined solvent contained in the color material layer coating liquid and the color material dispersible in the predetermined solvent are not limited to this combination.

When the predetermined solvent is a mixed solvent of methyl ethyl ketone / toluene;
As the colorant dispersible in a mixed solvent of methyl ethyl ketone / toluene, for example, the pigments exemplified above, or the sublimation dyes exemplified above, for example, Disperse Yellow 54 can be used.

"Dispersant"
The colorant layer coating liquid of one embodiment contains a dispersant. According to the coating material for color material layer containing the dispersant, the dispersion stability of the color material 10x in the coating material for color material layer is improved by the synergistic effect with the binder resin satisfying the condition 3, and the color The material 10x can be made finer. Thereby, in the thermal transfer sheet provided with the color material layer formed using the color material layer coating liquid of one embodiment, it is possible to more effectively suppress the occurrence of kick and background stains, and high It is possible to form a density image.

  There is no limitation in particular about a dispersing agent, A graft type polymer dispersing agent, a polyether type dispersing agent, an acrylic type block type polymer dispersing agent, etc. can be mentioned. 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. Among these, graft type polymer dispersants, polyether type dispersants, and acrylic block type polymer dispersants are preferable in terms of excellent dispersion stability of the color material 10x in the color material layer coating liquid. Accordingly, the color material layer coating liquid of one embodiment contains one or more selected from a graft-type polymer dispersant, a polyether-based dispersant, and an acrylic block-type polymer dispersant. Preferably it is.

  Examples of the polyether dispersant include polyether carboxylic acid, polyether phosphoric acid, polyether phenol and the like. Examples of commercially available polyether dispersants include trade names DISPARLON DA234, DISPARLON DA325, Solsperse 20000 (manufactured by Lubrizol Corp.) manufactured by Enomoto Kasei Co., Ltd., and the like.

  As the graft type polymer dispersant, a polymer having a structure in which two or more branch polymers are graft-bonded to one molecule of a trunk polymer having a plurality of functional groups such as a basic group, for example, the trunk polymer portion is polyallylamine, A polymer in which the branched polymer portion is composed of a ring-opening polymer of ε-caprolactone is exemplified. Examples of the dispersant for the graft type polymer include Ajisper PB821, PB88-IP, Ajisper PB822, Ajisper PB823, Ajisper PB824, Ajisper PB827, Ajisper PB880, Ajisper PB881 (manufactured by Ajinomoto Fine Techno Co., Ltd.).

  As the acrylic block type polymer dispersant, the main chain structure of the polymer includes, for example, a methacrylic resin, an acrylic resin and the like, and in particular, a methacrylic or acrylic block type polymer dispersant having a tertiary amino group is used. preferable. The weight average molecular weight (Mw) of the block type polymer dispersant is preferably in the range of 500 to 20000, more preferably in the range of 1000 to 15000, and in the range of 3000 to 12000. Further preferred. By being within the above range, it is possible to achieve both wettability and dispersion stability with respect to the color material in the initial stage of dispersion in which the color material is uniformly dispersed. The weight average molecular weight (Mw) mentioned in the present specification means a polystyrene equivalent value measured by gel permeation chromatography (GPC). Examples of the methacrylic and acrylic block type polymer dispersant having a tertiary amino group include Disperbyk 2000, Disperbyk-2001, BYK-LPN6919, BYK-LPN21116, BYK-LPN21324 and the like manufactured by BYK Chemie.

  Although there is no limitation in particular about content of the dispersing agent in the coating liquid for color material layers, it is 100 mass parts or less with respect to 100 mass parts of color materials dispersible in a predetermined | prescribed solvent, Preferably, 0.5 mass part or more 100 parts by mass or less, more preferably 1 part by mass or more and 70 parts by mass or less, and particularly preferably 10 parts by mass or more and 50 parts by mass or less. If the content of the dispersant exceeds 100 parts by mass, the sharpness and the like may be impaired. On the other hand, when the content of the dispersant is too small, the function as the dispersant cannot be sufficiently exhibited.

"Binder resin"
The binder resin contained in the color material layer coating solution only needs to satisfy the condition 3 described above, and there is no particular limitation on the other conditions. In addition, the polyvinyl butyral resin and nitrocellulose resin which satisfy | fill the conditions 3 may each be used independently, and can also be used in combination with polyvinyl butyral resin and nitrocellulose resin. Moreover, 2 or more types of polyvinyl acetal resins which satisfy | fill the said conditions 3, and 2 or more types of nitrocellulose resins can also be used.

  As long as the polyvinyl acetal resin satisfies the condition that the number average molecular weight (Mn) is 40000 or less, the above-described various effects can be sufficiently exerted regardless of the lower limit value. it can. That is, there is no limitation on the lower limit value of the number average molecular weight (Mn) of the polyvinyl acetal resin. The lower limit of the number average molecular weight (Mn) as an example is about 10,000 or 1000. Further, as the polyvinyl acetal resin, a resin having a number average molecular weight (Mn) of 40000 or less and a viscosity of 100 mPa · s or less is particularly preferable.

  The nitrocellulose resin should just satisfy | fill the conditions of L1 / 8 or less by the kind and viscosity symbol in JISK6703 (1995), or H1 / 8 or less, and there is no limitation in particular about other conditions.

  Examples of the nitrocellulose resin satisfying the above feature 3 include L1 / 8 and L1 / 16 manufactured by Taihei Chemicals Co., Ltd., DHX3-5, DHX4-6, DHX5-10, DLX5- manufactured by Inabata Sangyo Co., Ltd. Commercial products such as 8 can also be used.

  Although there is no limitation in particular about content of the binder resin which satisfy | fills the said characteristic 3, when the mass of binder resin is less than 20 mass parts with respect to 100 mass parts of color materials dispersible in a predetermined | prescribed solvent, it is for color material layers In the case where the storage stability of a sublimation type thermal transfer sheet provided with a color material layer formed using a coating liquid tends to decrease, and exceeds 200 parts by mass, the color material in the color material layer coating liquid In addition, the print density of the printed material is reduced during image formation using a sublimation thermal transfer sheet having a color material layer formed using the color material layer coating liquid. There is a tendency. Considering this point, the content of the binder resin is preferably 20 parts by mass or more and 200 parts by mass or less with respect to 100 parts by mass of the color material dispersible in a predetermined solvent.

  The color material layer coating solution may contain other arbitrary binder resin together with the binder resin satisfying the above condition 3 within a range not impeding the gist of the present invention. Examples of the optional binder resin include cellulose resins such as ethyl cellulose resin, hydroxyethyl cellulose resin, ethyl hydroxy cellulose resin, methyl cellulose resin, and cellulose acetate resin, polyvinyl alcohol resin, polyvinyl acetate resin, polyvinyl butyral resin, and polyvinyl pyrrolidone. Examples thereof include acrylic resins such as vinyl resins, poly (meth) acrylates and poly (meth) acrylamides, polyurethane resins, polyamide resins and polyester resins. Moreover, you may contain the polyvinyl acetal resin which does not satisfy | fill the said conditions 3, and a nitrocellulose resin. These arbitrary binder resins are preferably less than 50% by mass based on the total amount of the solid content with the binder resin containing the binder resin satisfying the above condition 3.

  The coating material for the color material layer, in addition to the essential component that is the above condition 1, is a release agent, an antistatic agent, and a slipperiness with the receiving layer for improving the releasing property of the thermal transfer image-receiving sheet with the receiving layer. It may contain an organic or inorganic filler for controlling the content. Examples of the mold release agent include modified silicone oil, polyethylene wax, amide wax, Teflon (registered trademark), fluorine-based and phosphate-based surfactants, and the like.

"Method for identifying dispersibility of coloring materials in a given solvent"
Whether or not the color material contained in the color material layer coating solution can be dispersed 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.

"Identification method of binder resin, dispersant, coloring material and residual solvent"
Whether the color material layer included in the target thermal transfer sheet (hereinafter referred to as the target thermal transfer sheet) is formed using the color material layer coating liquid of one embodiment is determined by, for example, the following method. Is possible. First, the color material layer of the target thermal transfer sheet is analyzed to identify the color material component, binder resin component, and dispersant component contained in the color material layer. As a method for specifying these components, a conventionally known analysis method such as nuclear magnetic resonance spectroscopy or IR spectrum method can be used.

  Next, the type of the solvent remaining in the color material layer is 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, the back layer, or any layer of the target thermal transfer sheet, in specifying the type of solvent, the layer corresponding to the color material layer of the target thermal transfer sheet Need to be identified. Specifically, when the type of solvent is specified 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.

  At least one of the colorant components specified above is a colorant component that can be dissolved in the solvent specified above, and the specified binder resin component satisfies the above condition 3, When it is contained, it can be determined that the color material layer of the target thermal transfer sheet is formed using the color material layer coating liquid of one embodiment. Whether or not the specified color material component is soluble or dispersible in the specified solvent can be specified using the above-mentioned “Method for specifying dispersibility of color material in a predetermined solvent”.

(Coloring material layer coating liquid of the first embodiment)
The color material layer coating liquid of the first embodiment contains the predetermined solvent, color material, dispersant, and binder resin described in the color material layer coating liquid of the above one embodiment, and the above condition 1 -Coloring material layer coating liquid satisfying Condition 3 The color material layer coating liquid of the first embodiment is an embodiment that does not contain a sublimable dye that can be dissolved in a predetermined solvent, and is the color material layer coating liquid of the above one embodiment. What is necessary is just to read description as the coating material liquid for color material layers of 1st Embodiment as it is.

  According to the color material layer coating solution of the first embodiment, the color material 10x can be present in a finely divided state in the color material layer coating solution. As a result, a high-density image can be formed at the time of image formation using the thermal transfer sheet including the color material layer formed using the color material layer coating liquid of the first embodiment. Further, according to the color material layer coating liquid of the first embodiment, as shown in FIG. 1, the color material layer 2 in which the color material 10x is uniformly dispersed can be formed. In the thermal transfer sheet provided with the layer 2, it is possible to suppress the occurrence of kicks and soiling.

(Coloring material layer coating liquid of the second embodiment)
The color material layer coating liquid of the second embodiment contains the predetermined solvent, color material, dispersant, and binder resin described in the color material layer coating liquid of the above one embodiment, and the above condition 1 A coating material for a color material layer that satisfies the condition 3 and further contains a sublimable dye that can be dissolved in a predetermined solvent. The color material layer coating liquid of the second embodiment is only the above in that a sublimable dye that is soluble in a predetermined solvent is contained in the color material layer coating liquid of the first embodiment. It is different from the coating liquid for color material layer of the first embodiment. Hereinafter, the difference will be mainly described. Unless otherwise specified, each component contained in the color material layer coating liquid of the second embodiment can be used as it is described in the color material layer coating liquid of the above one embodiment, Detailed description is omitted.

  FIG. 2 is a schematic cross-sectional view of a thermal transfer sheet including a color material layer formed using the color material layer coating liquid according to the second embodiment, and a color material 10x dispersible in a predetermined solvent, and a predetermined color material. 1 schematically illustrates a sublimable dye that can be dissolved in a solvent.

  According to the color material layer coating solution of the second embodiment, the color material layer coating solution of the second embodiment is formed in the same manner as the color material layer coating solution of the first embodiment. In a thermal transfer sheet having a color material layer, it is possible to prevent the occurrence of kicks and background stains. Moreover, the color material 10x can be made to exist in the state atomized in the color material layer formed using the coating material for color material layers of 2nd Embodiment, and the thermal transfer provided with the said color material layer formed Using the sheet, high density image formation is possible. In addition, the color material layer formed using the color material layer coating liquid of the second embodiment contains a sublimable dye that is soluble in a predetermined solvent. A high density image can be formed by the synergistic effect of the material 10x and the sublimable dye that can be dissolved in a predetermined solvent. Particularly, when the printing energy is increased, the color material of the first embodiment Compared to a thermal transfer sheet provided with a color material layer formed using a layer coating solution, a color material layer capable of forming an image having a higher density can be obtained.

  A thermal transfer sheet comprising a color material layer 2 formed using the color material layer coating solution of the second embodiment is formed using the color material layer coating solution of the first embodiment. As in the case of the thermal transfer sheet provided with the above, although a detailed mechanism capable of preventing kicks and scumming has not been clarified at present, the color material 10x dispersible in a predetermined solvent is added to the predetermined solvent. The color material layer 2 that functions as a role to suppress localization of the dissolvable sublimable dye 10y to the interface of the color material layer 2 and is formed using the color material layer coating liquid of the second embodiment. In the thermal transfer sheet provided, it is presumed that the sublimable dye 10y can be present in the color material layer 2 in a dispersed state.

  The reason why the color material 10x functions as a role of suppressing localization to the interface of the sublimable dye 10y includes the affinity between the sublimable dye 10y and the color material 10x. As shown in FIG. 4, if the dye layer 2 </ b> A is formed using a “comparative dye layer coating solution” in which a sublimable dye 10 y is dissolved in a predetermined solvent, The sex dye 10y is localized toward the free interface. However, in the color material layer coating liquid of the second embodiment, since the color material 10x is dispersed, the color material layer of the second embodiment depends on the affinity between the color material 10x and the sublimable dye 10y. In the color material layer 2 formed using the coating liquid, it is speculated that the sublimable dye 10y can be present around the color material 10x existing in a dispersed state. As a result, as shown in FIG. 2, the localization of the sublimation dye 10y at the interface can be suppressed, and the sublimation dye 10y can be present in a state dispersed in the color material layer 2, thereby causing kicks and soiling. It is thought that the occurrence of this is prevented.

  Moreover, since the sublimation dye which can be melt | dissolved in the predetermined | prescribed solvent contains in the coating liquid for color material layers of 2nd Embodiment, using the coating liquid for color material layers of 2nd Embodiment. The sublimable dye 10y can be present at the molecular level in the colorant layer to be formed. Thereby, in a thermal transfer sheet provided with a color material layer formed using the color material layer coating liquid of the second embodiment, an image with a higher density can be formed. In particular, when the printing energy is increased, an image having a higher density can be formed as compared with the thermal transfer sheet including the color material layer formed using the color material layer coating liquid of the first embodiment. It becomes possible.

"Sublimation dyes that can be dissolved in a given solvent"
The sublimable dye that can be dissolved in a predetermined solvent is not particularly limited, and can be appropriately selected according to the type of the predetermined solvent contained in the color material layer coating liquid of the second embodiment. Specifically, any sublimable dye may be used as long as it is a sublimable dye that can be dissolved in the solvent contained in the color material layer coating liquid of the second embodiment. For example, according to the solvent contained in the color material layer coating solution of the second embodiment, the sublimation dye described in the color material layer coating solution of the above one embodiment may be appropriately selected and used. it can. Whether or not the sublimable dye contained in the color material layer coating liquid of the second embodiment is a sublimable dye that can be dissolved in a predetermined solvent is determined according to “predetermined” of the thermal transfer sheet of the one embodiment. It can be determined by “a method for specifying the dispersibility of a coloring material in a solvent”. Hereinafter, a case where the predetermined solvent is a mixed solvent of methyl ethyl ketone / toluene will be described as an example, and an example of a sublimable dye that can be dissolved in the predetermined solvent will be described.

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. Further, as described in the color material layer coating liquid of the above-described embodiment, examples of the color material that can be dispersed in a mixed solvent of methyl ethyl ketone / toluene include, for example, the pigments exemplified above and the sublimability exemplified above. Examples of the dye include Disperse Yellow 54.

  Similar to the color material layer coating liquid of the one embodiment, the color material layer coating liquid of the second embodiment may contain two or more solvents, but the color material of the second embodiment. The layer coating liquid contains a color material 10x that is dispersible in the two or more solvents, in other words, insoluble, and can be dissolved in at least one of the two or more solvents. It is an essential condition that the sublimable dye 10y is contained.

  There is no particular limitation on the content ratio of the sublimable dye 10y that can be dissolved in a predetermined solvent and the colorant 10x that can be dispersed in the predetermined solvent contained in the color material layer coating liquid of the second embodiment. It can be appropriately set according to functions required for the color material layer 2 formed using the color material layer coating liquid, such as light resistance and density characteristics.

<< Method for Manufacturing Sublimation Type Thermal Transfer Sheet >>
Next, the manufacturing method of the sublimation type thermal transfer sheet of one embodiment of the present invention will be described. The method for producing a sublimation type thermal transfer sheet according to one embodiment of the present invention (hereinafter sometimes referred to as the production method according to one embodiment) applies a color material layer coating liquid on one surface of a substrate. And a step of forming a color material layer. Hereinafter, the process of forming the color material layer, which is an essential process, and an optional process will be described.

<Step of forming a color material layer>
The manufacturing method of one embodiment includes a step of forming a color material layer 2 by applying a color material layer coating solution on one surface of the substrate 1. In the manufacturing method of one embodiment, the color material layer coating liquid used here is the color material layer coating liquid described in the color material layer coating liquid of the one embodiment, that is, the above-described conditions. It is characterized by being a coating material for a color material layer satisfying 1 to 3. More specifically, a predetermined solvent, a colorant dispersible in the predetermined solvent, a dispersant, and (i) a polyvinyl acetal resin having a number average molecular weight (Mn) of 40000 or less, or (ii) JIS K 6703 ( 1995) and a coating material for a color material layer containing a nitrocellulose resin having a viscosity symbol of L1 / 8 or less or H1 / 8 or less.

(Base material)
The base material used in this step 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. Examples of such a substrate include a polyethylene terephthalate film, a 1,4-polycyclohexylenedimethylene terephthalate film, a polyethylene naphthalate film, and a polyphenylene sulfide film having a thickness of about 0.5 μm to 50 μm, preferably about 1 μm to 10 μm. , 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 and the like. Furthermore, each of these materials can be used alone, but may be used as a laminate in combination with other materials.

  The base material may be subjected to an adhesion treatment on the surface on which the color material layer coating liquid is applied. By performing the adhesion treatment, adhesion between the base material and the color material layer or an arbitrary layer provided between the base material and the color material layer 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)
As the color material layer coating solution to be coated on one surface of the substrate, the color material layer coating solution described in the above embodiment can be used as it is, and a detailed description here. Is omitted. For example, the color material layer coating solution of the first embodiment may be used, or the color material layer coating solution of the second embodiment may be used.

There is also no particular limitation on the coating method of the coating liquid for the color material layer, and coating and drying on a substrate using a known means such as a gravure printing method, a screen printing method, a reverse roll coating method using a gravure plate, etc. By doing so, it can be formed. 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. A thermal transfer sheet (see FIGS. 1 and 2) in which a color material layer is provided on one surface of a base material is obtained by applying and drying the color material layer coating liquid.

  In addition, when the coating material for color material layers of the said 1st Embodiment is used as a coating material for color material layers of one Embodiment, the thermal transfer sheet shown in FIG. 1 can be obtained. In addition, when the color material layer coating solution of the second embodiment is used, the thermal transfer sheet shown in FIG. 2 can be obtained. In any form of the thermal transfer sheet, since the color material layer formed using the color material layer coating liquid according to one embodiment satisfying the above conditions 1 to 3 is provided, the occurrence of kick and background stains is suppressed. be able to. Further, since the color material 10x can be present in a fine particle state in the color material layer, a high-density image can be formed using a thermal transfer sheet including the formed color material layer.

<Step of forming a dye layer>
In addition, the manufacturing method according to an embodiment includes a dye layer coating solution obtained by dissolving a sublimable dye in a solvent before the step of forming the color material layer 2 on the substrate 1. The step of forming the dye layer 2A by coating and drying may be included. According to the manufacturing method of this embodiment, as shown in FIG. 3, a thermal transfer sheet in which a dye layer 2A and a color material layer 2 are laminated in this order on a substrate 1 can be obtained.

  According to the thermal transfer sheet of the form shown in FIG. 3, the color material layer 2 provided on the dye layer 2A functions as a lid that blocks the sublimation dye localized at the interface in the dye layer 2A. , Can prevent the occurrence of kicks and dirt. Specifically, as described above, a dye formed using a “coating liquid for comparative dye layer” containing a binder resin, a predetermined solvent, and a sublimable dye that can be dissolved in the predetermined solvent. In the comparative thermal transfer sheet provided with the layer 2A, the sublimable dye is present in a localized state at the interface (see FIG. 4), and it is in a situation where kicks and dirt are likely to occur. That is, when a thermal transfer sheet in which only the dye layer 2A is provided on the base material 1 is manufactured, it is not possible to prevent kicks and background stains.

  On the other hand, in the method for producing a sublimation type thermal transfer sheet of one embodiment, the color material layer 2 formed using the color material layer coating liquid of the one embodiment is provided on the dye layer 2A. Occurrence of kicks or background stains that cannot be compensated for by the dye layer 2A alone can be prevented by the color material layer 2 formed using the color material layer coating liquid of one embodiment. Moreover, in the manufacturing method of one Embodiment which has the process of forming dye layer 2A between a base material and a color material layer, between base material 1 and the color material layer 2, binder resin, a predetermined | prescribed solvent, and Since the dye layer 2A containing the sublimable dye 10y that can be dissolved in the predetermined solvent is provided, the synergistic effect of the dye layer 2A and the color material layer 2 enables image formation with higher density. Become.

  The binder resin contained in the dye layer coating solution is not particularly limited, and can be appropriately selected according to the type of the sublimable dye that can be dissolved in the solvent contained in the dye layer coating solution. . For example, the arbitrary binder resin demonstrated with the coating material for color material layers of one Embodiment, the binder resin which satisfy | fills the said conditions 3, etc. can be mentioned.

"Sublimation dye"
The sublimable dye 10y contained in the dye layer coating solution is not particularly limited, and can be appropriately selected depending on the solvent contained in the dye layer coating solution. Specifically, any sublimable dye that satisfies the condition that it can be dissolved in at least one solvent contained in the dye layer coating solution may be used. Examples of such sublimable dyes include “sublimable dyes that can be dissolved in a predetermined solvent” described in the coating material for a color material layer according to the second embodiment. The dye layer coating solution may contain two or more sublimable dyes that can be dissolved in a predetermined solvent.

  The solvent contained in the dye layer coating solution is not particularly limited as long as it can dissolve the sublimable dye, and can be appropriately selected from conventionally known solvents.

  The dye layer coating liquid may contain a colorant dispersible in all the solvents contained in the coating liquid. That is, the dye layer 2A can have the same configuration as the color material layer (see FIG. 2) formed using the color material layer coating liquid of the second embodiment.

The method for forming the dye layer 2A is not particularly limited, but it contains a binder resin, a solvent, a sublimation dye that can be dissolved in the solvent, and various components that are added as necessary, and the sublimation dye is dissolved in the solvent. A dye layer coating solution is prepared, and the coating solution is applied onto the substrate 1 using a known means such as a gravure printing method, a screen printing method, or a reverse roll coating method using a gravure plate. -It can be formed by drying. Although there is no particular limitation on the coating amount of the dye layer coating solution is preferably 0.1g / m ² ~5g / m ² approximately in solids.

  As long as the sublimation dye in the dye layer coating solution and the color material dissolution / dispersion conditions in the color material layer coating solution satisfy the above relationship, the solvent contained in the dye layer coating solution and The solvent contained in the color material layer coating solution may be a common residual solvent. In this case, it is a condition that the dye layer coating solution contains at least one sublimable dye that can be dissolved in the common solvent. In addition, the color material layer coating liquid is required to contain at least one color material that can be dispersed in a common solvent. Further, the sublimable dye contained in the dye layer coating liquid and the color material contained in the color material layer coating liquid may be the same color material. In this case, the dye layer coating liquid contains a solvent capable of dissolving the same color material, and the color material layer coating liquid contains a solvent capable of dispersing the same color material. As a condition.

(Step of forming the dye primer layer)
In one embodiment, the dye primer layer is formed by applying and drying a dye primer layer coating solution between the substrate 1 and the colorant layer 2 or between the substrate 1 and the dye layer 2A. A step of forming may be included. According to the manufacturing method of one embodiment including this step, the adhesion between the base material 1 and the color material layer 2 or the base material 1 and the dye layer 2A is improved, and the color material layer 2 or the dye layer is formed during image formation. It is possible to prevent 2A from being abnormally transferred.

  The dye primer layer coating solution contains a solvent and a binder resin. As binder resins, polyester resins, polyvinyl pyrrolidone resins, polyvinyl alcohol resins, hydroxyethyl cellulose, polyacrylate resins, polyvinyl acetate resins, polyurethane resins, styrene acrylate resins, polyacrylamide 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, pseudo boehmite, etc.), aluminum silicate, magnesium silicate, magnesium carbonate, magnesium oxide, Examples include titanium oxide. 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 for the gravure coating method, roll coating method, screen printing method, 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. Examples of the solvent used for preparing the dye primer layer coating solution include water, toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methanol, ethanol, isopropyl alcohol, dimethylformamide, ethyl acetate, butyl acetate, and ethylene glycol. Dimethylacetamide, dimethyl sulfoxide and the like.

<Step of forming the back layer>
Moreover, the manufacturing method of one embodiment may include a step of forming the back layer 5 by applying and drying a back layer coating solution on the other surface of the substrate 1.

  The back layer coating solution contains a solvent and a binder resin. The binder resin contained in the back layer coating liquid is not particularly limited, and can be formed by appropriately selecting a conventionally known thermoplastic resin or the like. 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, the coating liquid for back layers may contain the lubricant for improving the slidability with a thermal head. 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. Among these, 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.

There is no particular limitation on the method of forming the back layer, and a back layer coating solution in which a binder resin, a lubricant added as necessary is dissolved or dispersed in an appropriate solvent, a gravure printing method, a screen printing method, a gravure plate It can be formed by coating on the other surface of the substrate 1 using a known coating means such as a reverse roll coating method using, and drying. As the solvent used for the preparation of the coating solution for the back layer, the solvents described in the above-mentioned dye primer layer coating solution can be appropriately selected and used. The coating amount of the back layer coating solution, from the viewpoint of improvement of heat resistance and the ^{like, 0.1g / m 2 ~5g / m} 2 about ^{preferably, 0.3g / m 2 ~2.0g / m} 2 The degree is more preferred.

<Step of forming the back primer layer>
In addition, the manufacturing method according to an embodiment may include a step of forming a back primer layer between the base material 1 and the back layer 5. According to the manufacturing method of one embodiment including this step, the adhesion between the base material and the back layer can be improved.

  The coating solution for the back primer layer contains a solvent and a binder resin. Examples of the binder resin 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, and polyvinylpyrrolidone resin. Is mentioned. Moreover, you may contain the electrically conductive material for providing electroconductivity suitably. Examples of the conductive material include sulfonated polyaniline, carbon particles, silver particles, and gold particles.

  As mentioned above, although the manufacturing method of the thermal transfer sheet of this invention was concretely demonstrated giving an example, various deformation | transformation aspects can be taken in the range which does not disturb the meaning of this invention. For example, in the configuration shown in FIGS. 1 to 3, the base material 1 is formed as an integrated thermal transfer sheet in which a color material layer 2 and a transferable protective layer (not shown) are provided in the surface order on the same surface of the base material 1. A step of forming a transferable protective layer by applying a coating solution for the transferable protective layer on one surface of the film may be included. In addition, the thermal transfer sheet obtained by the production method of the present invention may be one in which a yellow color material layer, a magenta color material layer, and a cyan color material layer are provided in the surface order on the substrate 1. In this case, at least one of the color material layers provided in the surface order may be formed using the color material layer coating liquid of the present invention described above. Moreover, all the color material layers may be formed using the color material layer coating solution of the present invention.

  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
A 4.5 μm thick polyethylene terephthalate film with an easy adhesion treatment is used as the base material, and a coating solution for the back layer having the following composition is applied to one surface of the base material with a coating amount of 0.0 in terms of solid content. The back layer was formed by applying and drying at 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, “Disperse Yellow 54” was determined to be a colorant that can be dispersed 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”. Further, “Disperse Yellow 201” and the color material (dye) represented by the following general formula (4) were determined to be color materials (dye) dispersible in a toluene / methyl ethyl ketone mixed solvent.

<Back layer coating liquid>
・ 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 coating material 1 for the color material layer below, the color material, the dispersant, the binder resin, the polyethylene wax, the solvent, and 250 parts by mass of zirconia beads having a particle size of 2.0 mm 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, put 250 parts by weight of zirconia beads having a particle size of 0.1 mm into a glass bottle, and similarly paint crusher as the main crushing Was dispersed for 24 hours to prepare a coating material 1 for a color material layer.

<Coloring material layer coating solution 1>
Disperse Yellow 54 4.725 parts Pigment represented by the following general formula (3) 0.525 parts (sulfonated derivative of CI Pigment Yellow 138)
・ Graft type polymer dispersant (Mw: 40000 to 50000) 1.5 parts (Ajisper PB881, Ajinomoto Fine Techno Co., Ltd.)
-Polyvinyl acetoacetal resin (Mn: 27000) 4.5 parts (KS-1 Sekisui Chemical Co., Ltd.)
・ Toluene 44.375 parts ・ Methyl ethyl ketone 44.375 parts

(Example 2)
Instead of the coating solution 1 for the color material layer, 4.5 parts of the polyvinyl acetoacetal resin (Mn: 27000) (KS-1 Sekisui Chemical Co., Ltd.) of the coating solution 1 for the color material layer is replaced with polyvinyl acetoacetal. Resin (Mn: 17000) (KS-10 Sekisui Chemical Co., Ltd.) Except for using the coating material 2 for colorant layer changed to 4.5 parts, the same as in Example 1 was repeated. A thermal transfer sheet was obtained.

(Example 3)
Instead of the coating solution 1 for the color material layer, 4.5 parts of the polyvinyl acetoacetal resin (Mn: 27000) (KS-1 Sekisui Chemical Co., Ltd.) of the coating solution 1 for the color material layer is replaced with polyvinyl acetoacetal. Resin (Mn: 20000) (BX-L Sekisui Chemical Co., Ltd.) The same procedure as in Example 1 was conducted except that the coating material 3 for colorant layer was changed to 4.5 parts. A thermal transfer sheet was obtained.

Example 4
Instead of the coloring material layer coating solution 1, 4.5 parts of the polyvinyl acetoacetal resin (Mn: 27000) (KS-1 Sekisui Chemical Co., Ltd.) of the coloring material layer coating solution 1 is added to the nitrocellulose resin. (DLX5-8 (L1 / 8 equivalent) Inabata Sangyo Co., Ltd.) Thermal transfer of Example 4 in the same manner as in Example 1 except that the coating material 4 for color material layer changed to 4.5 parts was used. A sheet was obtained.

(Example 5)
Instead of the coloring material layer coating solution 1, 4.5 parts of the polyvinyl acetoacetal resin (Mn: 27000) (KS-1 Sekisui Chemical Co., Ltd.) of the coloring material layer coating solution 1 is added to the nitrocellulose resin. (DHX5-10 (L1 / 8 equivalent) Inabata Sangyo Co., Ltd.) Thermal transfer of Example 5 in the same manner as in Example 1 except that the coating material 5 for color material layer changed to 4.5 parts was used. A sheet was obtained.

(Example 6)
Instead of the coloring material layer coating solution 1, 4.5 parts of the polyvinyl acetoacetal resin (Mn: 27000) (KS-1 Sekisui Chemical Co., Ltd.) of the coloring material layer coating solution 1 is added to the nitrocellulose resin. (DHX4-6 (equivalent to L1 / 16) Inabata Sangyo Co., Ltd.) Thermal transfer of Example 6 in the same manner as Example 1 except that the coating material 6 for color material layer changed to 4.5 parts was used. A sheet was obtained.

(Example 7)
A thermal transfer sheet of Example 7 was obtained in the same manner as in Example 1 except that the color material layer coating solution 1 having the following composition was used instead of the color material layer coating solution 1 of Example 1. . The color material layer coating solution 7 was prepared in the same manner as the color material layer coating solution 1.

<Coloring material layer coating solution 7>
Disperse Yellow 201 2.3625 parts Disperse Yellow 54 2.3625 parts Pigment represented by the following general formula (3) 0.525 parts (sulfonated derivative of CI Pigment Yellow 138)
・ Graft type polymer dispersant (Mw: 40000 to 50000) 1.5 parts (Ajisper PB881, Ajinomoto Fine Techno Co., Ltd.)
-Polyvinyl acetoacetal resin (Mn: 27000) 4.5 parts (KS-1 Sekisui Chemical Co., Ltd.)
・ Toluene 44.375 parts ・ Methyl ethyl ketone 44.375 parts

(Example 8)
The dye layer coating liquid 1 prepared by the following method is applied onto the dye primer layer so that the coating amount is 0.5 g / m ^{2 in} terms of solid content, and dried to form a dye layer. Then, on the dye layer, the color material layer coating liquid 1 having the above composition is applied so that the coating amount is 0.5 g / m ^{2 in} terms of solid content, and is dried. A thermal transfer sheet of Example 8 in which a color material layer was laminated on the dye layer was obtained in the same manner as in Example 1 except that was formed.

(Preparation of dye layer coating solution 1)
As shown in the composition of Dye Layer Coating Liquid 1 below, color material, binder resin, polyethylene wax and solvent are placed in a glass bottle, sealed, heated at 50 ° C. for 1 hour, and then 30 minutes on a paint shaker (manufactured by Asada Tekkosha). Shake to prepare a dye layer coating solution 1.

<Dye layer coating solution 1>
Disperse Yellow 201 3.51 parts Polyvinyl acetoacetal resin (Mn: 130000) 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

Example 9
Instead of the color material layer coating liquid 1, disperse yellow 201 (2.3625 parts) of the color material layer coating liquid 7 is replaced with a sublimable dye (2.3625 parts) represented by the following general formula (4). The thermal transfer sheet of Example 9 was obtained in the same manner as in Example 1 except that the color material layer coating solution 8 changed to (1) was used.

(Comparative Example 1)
A thermal transfer sheet of Comparative Example 1 was obtained in the same manner as in Example 1 except that the dye layer coating solution 1 was used instead of the coloring material layer coating solution 1.

(Comparative Example 2)
Instead of the coating solution 1 for the color material layer, 4.5 parts of the polyvinyl acetoacetal resin (Mn: 27000) (KS-1 Sekisui Chemical Co., Ltd.) of the coating solution 1 for the color material layer is replaced with polyvinyl acetoacetal. Resin (Mn: 130000) (KS-5 Sekisui Chemical Co., Ltd.) The same as Example 1 except that the coating material A for colorant layer changed to 4.5 parts was used. A thermal transfer sheet was obtained.

(Comparative Example 3)
Instead of the coloring material layer coating solution 1, 4.5 parts of the polyvinyl acetoacetal resin (Mn: 27000) (KS-1 Sekisui Chemical Co., Ltd.) of the coloring material layer coating solution 1 is added to the nitrocellulose resin. (DLX8-13 (equivalent to L1 / 4) Inabata Sangyo Co., Ltd.) Thermal transfer of Comparative Example 3 in the same manner as in Example 1 except that the coating material B for colorant layer changed to 4.5 parts was used. A sheet was obtained.

(Comparative Example 4)
Instead of the coating solution 1 for the color material layer, 4.5 parts of the polyvinyl acetoacetal resin (Mn: 27000) (KS-1 Sekisui Chemical Co., Ltd.) of the coating solution 1 for the color material layer is added to cellulose acetate Except for using the colorant layer coating liquid C changed to 4.5 parts of a pioneate resin (Mn: 25000) (CAP482-0.5 Eastman Chemical Co., Ltd.), A thermal transfer sheet of Comparative Example 4 was obtained.

(Volume average particle diameter of coloring material)
The volume of the color material dispersed in the color material layer coating liquids 1 to 7 and the color material layer coating liquids A to C for forming the thermal transfer sheets of Examples and Comparative Examples prepared above. The average particle size (nm) was measured by the particle size measurement method using the laser light scattering particle size distribution meter described above. The measurement results are shown in Table 1. In the dye layer coating solution 1, the particle size cannot be measured because the sublimable dye (disperse yellow 201) is dissolved in the coating solution.

(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 2.05 or more.
○: The concentration is 1.95 or more and less than 2.05.
(Triangle | delta): A density | concentration is less than 1.95.

(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 liquid 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 of the back layer was evaluated. For the evaluation of the contamination property, the color material layer surface and the back layer surface of the thermal transfer sheets of each Example and Comparative Example were overlapped, and a load of 20 kg / cm ² was applied and stored in an environment of 40 ° C. and 90% RH for 98 hours. The migration of the color material to the back layer surface was evaluated. The evaluation of migration is performed by measuring the back layer surface before and after storage with a spectrophotometer (Spectaglino manufactured by Gretag Macbeth Co., Ltd.) and obtaining the color difference (ΔE ^{* ab} ) by the following formula, based on the following evaluation criteria. Contamination was evaluated. The evaluation results are also shown in Table 1. In addition, the same back layer produced with the thermal transfer sheet of each said Example and a comparative example was used for the back layer overlapped with the color material layer of the thermal 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.

DESCRIPTION OF SYMBOLS 1 ... Base material 2 ... Color material layer 2A ... Dye layer 5 ... Back surface layer 10x ... Color material 10y dispersible in a predetermined solvent ... Sublimation soluble in a predetermined solvent Dye 100 ... thermal transfer sheet 100X manufactured using the colorant layer coating liquid of one embodiment of the present invention ... thermal transfer sheet manufactured using the comparative dye layer coating liquid

Claims (5)

A color material layer coating solution for forming a color material layer of a sublimation thermal transfer sheet,
Contains a predetermined solvent, coloring material, dispersant, and binder resin,
The color material is a color material dispersible in the predetermined solvent,
The binder resin is (i) a polyvinyl acetal resin having a number average molecular weight (Mn) of 40000 or less, or (ii) a nitro compound having a type and viscosity symbol in JIS K 6703 (1995) of L1 / 8 or less, or H1 / 8 or less. A coating material for a color material layer, which is a cellulose resin. The color material layer coating liquid contains a color material represented by the following general formula (1) and the following general formula (2) as a color material dispersible in the predetermined solvent. The colorant layer coating solution according to claim 1.

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.

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.   The color material layer coating liquid contains one or more selected from the group of polyether dispersants, graft polymer dispersants, and acrylic block polymer dispersants as the dispersant. The color material layer coating solution according to claim 1, wherein the color material layer coating solution is provided.   The color material layer coating solution according to any one of claims 1 to 3, wherein the color material layer coating liquid further contains a sublimable dye that is soluble in the predetermined solvent. Engineering liquid. A method for producing a sublimation thermal transfer sheet,
Including a step of coating the color material layer coating liquid on one surface of the substrate to form a color material layer,
The color material layer coating liquid contains a predetermined solvent, a color material dispersible in the predetermined solvent, a dispersant, and a binder resin.
The binder resin contained in the color material layer coating liquid is (i) a polyvinyl acetal resin having a number average molecular weight (Mn) of 40000 or less, or (ii) a type and viscosity symbol in JIS K 6703 (1995). A method for producing a sublimation thermal transfer sheet, characterized in that the nitrocellulose resin is 8 or less or H1 / 8 or less.

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