JPH10305665A - Thermal transfer sheet and thermal transfer recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermal transfer record having excellent light resistance and high density. SOLUTION: The thermal transfer sheet comprises at least a plurality of coloring material layers arranged in surface sequence provided on one surface of a base material, wherein at least one layer among them contains indophenol cyan dye, and at least other one layer contains bispyrazolonemethine yellow dye. The sheet is used for a sublimable thermal transfer recording system having a protective layer provided on a surface of a transfer image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer sheet used for a color hard copy by a so-called thermal transfer recording system. In particular, the present invention relates to a heat-sensitive transfer sheet, which is used in a method of providing a protective layer on a transferred image among transfer sheets used in a sublimation transfer recording method, and can impart excellent light resistance to an image.

[0002]

2. Description of the Related Art In recent years, techniques for converting a color image based on an electric signal such as a video image into a color hard copy have been advanced, and for example, methods such as electrophotography, ink jet, and thermal transfer have been studied. Among them, the thermal transfer method is particularly advantageous from the viewpoints of easy maintenance and operation of the apparatus, miniaturization of the apparatus, and the like. In the thermal transfer method, the coloring material layer on the substrate is melted by heating,
There are known a fusion transfer method in which the dye is transferred to a recording material, and a so-called sublimation transfer method in which only the dye in the color material layer is transferred to the recording material. In the sublimation transfer method, since the amount of the dye to be transferred can be controlled by the degree of heating, expression with density gradation can be performed, and fine print or an image equivalent to a photograph can be obtained. Normal color print is
A heat-sensitive transfer sheet which is expressed by three primary colors of yellow, magenta and cyan and is used in a sublimation transfer system also usually has three color material layers of yellow, magenta and cyan sequentially arranged on a substrate.

[0003] By utilizing the feature of obtaining an image equivalent to a photograph of the sublimation transfer system, it has come to be used, for example, for producing ID cards such as identification cards. However, there is a problem that the formed image is inferior in durability such as light resistance, weather resistance and friction resistance, and as a method for solving the problem, a method of forming a transparent protective layer on the image has been proposed. . For example, JP-A-60-23096, JP-A-4-241
No. 991 can be cited. As a method of forming a protective layer on an image, a method of applying a protective layer to the surface after image formation, a method of laminating, or forming a heat transferable protective layer on a heat-sensitive transfer sheet in the order of a color material layer and a surface layer. A method has been proposed in which an image is formed on an image receiving sheet and then the protective layer is thermally transferred.

[0004]

Heretofore, when an image formed by the sublimation transfer method is used for an ID card or the like, sufficient light resistance cannot be obtained even if a protective layer is formed on the surface. In order to improve the light fastness, a device has been proposed in which a protective layer is provided with an ultraviolet absorber by adding an ultraviolet absorber or the like, but it is difficult to obtain sufficient light fastness even with these means. . Further, it was difficult to obtain a recorded image having good light resistance and high density. this is,
Transfer density is high and there are few dyes with good lightfastness.
Furthermore, it was found that depending on the combination of dyes, there was a catalytic fade phenomenon in which photobleaching proceeded remarkably. This is particularly remarkable in a combination of a cyan dye and a yellow dye, and it has been found that this is likely to occur with an indophenol dye which is a powerful cyan dye. Depending on the yellow pigment used in combination, when exposed to light, the combined use of the indophenol-based pigments will greatly discolor. As a result, there was no dye among the commonly used yellow dyes for thermal transfer recording that provided high density, had good light fastness, and did not cause catalytic fade in combination with indophenol dyes. . For this reason, it was difficult to obtain high-density recording with good light fastness in mixed green (yellow + cyan) and black (yellow + magenta + cyan).

The problem with lightfastness of these dyes is that
It was thought that this would be solved by providing a protective layer and having the ability to absorb ultraviolet light. However, in practice, even if the protective layer is provided with an ultraviolet absorbing ability to improve the light resistance alone, the catalytic fade phenomenon could not be prevented, and the light resistance problem was not solved. This is because the catalytic fade phenomenon has a different mechanism from the fading caused by ordinary light. Normal light fading is a phenomenon in which a dye is directly or indirectly decomposed by strong light energy such as ultraviolet light, while a catalytic fade phenomenon is an energy transition from a dye molecule excited by absorbing light to another dye molecule. It is said to be caused by. In order to prevent the excitation of the dye molecules, it is necessary to block the visible light. This means that the protective layer absorbs the visible light in the present invention, so that the image is hidden. Since the state of expression of the catalytic fade phenomenon differs depending on the combination of dyes, a good combination can be known by a person who recognizes this problem through actual experiments.

[0006]

That is, the gist of the present invention is to provide a heat-sensitive transfer sheet used in a sublimation heat-sensitive transfer recording system in which a protective layer is provided on the surface of a transfer image, wherein at least a plurality of heat transfer sheets are provided on one surface of a substrate. A color material layer is provided in a face-sequential manner, at least one color material layer contains an indophenol cyan dye, and at least one other color material layer contains a bispyrazolone methine yellow dye. A heat-sensitive transfer sheet. Bispyrazolone methine dyes are a group of dyes having a structure in which two pyrazolone rings are crosslinked by a methine bond.

Another gist of the present invention is to use a thermal transfer sheet for thermal transfer recording, in which a color material layer is provided on at least one surface of a substrate, to obtain an image on an image receiving sheet, and A sublimation thermal transfer recording method in which a protective layer is provided on the surface, wherein a bispyrazolone methine yellow dye is used as a yellow dye, and an indophenol cyan dye is used as a cyan dye. An image is formed on an intermediate recording layer using a thermal transfer sheet for thermal transfer recording in which a color material layer is provided on at least one surface of the material, and then the intermediate recording layer is thermally transferred to the surface of the final recording material. In the sublimation thermal transfer recording method for obtaining a recorded image having a protective layer formed thereon, a bispyrazolone methine dye is used as a yellow dye, and an indopheno dye is used as a cyan dye. Resides in the heat-sensitive transfer recording method characterized by Le cyan dye is used.

As a result of the study, the present inventor has found that a combination of an indophenol cyan dye and a bispyrazolone methine yellow dye is added to a color material layer of a thermal transfer sheet used for a thermal transfer recording system in which a protective layer is provided on the surface of a transferred image. It has been found that the use of No. 1 achieves a high transfer density and enables heat-sensitive transfer recording with high light resistance. With regard to light fastness, the effect is remarkable especially in green and black in which yellow and cyan are mixed, and particularly in green in which yellow and cyan are mixed. This is because the bispyrazolone methine yellow dye of the present invention is not only a dye capable of high density transfer, but also in combination with an indophenol cyan dye,
This is because it has been found that fading due to the catalytic fade phenomenon does not occur in the indophenol cyan dye. As a result, it is possible to suppress the catastrophic fade phenomenon that could not be solved even if the protective layer was provided and the protective layer had ultraviolet absorbing capability, and it was possible to achieve high light density and high density recording. Was.

Hereinafter, the present invention will be described in detail. The heat-sensitive transfer sheet according to the present invention includes a base material and a color material layer provided on at least one surface thereof. Generally, a heat-resistant lubricating layer is provided on one side of the substrate, usually on the opposite side of the colorant layer. As the substrate, a thin film is used, and examples thereof include a polyethylene terephthalate film, a polyamide film, a polyaramid film, a polyimide film, a polycarbonate film, a polyphenylene sulfide film, a polysulfone film, a cellophane, a triacetate film, and a polypropylene film. Among them, polyethylene terephthalate film
It is preferable in terms of mechanical strength, dimensional stability, heat resistance, price, and the like, and biaxially stretched polyethylene terephthalate film is particularly preferable. The thickness of these substrates is usually 1 to 3.
0 μm, preferably 2 to 10 μm.

In order to improve the adhesion to the colorant layer, the surface of the base film may be subjected to a corona treatment, or a polyester resin, a cellulose resin,
An anchor coat made of a polyvinyl alcohol-based resin, a urethane resin, a polyvinylidene chloride-based resin, or the like may be provided. The color material layer has a pigment and a binder resin as main components, and generally has at least three primary color material layers of yellow, magenta, and cyan in a plane-sequential manner. For printing, it usually has four color material layers to which black is added in a plane-sequential manner. The present application is characterized in that at least one of the coloring material layers contains an indophenol dye and at least one of the other coloring material layers contains a bispyrazolone methine dye. As the indophenol dye and the bispyrazolone methine dye, any one may be used as long as it meets the purpose of the present invention, and a plurality of dyes may be used in combination. In particular, a combination of an indophenol dye represented by the following general formula (1) and a bispyrazolone methine dye represented by the following general formula (2) is more preferable.

[0011]

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[0012]

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In the substituent of the indophenol-based dye represented by the general formula (1), "lower" means having 1 to 8 carbon atoms. As the aryl group and the aralkyl group, those having 6 to 10 carbon atoms are usually used. In the general formula (1), -A- represents -CO- or -COO-, R ₁ represents an alkyl group which may be substituted, an optionally substituted lower alkenyl group, optionally substituted aryl Represents an optionally substituted aralkyl group or an alkyl group or a heterocyclic ring optionally substituted by a halogen atom, R ₂ and R ₃ represent an optionally substituted alkyl group, and R ₄ represents methyl It represents a group or an ethyl group, R ₅
Represents a hydrogen atom or a methyl group, and X represents a hydrogen atom or a halogen atom.

Preferably, R ₁ is substituted by an alkyl group, a lower alkenyl group, an aralkyl group, an aryl group, a halogeno lower alkyl group, a hydroxy lower alkyl group, a cyano lower alkyl group, an alkyl group having an ether bond, or a heterocyclic ring. R ₂ represents a lower alkyl group, R ₃ represents a lower alkyl group, a halogeno lower alkyl group, a hydroxy lower alkyl group, an amino lower alkyl group, an alkyl group having an ether bond, and an amide bond. Represents an alkyl group or an alkyl group having a sulfonylamino bond, R ₄ represents a methyl group or an ethyl group, R ₅ represents a hydrogen atom or a methyl group, and X represents a hydrogen atom, a chlorine atom, or a bromine atom.

More preferably, R ₁ is a lower alkyl group,
Lower alkenyl group, aralkyl group having 7 to 10 carbon atoms, aryl group having 6 to 10 carbon atoms, chloroethyl group, lower alkoxyalkyl group, tetrahydrofurfuryl group, aralkyloxyethyl group having 9 to 12 carbon atoms, 8 to carbon atoms 12
Represents an aryloxyethyl group, a lower alkenyloxyethyl group, or a heterocyclic ring containing O, N or S as a hetero atom, R ₂ represents a methyl group or an ethyl group,
R ₃ represents a lower alkyl group, a chloroethyl group, a hydroxyethyl group, a lower alkoxyethyl group, an aralkyloxyethyl group having 9 to 12 carbon atoms, or an aryloxyethyl group having 8 to 12 carbon atoms, and R ₄ represents a methyl group or an ethyl group. R ₅ represents a hydrogen atom or a methyl group, and X represents a hydrogen atom or a chlorine atom. More preferably, R ₁ represents a lower alkyl group, a lower alkenyl group, a phenyl group, a toluyl group, a benzyl group, a tetrahydrofurfuryl group, a lower alkoxy lower alkyl group, furan, pyridine, thiophene, and R ₂ and R ₃ represent ethyl. R ₄ represents a methyl group or an ethyl group; R ₅ represents a hydrogen atom or a methyl group; and X represents a hydrogen atom or a chlorine atom. When X is a chlorine atom, it is preferable that R ₁ has 2 or more carbon atoms because the solubility of the dye is improved.

In the substituents of the bispyrazolone methine dye represented by the general formula (2), lower means one having 1 to 8 carbon atoms. Preferably, R ₆ and R ₇ represent an optionally substituted lower alkyl group, an optionally substituted lower alkenyl group, an optionally substituted aryl group,
R ₈ and R ₉ each represent an optionally substituted lower alkyl group, a dialkylamino group, a —COOY group, or a —CONZW group, and Y represents an optionally substituted lower alkyl group or an optionally substituted lower alkenyl group; And Z and W represent a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted lower alkenyl group, and an optionally substituted lower aryl group. Represent. More preferably, R ₆ and R ₇ represent a lower alkyl group, an optionally substituted aryl group, or an aralkyl group,
R ₈ and R ₉ represent a lower alkyl group or a —COOY group;
Is a lower alkyl group, an optionally substituted aryl group,
Represents an aralkyl group.

More preferably, R ₆ and R ₇ represent a lower alkyl group, a phenyl group or a benzyl group which may be substituted with a methyl group or a halogen atom, and R ₈ and R ₉ represent a lower alkyl group or a —COOY group. And Y represents a lower alkyl group, a methyl group or a phenyl group or a benzyl group which may be substituted with a halogen atom. Most preferred combinations of indophenol dyes and bispyrazolone methine-based dye, in indophenol dye represented by the general formula (1), -A- represents -CO- or -COO-, R ₁ is methyl Group, ethyl group, propyl group, butyl group, pentyl group, benzyl group, lower alkoxyethyl group, furan, R ₂ and R ₃ represent an ethyl group,
₄ represents a methyl group or an ethyl group; R ₅ represents a hydrogen atom or a methyl group; X represents a hydrogen atom or a chlorine atom; and a bispyrazolone methine dye represented by the general formula (2): ₆ , R ₇ represents a methyl group, an ethyl group, a propyl group, a butyl group, a phenyl group, a toluyl group,
R ₈ and R ₉ are a combination with a dye representing a methyl group, an ethoxycarbonyl group, or a butoxycarbonyl group.

Some of the indophenol dyes of the present invention represented by the general formula (1) have already been disclosed in JP-A-61-31292.
It is known from JP-A-61-35994 and the like to use for thermal transfer. The bispyrazolone methine dye represented by the general formula (2) is a known compound, but is not known to be used for thermal transfer. The present invention seeks to obtain better results by simultaneously using these dyes while making the best use of their properties. The main component other than the pigment in the color material layer is a binder resin. As the binder resin in this case, polycarbonate resin, polysulfone resin, polyvinyl butyral resin, phenoxy resin, polyarylate resin, polyamide resin, polyaramid resin, polyimide resin, polyetherimide resin, polyester resin, acrylonitrile styrene resin and acetyl cellulose, Cellulose-based resins such as methylcellulose, ethylcellulose and the like are exemplified. The coloring material layer is usually formed by applying and drying an ink obtained by dissolving or dispersing a dye and a binder resin in a solvent on a substrate.

Solvents used in the ink include aromatic solvents such as toluene and xylene; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ester solvents such as ethyl acetate and butyl acetate; isopropanol, butanol; Examples include alcohol solvents such as methyl cellosolve; ether solvents such as dioxane and tetrahydrofuran; amide solvents such as dimethylformamide and N-methylpyrrolidone. In the above ink, in addition to the above components, if necessary, organic or inorganic non-sublimable particles, dispersants, antistatic agents, antiblocking agents, defoamers, antioxidants, viscosity modifiers and the like Additives can be added. Further, an infrared absorbing agent or carbon black can be added for use in a sublimation transfer system using laser light. There is no particular limitation on the method of applying these inks to form a color material layer, but for example, gravure coat, gravure reverse coat, roll coat, and the like can be used. Association edited and published, 1978). The coating film thickness is 0.1 to
5 μm is suitable, more preferably 0.5 to 2 μm
It is.

Generally, the higher the ratio of the dye in the binder resin, the higher the transfer sensitivity and the highest attainable density, and the lower the ratio of the dye, the lower the sensitivity and the attainable density. However, when the ratio of the dye becomes extremely high, the dye precipitates out of the binder under high temperature, high humidity, or long-term storage, which adversely affects a transferred image. Therefore, in consideration of the storage stability and transferability of the heat-sensitive transfer sheet, the mixing ratio of the binder and the dye is suitably in the range of 1: 2 to 2: 1 by weight, and more preferably 1: 1. 0.5-1.
5: 1, more preferably 1: 1 to 1.
The range is 5: 1. In consideration of these points, it is preferable to use a binder resin having higher compatibility with the dye and having no problem even if the dye is contained at a high concentration, and among the binder resins described above, Tg of 50 ° C. or higher. A polycarbonate resin, a polysulfone resin, a phenoxy resin, a polyester resin, and an acrylonitrile styrene resin (AS resin) are preferred.

If necessary, a heat-resistant layer may be provided on the surface of the heat-sensitive transfer sheet opposite to the color material layer. Although there is no particular limitation on the heat-resistant layer, for example, those using a cured resin such as an ultraviolet-curable resin and those using a thermoplastic resin having a high Tg are known. Since the heat-resistant layer needs to have heat-sliding properties with respect to the thermal head in addition to the heat resistance of the thermal head, a lubricant such as silicone oil is generally added. To perform thermal transfer recording, the color material surface of the thermal transfer sheet and the image receiving surface of the image receiving sheet provided with an image receiving layer on one side of the substrate are superimposed so as to face each other,
Generally, heat is applied in accordance with an image signal from a heat source such as a line type thermal head from the side opposite to the color material surface of the thermal transfer sheet to transfer the dye in the color material layer to the image receiving layer. . At that time, the amount of the dye to be transferred can be changed according to the amount of heat applied, so that it is possible to express light and shade and obtain a fine image. By repeating the same operation for three colors of yellow, magenta, and cyan, or four colors including black, a photographic image can be obtained.

As a thermal transfer sheet for obtaining an image, there are a case where a thermal transfer sheet of each color is used and a case where a surface-sequential thermal transfer sheet is used. Is preferable because only one heat-sensitive transfer sheet is required to obtain an image, and the apparatus for performing the transfer is simplified. In the magenta coloring material layer, an anthraquinone dye, an imidazole azo dye, or a thiadiazole azo dye can be suitably used as a magenta dye. These were found not to be involved in the catalytic fade phenomenon. As the yellow dye, a dye other than bispyrazolone methine can be used in combination. However, the combined use with a dye that causes catalytic fade reduces the characteristics of the predominant bispyrazolone methine dye, so that the amount of the combined use is preferably small.

As the cyan dye, a dye other than the indophenol-based dye can be used in combination. For example, anthraquinone-based cyan dyes and monoazo-based cyan dyes can be used, but even though the catalytic fade phenomenon is unlikely to occur, it has been found that the light resistance of itself is insufficient or the sensitivity is insufficient. The smaller the combined amount, the better. As a heat source for transferring the dye, a line type thermal head is generally used, but it is also known to use a laser beam. In that case, it is necessary to use a light-to-heat conversion material for converting the laser light into heat, and an infrared absorber or carbon black is used between the color material layer and the base material in the color material layer of the thermal transfer sheet. Alternatively, it is known to be added to the surface opposite to the color material layer.

The protective layer of the present invention is used for protecting an image from contamination of the image by oil, water, dust and the like of a finger, decomposition of a dye by moisture, air, etc., and damage of the image due to mechanical shock and the like. Provided above. Although it can be provided by coating on the image, it is preferably provided so as to be thermally transferable on the substrate. In that case, the protective layer can be provided on the image by heating from the side opposite to the protective layer of the substrate. It may be a sheet in which only a protective layer is provided on a base material, or a sheet in which a color material layer and a protective layer are provided on a base material sequentially. The latter case is simple and preferable because a protective layer can be formed on an image with the same heat source continuously after image formation.

Hereinafter, the case where the protective layer is provided on the base material so as to be capable of thermal transfer will be described, but the usage is not limited thereto. As the base material on which the protective layer is provided, the same material as the base material used for providing the color material layer can be used. A release adjusting layer for adjusting the releasability of the protective layer may be provided on the surface on which the protective layer is provided. The protective layer preferably has a structure having at least two layers of a surface layer and an adhesive layer from the substrate side. A heat-resistant layer can be provided on the surface of the substrate opposite to the protective layer. The surface layer is made of various resins having excellent friction resistance, weather resistance, etc., for example, acrylic resin, polyurethane resin, polystyrene resin, polyester resin, acrylic urethane resin, silicone-modified resin of these resins, and a mixture of these resins. Is mainly contained. Among these resins, acrylic resins are preferred.

Since these resins form a tough film, the edges of the resin are likely to be insufficiently cut at the time of transfer from the opposite surface of the substrate. In order to improve this, fine particles such as silica or wax can be added to the surface layer. As a method of forming a surface layer on a substrate, a method similar to the method described in the case of forming a color material layer can be used. The thickness of the surface layer is preferably 0.1 to 10 μm.
m, preferably about 1 to 5 μm. For the purpose of improving light resistance and weather resistance, a hindered amine-based light stabilizer, a benzotriazole-based, benzophenone-based, or benzoate-based ultraviolet absorber, a metal salt of an acid phosphate, and a fine particle inorganic pigment are added to the surface layer. be able to.

As the hindered amine light stabilizer, those having a piperidine structure such as 2,2,6,6-tetramethylpiperidine or 1,2,2,6,6-pentamethylpiperidine as a partial structure are preferable. For example, dimethyl succinate / 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, bis (2,2,6,6-tetramethyl-4-piperidyl) ) Sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, (poly [{6- (1,1,3,3-tetramethylbutyl) amino-1,3,5- Triazine-2,4-diyl
｛(2,2,6,6-tetramethyl-4-piperidyl)
Imino {hexamethylene} (2,2,6,6-tetramethyl-4-piperidyl) imino}]).

As the ultraviolet absorber, 2- (5-methyl-2-methyl-2-benzotriazole) is used.
(Hydroxyphenyl) benzotriazole, 2- [2-
Hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2-
(3,5-di-t-butyl-2-hydroxyphenyl)
Benzotriazole, 2- (3-t-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-t-butyl-2-hydroxyphenyl) -5-chloro Benzotriazole, 2-
(3,5-di-t-amyl-2-hydroxyphenyl)
Benzotriazole, 2- (2'-hydroxy-5'-
t-octylphenyl) benzotriazole and the like, as benzophenone-based ultraviolet absorbers, 2,4-dihydroxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, -Hydroxy-4-methoxybenzophenone, pt-butylphenyl salicylate-2-hydroxy-4-methoxybenzophenone and the like, and 2,4-di-t-butylphenyl-3 ′, 5 as a benzoate-based ultraviolet absorber. '-Di-t-butyl-
4'-hydroxybenzoate, pt-butylphenyl-salicylate and the like can be mentioned.

The metal salts of acidic phosphoric acid esters used as ultraviolet absorbers include stearyl acid phosphate, magnesium stearyl phosphate, and the like.
Aluminum stearyl phosphate, calcium stearyl phosphate, zinc stearyl phosphate,
Barium stearyl phosphate and the like can be mentioned. Examples of the fine particle inorganic pigment include zinc oxide, tin oxide-based conductive fine powder, titanium oxide, TiO2.SnO2 (Sb-doped),
Barium sulfate-based conductive powder and the like can be mentioned. Two or more of these additives may be used in combination. It is preferable that the surface layer and thus the protective layer have an ultraviolet absorbing ability by adding an ultraviolet absorber because not only the light resistance of the protective layer but also the light resistance of the image can be improved. However, as described above, the light resistance cannot be sufficiently improved only by providing the protective layer with the ultraviolet absorbing ability. The amount of the UV absorber added is 0.01 to
It is preferably 20%, more preferably 0.1 to 10%. The light transmittance of the ultraviolet part by addition is 3 at 300 nm.
% Is preferable.

The adhesive layer mainly contains a resin having good adhesiveness when heated, such as an acrylic resin, a vinyl chloride resin, a polyester resin, a vinyl acetate resin, a vinyl chloride vinyl chloride resin, a polyamide resin, and a silicone resin. The same additives as those for the surface layer may be added as additives. The adhesive layer is formed on the surface layer by coating and drying a solution of a resin or an additive, preferably in a thickness of about 0.1 to 5 μm, in the same manner as the formation of the surface layer. . The image receiving sheet of the present invention is not particularly limited as long as it is an image receiving sheet used for ordinary thermal transfer. Preferably, the image receiving layer is provided with an image receiving layer on at least one surface of a substrate. The base material of the image receiving sheet is
Synthetic paper, cellulose paper, cast-coated paper, synthetic resin film, card made of synthetic resin, base material in which synthetic paper is bonded to both sides of cellulose paper, and the like are used. Since the higher the adhesion to the color material layer, the more uniform the transfer of the dye during recording is, the surface is preferably smooth, and if possible, a substrate having a Beck smoothness of 10,000 seconds or more should be used. preferable. From this point, synthetic paper and synthetic resin film,
A substrate using a card is preferred.

The image receiving layer is a layer mainly composed of a resin, and has a role of receiving a dye and forming an image. As the resin, a resin which easily dyes a dye is preferable. For example, a vinyl acetate resin, a polyvinyl chloride resin, a polyester resin, an AS resin, a polyvinyl acetal resin, and the like can be given. These can be used in combination. It is not preferable to use a resin having a glass transition point that is too low because an image blurs during storage. As the image receiving layer, an image receiving layer having a glass transition point of 35 ° C. or higher is preferable. Additives can be added to the image receiving layer, if necessary, in addition to the resin. Examples of the additive include, but are not limited to, a curing agent such as isocyanate for curing the resin, and a release agent such as silicone added for preventing fusion with the colorant layer during thermal transfer. . An anchor coat may be provided between the image receiving layer and the substrate to enhance the adhesiveness.

Using a transparent film as the base material of the image receiving sheet,
After the image is formed on the image receiving layer, the image receiving layer surface is pressed against another opaque substrate, and the image is viewed through the transparent film of the substrate, so that the transparent film itself serving as the protective layer serves as a protective layer. Usage is also possible, in which case it is preferable that the transparent film contains additives such as an ultraviolet absorber and an antioxidant. There is also a method in which an image receiving layer is formed on a base material of an image receiving sheet so as to be peelable, and the peelable image receiving layer is used as an intermediate recording layer. In this case, after an image is formed on the intermediate recording layer, the intermediate recording layer is pressed against the surface of another final recording material, the base material is peeled off, the intermediate recording layer is left on the final recording material, and the image is subjected to intermediate image reception. The intermediate recording layer itself functions as a protective layer in a configuration in which the layers are viewed through layers. In this case, the intermediate recording layer preferably contains additives such as an ultraviolet absorber and an antioxidant. In this method, a good lightfast image is formed on the intermediate recording layer using a bispyrazolone methine dye as the yellow dye and an indophenol cyan dye as the cyan dye, and this is used as the desired final recording material. Since the image can be transferred, a material on which an image is finally formed can be freely selected.

[0033]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist. In the following, “%” and “parts” are expressed in terms of weight unless otherwise specified. Example 1 (a) Preparation of Cyan Thermal Transfer Sheet Dye 1-1 (In the general formula (1), -A- is -COO
_{-, R 1, R 2,} R 3 is ethyl, R _4, R ₅ is a methyl group, X is a chlorine atom) 70 parts of a phenoxy resin (trade name:
PKHH, manufactured by Union Carbide Co., Ltd.) 100 parts,
125 parts of methyl ethyl ketone and 450 parts of toluene
Part and 300 parts of tetrahydrofuran (THF) were mixed and stirred, and a 6 μm polyester film was coated on a 6 μm polyester film using a bar coater to a dry thickness of 1 μm and dried. A layer was formed. On the back surface, 10 parts by weight of an acrylic resin (trade name: BR-100, manufactured by Mitsubishi Rayon Co., Ltd.), 1 part by weight of amino-modified silicone oil (trade name: KF393, manufactured by Shin-Etsu Chemical Co., Ltd.)
And a liquid obtained by mixing 89 parts by weight of toluene with a bar coater, and dried by coating so as to have a dry thickness of 1 μm to provide a heat-resistant layer.

(B) Preparation of yellow thermal transfer sheet 90 parts of dye 2-1 (in the general formula (2), R ₆ and R ₇ are phenyl groups and R ₈ and R ₉ are methyl groups), and phenoxy resin ( Product name: PKHH, manufactured by Union Carbide Co., Ltd.)
Similarly, an ink obtained by mixing and stirring 100 parts, 125 parts of methyl ethyl ketone, 450 parts of toluene, and 300 parts of tetrahydrofuran (THF) was mixed with 6 μm of ink.
The resulting polyester film was coated and dried using a bar coater to a dry film thickness of 1 μm to form a yellow color material layer. Similarly to (a), 10 parts by weight of an acrylic resin (trade name: BR-100, manufactured by Mitsubishi Rayon Co., Ltd.) and amino-modified silicone oil (trade name: KF39) on the back surface
3, Shin-Etsu Chemical Co., Ltd.) 1 part by weight and toluene 89
The liquid obtained by mixing parts by weight was applied and dried using a bar coater so that the dry thickness became 1 μm, and a heat-resistant layer was provided.

(C) Formation of protective layer Acrylic resin (BR-100, manufactured by Mitsubishi Rayon) 80
Part, ultraviolet ray absorbent (2- (3,5-di-t-butyl-
2-hydroxyphenyl) benzotriazole, trade name: TINUVIN320 manufactured by Nippon Ciba Geigy Co., Ltd.) 5 parts, 40 parts of methyl ethyl ketone, and 40 parts of toluene were stirred to obtain a coating liquid having a thickness of 6 with releasability.
was coated on a film having a thickness of μ to form a resin layer having a dry thickness of 2 μm. On top of this, a protective layer having a total thickness of 3 μm of a dry layer of a methyl ethyl ketone solution of an acrylic resin emulsion (trade name: Polysol AT2011, manufactured by Showa Polymer Co., Ltd.) was provided as an adhesive layer.

(D) Preparation of Image Receiving Sheet 70 parts of polyvinyl phenyl acetal resin, vinyl chloride / vinyl acetate / vinyl alcohol copolymer resin (trade name:
VAGD, manufactured by Union Carbide Co., Ltd.) 25 parts, denaturing silicone varnish (trade name: TSR-160, solid content concentration: 60%, manufactured by Toshiba Silicone Co., Ltd.) 15 parts, phthalic acid diester (trade name: K-3220, Kao Corporation 15 parts, hexamethylene diisocyanate polyfunctional isocyanate compound (trade name: Mytec NY-71)
0A, 75% solid content, 6 parts by Mitsubishi Chemical Corporation, 1 part of amino-modified silicone oil (KF393, Shin-Etsu Chemical Co., Ltd.), 1 part of methyl ethyl ketone 300
Parts and 300 parts of toluene were mixed and stirred, and the resulting solution was applied to a 150 μm-thick polypropylene synthetic paper (trade name: YUPO FPG150, manufactured by Oji Yuka Synthetic Paper Co., Ltd.) using a wire bar and dried (dried). An image receiving sheet was prepared by heat-treating the film in an oven at 80 ° C. for 12 hours. The above polyvinyl phenyl acetal resin was obtained by acetalizing polyvinyl alcohol (degree of saponification: 99 mol%, degree of polymerization: 1700) with phenylacetaldehyde, and had a structure represented by the following formula.

[0037]

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(E) Print Record The color material layer surface of the thermal transfer sheet prepared as in (a) above and the image receiving layer surface of the image receiving sheet prepared as in (b) above are overlapped. Using a partial grace type line thermal head having a heating resistor density of dots / mm, 16.6 (6) lines (dots) / mm in the feed direction.
Printing was performed at an applied power of 0.20 W / dot at a speed of ms / line. Printing was performed with the time applied to the head per line being 12 ms. By this method, a printed matter of cyan and yellow was obtained, and furthermore, a yellow printed matter and a cyan printed matter were overprinted to obtain a green printed matter. Further, the protective layer prepared in (c) is superimposed on the yellow, cyan and green recordings so that the recording surface and the adhesive layer are in contact with each other, and the opposite surface of the protective layer is coated with silicone oil to provide lubricity. After that, the surface having lubricity was heated by using the above-mentioned thermal head to adhere the image and the protective layer. Thereafter, the substrate was peeled off to obtain a record having a protective layer formed on the surface.

(F) Measurement of density and color The density of the dark color of the printed matter printed as in the above (d) is measured with a reflection densitometer (trade name: Macbeth RD-920, SPI
Built-in filter with spectral sensitivity characteristics, manufactured by Macbeth)
Was measured. As a result, the density was 2.0 for cyan and 1.6 for yellow.

(G) Lightfastness test A dark sample of the transferred product printed as in (d) above was tested with a lightfastness tester using a xenon lamp (trade name:
Using a xenon fade meter FAL-25AX, manufactured by Suga Test Instruments Co., Ltd.), an 80-hour light resistance test was performed.
The printed matter before the test and that after the test were compared with JIS Z-87.
Using a color difference meter (trade name: Spectral color difference meter SZ- # 80, manufactured by Nippon Denshoku Industries Co., Ltd.) having an optical system conforming to No. 22
The measurement was performed with a C light source and a viewing angle of 2 degrees. The CIELAB color difference was as small as 8.0 for cyan, 5.0 for yellow, and 11.0 for green.

Examples 2 to 7 In place of the dyes used in Example 1, the following Table
A test was conducted in the same manner as in Example 1 except that the dyes were used in the combinations shown in Table 1, and the results are shown in Table 2. In each case, the concentration was high and the light resistance was good.

[0042]

[Table 1]

In Table 1, dyes 1-2 to 1
-7, dyes 2-2 to 2-7 each have the following structure
It is. Dye 1-2: In formula (1), -A- is -CO
-, R₁ Is a pentyl group, R _Two , R_Three Is an ethyl group, and R4 is
A methyl group, R5 is a hydrogen atom, and X is a chlorine atom. Dye 1-3: In formula (1), -A- is -CO
-, R₁ Is a furan group, R_Two, R_Three Is an ethyl group, R4 is
A tyl group, R5 is a methyl group, and X is a chlorine atom. Dye 1-4: In formula (1), -A- is -COO
-, R₁ Is a benzyl group, R_Two , R_Three Is an ethyl group, R4,
R5 is a methyl group and X is a hydrogen atom. Dye 1-5: In formula (1), -A- is -CO
-, R₁ Is a methyl group, R_Two, R_Three Is an ethyl group, R4, R
5 is a methyl group and X is a hydrogen atom. Dye 1-6: In general formula (1), -A- is -CO
-, R₁ , R_Two , R_Three Is an ethyl group, R4 is a methyl group, R
5. X is a hydrogen atom. Dye 1-7: In formula (1), -A- is -CO
-, R₁ Is an ethoxyethyl group, R_Two , R_Three Is an ethyl group,
R4 is a methyl group, R5 and X are hydrogen atoms. Dye 2-2: In the general formula (2), R6 and R7 are o-
Toluyl group, R8 and R9 are methyl groups. Dye 2-3: In the general formula (2), R6 and R7 are
Nyl group, R8 is methyl group, R9 is ethoxycarbonyl group
It is. Dye 2-4: In the general formula (2), R6 and R7 are
Nyl group, R8 and R9 are butoxycarbonyl groups. Dye 2-5: In formula (2), R6 is phenyl
R7 is an o-toluyl group; R8 and R9 are methyl groups.
You. Dye 2-6: In the general formula (2), R6, R7, R
8, R9 is a methyl group. Dye 2-7: In the general formula (2), R6 and R7 are
The pill group, R8 and R9 are methyl groups.

Example 8 A test was conducted in the same manner as in Example 1 except that no ultraviolet absorber was added to the protective layer in (c) of Example 1. Its light fastness was inferior to that of Example 1, but sufficient results. The results are shown in Table-2.

Example 9 A recording having a protective layer on the surface was obtained by the following printing method using the following intermediate image receiving member instead of the image receiving sheet of Example 1. When it was tested in the same manner as in Example 1, light resistance was good. The results are shown in Table-2. (H) Intermediate Image Receptor 80 parts of an acrylic resin (BR-100, manufactured by Mitsubishi Rayon Co., Ltd.) and an ultraviolet ray absorbent (2- (3,5-di-t-butyl-2-hydroxy) Phenyl) benzotriazole, trade name: TINUVI
N320 (manufactured by Nippon Ciba Geigy Co., Ltd.), a coating liquid obtained by stirring 5 parts of methyl ethyl ketone 40 parts and toluene 40 parts was applied to form a surface layer having a dry thickness of 2 μm. On top of that, the image-receiving layer described in “(d) Preparation of image-receiving body” in Example 1 had a dry thickness of 7 in total including the surface layer.
μm, dried, and heat-treated in an oven at 80 ° C. for 12 hours to produce an intermediate image receiving body having an intermediate image receiving layer provided on a substrate.

(I) Printing and Recording The color material layer surface of the heat-sensitive transfer sheet produced in the same manner as in Example 1 and the intermediate image-receiving layer of the intermediate image-receiving body produced as in (h) above were superposed. Under the same printing conditions as in Example 1, cyan and yellow prints were obtained, and yellow was printed on top of cyan to obtain green prints. This image was superimposed on a 150-μm-thick white PET film which had been subjected to an easy adhesion treatment, passed through a laminator, and the image surface was adhered to the white PET film. By peeling off the release PET film that was the base material of the intermediate image receiving body,
An image having a protective layer on the inverted surface of the image was obtained.

Comparative Example 1 Instead of the dye 2-1 used in Example 1 (b),
A test was conducted in the same manner as in Example 1 except that a quinophthalone-based yellow dye represented by the following structural formula was used. At this time, it was found that the solubility of the pigment in the colorant layer coating solution was insufficient, so a solvent was added and the colorant layer was formed with a transparent coating solution, but the colorant layer was opaque. , Precipitation of the dye was observed. The yellow density of the transfer was insufficient. Table-
2 is shown.

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Comparative Example 2 In place of the dye 2-1 used in Example 1 (b),
A test was conducted in the same manner as in Example 1 except that a pyridoneazo-based yellow dye represented by the following structural formula was used. As a result, the yellow density was as high as 2.3. The light fastness of green color mixture was 20.0, which was an unsatisfactory result. This is considered to be the result of the deterioration of light resistance in green due to the catalytic fade phenomenon. The results are shown in Table-2.

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Comparative Example 3 The procedure of Example 1 was repeated, except that 60 parts of a styryl dye represented by the following structural formula was used instead of the dye 2-1 used in (b) of Example 1. Test. Although a high transfer density was obtained for the yellow color, the light resistance of the green color was insufficient, which is considered to be the effect of the catalytic fade phenomenon. The results are shown in Table-2.

[0052]

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Comparative Example 4 A test was conducted in the same manner as in Example 1 except that the dye 1-1 used in (a) of Example 1 was replaced by an anthraquinone cyan dye represented by the following structural formula. Was. The concentration is
A result as low as 1.5 was obtained. Its lightfastness was an unsatisfactory result. Table 2 shows the results.

[0054]

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[0055]

[Table 2]

[0056]

[Table 3]

[0057]

According to the present invention, it is possible to supply a heat-sensitive transfer recording which is excellent in light resistance and high in density.

Claims (13)

[Claims] 1. A thermal transfer sheet used in a sublimation thermal transfer recording method, wherein a protective layer is provided on the surface of a transfer image,
At least a plurality of color material layers are provided on one surface of the substrate in a face-sequential manner, the at least one color material layer contains an indophenol-based cyan dye, and the other at least one color material layer A heat-sensitive transfer sheet containing a bispyrazolone methine yellow dye. 2. The heat-sensitive transfer sheet according to claim 1, wherein the indophenol cyan dye is a dye represented by the following general formula (1). Embedded image (Wherein -A- represents -CO- or -COO-;
₁ is a lower alkyl group which may be substituted, a lower alkenyl group which may be substituted, an aryl group which may be substituted, an aralkyl group which may be substituted, or
An alkyl group or a heterocyclic ring which may be substituted with a halogen atom, R ₂ and R ₃ independently represent a lower alkyl group which may be substituted, R ₄ represents a methyl group or an ethyl group, ₅ represents a hydrogen atom or a methyl group, and X represents a hydrogen atom or a halogen atom. ) 3. The heat-sensitive transfer sheet according to claim 1, wherein the bispyrazolone methine yellow dye is a dye represented by the following general formula (2). Embedded image (Wherein R ₆ and R ₇ independently represent a lower alkyl group which may be substituted, a lower alkenyl group which may be substituted, or an aryl group which may be substituted, and R ₈ and R ₉ Is independently an optionally substituted lower alkyl group, dialkylamino group, -COOY group, -CONZW
Y represents a lower alkyl group which may be substituted,
Represents an optionally substituted lower alkenyl group or an optionally substituted aryl group, and Z and W each independently represent a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted lower alkenyl And an aryl group which may be substituted. ) 4. In the general formula (1), -A- is-
Represents CO- or -COO-, R ₁ is a lower alkyl group, a lower alkenyl group, an aralkyl group having 7 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, chloroethyl group, a lower alkoxy-lower alkyl group, tetrahydrofurfuryl Group, aralkyloxyethyl group having 9 to 12 carbon atoms, aryloxyethyl group having 8 to 12 carbon atoms, lower alkenyloxyethyl group, tetrahydrofurfuryloxyethyl group, or containing O, N or S as a hetero atom R ₂ and R ₃ represent a methyl group or an ethyl group; R ₄ represents a methyl group or an ethyl group;
3. The thermal transfer sheet according to claim 2, wherein ₅ represents a hydrogen atom or a methyl group, and X represents a hydrogen atom or a chlorine atom. 5. In the general formula (1), -A- is-
Represents CO- or -COO-, R ₁ represents a lower alkyl group, a lower alkenyl group, a phenyl group, a toluyl group, a benzyl group, a tetrahydrofurfuryl group, a lower alkoxy lower alkyl group, a furan, a pyridine, a thiophene,
R ₂ and R ₃ each represent an ethyl group, R ₄ represents a methyl group or an ethyl group, R ₅ represents a hydrogen atom or a methyl group, and X is a hydrogen atom or a chlorine atom. The heat-sensitive transfer sheet according to claim 2. 6. In the general formula (2), R ₆ and R ₇
Is a lower alkyl group, an optionally substituted aryl group,
Represents an aralkyl group, R ₈ and R ₉ are a lower alkyl group,-
4. The heat-sensitive transfer sheet according to claim 3, wherein a COOY group is represented, and Y is a lower alkyl group, an optionally substituted aryl group, or an aralkyl group. 7. In the general formula (2), R ₆ and R ₇
Represents a lower alkyl group, a phenyl group which may be substituted with a methyl group or a halogen atom, a benzyl group,
R ₈ and R ₉ represent a lower alkyl group or a —COOY group;
4. The heat-sensitive transfer sheet according to claim 3, wherein is a phenyl group or a benzyl group which may be substituted with a lower alkyl group, a methyl group or a halogen atom. 8. The method according to claim 1, wherein the indophenol-based cyan dye is
In the general formula (1), -A- represents -CO- or -COO-.
Then R₁ Is methyl, ethyl, propyl, butyl
Group, pentyl group, benzyl group, lower alkoxyethyl
Represents a furan ring, R_Two And R_Three Represents an ethyl group,
R_FourRepresents a methyl group or an ethyl group; _FiveIs a hydrogen atom
Or a methyl group, and X represents a hydrogen atom or a chlorine atom
This is a dye that represents a bispyrazolone methine yellow dye
In the general formula (2), R₆, R₇Is a methyl group, an ethyl group,
Represents propyl, butyl, phenyl, and toluyl groups
Then R ₈, R₉Represents a methyl group, an ethoxycarbonyl group,
Characterized as a dye that represents a toxic carbonyl group
The heat-sensitive transfer sheet according to claim 1. 9. The thermal transfer sheet according to claim 1, wherein a protective layer capable of thermal transfer is provided on one surface of the substrate together with a plurality of color material layers in a sequential manner. 10. The heat-sensitive transfer sheet according to claim 9, wherein the protective layer has a function of blocking ultraviolet rays. 11. A thermal transfer sheet for thermal transfer recording, in which a color material layer is provided on at least one surface of a substrate, and after an image is obtained on an image receiving sheet, a protective layer is provided on the surface of the image. A sublimation thermal transfer recording method, wherein a bispyrazolone methine dye is used as a yellow dye, and an indophenol cyan dye is used as a cyan dye. 12. An image is formed on an intermediate recording layer by using a thermal transfer sheet for thermal transfer recording in which a coloring material layer is provided on at least one surface of a base material, and thereafter, the intermediate recording layer is finally formed. In a sublimation thermal transfer recording method for obtaining a recorded image having a protective layer formed thereon by thermal transfer to the surface of a recording material, a bispyrazolonemethine dye is used as a yellow dye, and an indophenol cyan dye is used as a cyan dye. A thermal transfer recording method, characterized in that: 13. A dye according to claim 11, wherein the indophenol cyan dye and the bispyrazolone methine yellow dye are the dyes according to claim 8, respectively.
2. The thermal transfer recording method according to item 2.