JPH0692040A - Sheet for sublimation type color thermal transfer - Google Patents

Abstract

PURPOSE:To provide an extremely efficient transfer system reducing the corresponding energy of a thermal head at the time of transfer and enabling high speed transfer by ensuring high density using highly light-resistant dye group and to obtain a transfer article having high resolving power and high image quality, extremely excellent in light resistance capacity as compared with a silver salt photograph and also excellent in preservability. CONSTITUTION:In using a highly light-resistant dye group, this dye group is prepared by mixing two or more kinds of dyes with a single solvent or a mixture of two or more kinds of solvents. Concretely, in (n) dyes constituted of A, B, C...N, when the total amt. of dyes (ag+bg+cg...ng) within a solubility reducing degree range generated by the coexistence of (n-1) dyes and a used chemical agent is set within the solubility of a specific solvent used in the dissolution of dyes, dyes can be easily dissolved in a specific solvent system used in dissolution in high concn. By this system, predetermined ink coating density is ensured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sublimation type color thermal transfer sheet used in a thermal transfer recording apparatus, and in particular, a sublimation type colorant which can secure a sufficient dye density when a strong lightfast dye is adopted. The present invention relates to a thermal transfer sheet.

[0002]

2. Description of the Related Art A thermal transfer recording apparatus is provided with a heating element such as a thermal head for applying heat to a thermal transfer sheet, and a gradation image is transferred to a receptor by changing the amount of heat of the heating element. .

Conventionally, as a color thermal transfer sheet used for this kind of use, one prepared by selecting dyes of specific three primary colors from sublimable dyes is known.

Originally, these three primary color dyes selected were mainly selected from the group of high concentration type azo chromophores having a large molecular extinction coefficient and excellent sensitivity. However, in the azo chromophore group, the unsaturated double bond portion in -N = N- is liable to be sensitively cleaved and decomposed by singlet oxygen or a reducing gas due to the irradiation of ultraviolet rays. It was easy to cause discoloration and fading by degrading the original functionality of the above, and therefore it was unsatisfactory in terms of light resistance.

Therefore, the inventor of the present application also uses the JIS L 0841 (fastness to sunlight), JIS L 0842 (fastness to carbon arc lamp), and JIS L 0843 (fastness to xenon arc lamp) test methods. For the purpose of obtaining a transfer material which can secure a grade to 8 grade and can exhibit light resistance performance higher than that of silver salt photography, at least three types of ink layers of cyan, magenta, and yellow, or their hues are provided on one surface of the substrate. In the sublimation type color thermal transfer sheet in which four types of ink layers in which black is added are sequentially applied, the basic molecular skeleton of the sublimable dye that constitutes the cyan ink layer is an anthraquinone-based magenta ink layer. The basic molecular skeleton of the sublimable dye constituting the above is the anthraquinone type, and the basic molecular skeleton of the sublimable dye constituting the yellow ink layer is the anthraquinone type and the quinophthalone type. Akurido system, nitro-based,
It is being studied to prepare pyridone type, pyrazolone type, and the above black by mixing the above three primary colors or mixing these three primary colors with orange, violet, green and the like. That is, it is considered to use a strong light fastness dye as the sublimation dye that constitutes each of the cyan, magenta, yellow, and black ink layers.

[0006]

Originally, when a dye is applied in a highly dispersed state in which the dye is unstable and its solubility is higher than the solubility in a solvent, the ink-coated surface becomes dull due to dye molecule association, and the transferred product is extremely unsolved. It is a well-known fact that an unclear image having poor image quality is formed. Therefore, in order to form a stable high-concentration ink coated surface, it is possible to obtain a predetermined ink concentration by combining and dissolving at least two kinds of dyes within the solubility range of the dye in the solvent. However, these strong lightfast dyes generally have low solubility in various solvents, and at the same time have low molecular absorbance at the absorption maximum wavelength (λmax) due to the molecular structure, the ink coating concentration of only a single dye is extremely low. Therefore, the transfer effect does not reach a practical standard level.

In the present invention, when the strong lightfast dye is used, a group of these dyes is mixed in an amount within a certain solvent solubility of at least two kinds and prepared to prepare a predetermined high density ink coated surface. It is possible to obtain a high density and high resolution image quality of the transferred material.
Further, it is possible to obtain a highly robust transfer product which has good storage stability and can exhibit strong light resistance more than that of silver salt photography. It is an object of the present invention to provide a sublimation type color thermal transfer sheet having such excellent properties.

[0008]

According to the present invention, at least three types of ink layers of at least cyan, magenta and yellow, or four types of ink layers obtained by adding black to these hues are sequentially coated on one surface of a substrate. In the manufactured sublimation type color thermal transfer sheet, the sublimation dye constituting each of the cyan, magenta, yellow and black ink layers is a strong light fastness dye, and these strong light fastness dyes are mixed with a single solvent or 2 Each ink is prepared by mixing two or more kinds in a mixed solvent of one or more kinds.

There are many difficulties in forming an ink using a strong lightfast dye. That is, these strong light-fast dyes, especially anthraquinone skeletons have significantly lower solubility in various solvents than azo skeletons, and at the same time, have a small molecular absorption at the maximum absorption wavelength (λmax) due to the molecular structure,
Moreover, since the transfer efficiency is low, the transfer density is likely to be extremely low. Therefore, it is extremely difficult to obtain a practical coating density (OD value of 2.0 or higher with a Macbeth RD-914 densitometer) unless the total amount of at least two dyes is used. Therefore, in order to increase the concentration, it is necessary to dissolve a large amount of coloring material in a solvent, but in many cases, especially in a toluene / MEK mixed solvent system as a general-purpose solvent system, the solubility is extremely small, and therefore two or more kinds are used. By configuring the ink with the total amount of the dye, it is possible to obtain a predetermined high density.

In the present invention, a strong lightfast dye is mixed with two or more dyes in a single solvent or in a mixed solvent of two or more solvents to prepare an ink, thereby increasing the total concentration of the dyes to obtain a desired concentration. It is what you get. It is desirable to dissolve two or more kinds of dyes in a suitable solvent corresponding to each of them, and to superpose them to obtain a predetermined high concentration.
A predetermined high concentration is ensured by mixing and mixing each of the dyes composed of one or more species with an amount within the solubility range.
From the ink-coated surface prepared in this way, it is possible to obtain high-density, high-resolution, highly robust image quality with excellent lightfastness and heat-preservability, and at the same time, reduce the energy required for the thermal head during transfer. High-speed transfer is also possible and an extremely efficient transfer system can be provided.

In an anthraquinone chromophore pigment skeleton, which is an example of a strong light fastness dye, the electron density in the molecule is extremely stable, so that it can be easily converted to singlet oxygen or reducing gas due to ultraviolet irradiation. Is less likely to be decomposed, and is therefore more lightfast than other chromophore groups. However, the molecular extinction coefficient due to the target molecular skeleton is small, and because it is poorly soluble in general-purpose solvents, it is not possible to obtain a predetermined concentration by itself, and it is required to set at least two or more combination prescriptions. It Therefore, it is preferable to select the dyes of the three primary colors from among the anthraquinone-based chromophores.

Here, in terms of the color wavelength of the anthraquinone chromophore, the chromophore is orange to
Red-violet-blue occupy the main point. Therefore, the yellow component is formed based on the quinophthalone chromophore. This quinophthalone chromophore is difficult to aggregate with unstable double bonds and other dye molecules,
That is, it has a stable molecular structure that facilitates hydrogen bonding inside the molecule. Therefore, as for the yellow component, based on the quinophthalone-based chromophore dye, the above-mentioned anthraquinone-based chromophore dye and further acryl-based, nitro-, pyridone-based, and pyrazolone-based chromophore dyes are appropriately added. Therefore, it is preferable to configure it.

Further, as for black, cyan, magenta centering on anthraquinone chromophore, and yellow containing anthraquinone chromophore based on quinophthalone chromophore are mixed, or orange, violet, and green are added to these. By mixing such a composition, the three primary colors and all of the black can be composed of the dye having the anthraquinone chromophore as the center.

At the carbon positions 1 to 8 in the anthraquinone chromophore pigment skeleton used in the present invention,

[Chemical 1] At least at positions 1, 4, 5 and 8 are —NH ₂ group or —NHR group (R is a lower alkyl group which may be linear or branched, cycloalkyl group, alkenyl group, aryl group, aralkyl group, alkoxyalkyl group) ) Or -OH group is coordinated with at least one of -NH ₂
Group, or any of the three groups of the -NHR group or the -OH group, is coordinated with two or more groups, and in the coordination of 2,3,6,7, at least the following: No linking group or 1 at any of 2, 3, 6, 7 positions
Or more, or two or more of the following bonding groups are coordinated.

Anthraquinone chromophore dye skeleton Bonding group at carbon positions 2, 3, 6, 7 (same content as X: R) --O--R--S--R

[Chemical 2]

[Chemical 3] -CSO-R (or -COS-R) -COOR

[Chemical 4]

[Chemical 5]

[Chemical 6]

[Chemical 7] -CN and halogen atom groups Anthraquinone-based chromophore groups satisfying the respective conditions in the above contents are used.
CI Solvent Red 5 is an anthraquinone pigment group (red to blue, violet to green) that can be mentioned as solvent No. and CI disperse No.
2, CI Solvent Red 60, CI Solvent Red 111
, CI Solvent Red 138, CI Solvent Red 1
43, CI Solvent Red 146, CI Solvent Red 149, CI Solvent Red 150, CI Solvent Red 151, CI Solvent Red 152, CI Solvent Red 155, CI Solvent Red 168, CI Solvent Red 169, CI Solvent Red 177, CI Solvent Red 177 207, CI Solvent Red 230, CI Disperse Thread 1, CI Disperse Thread 4, CI Disperse Thread 11, CI Disperse Thread 15, CI
Disperse Red 22, CI Disperse Red 52, C.
I. Disperse Red 53, CI Disperse Red 55,
CI Disperse Red 60, CI Disperse Red 8
6, CI Disperse Thread 91, CI Disperse Thread 92, CI Disperse Thread 127, CI Disperse Thread 132, CI Disperse Thread 146, CI Disperse Thread 159, CI Disperse Thread 189, CI
Disperse Red 191, CI Disperse Red 207
, CI Disperse Thread 229, CI Disperse Thread 239, CI Disperse Thread 283, CI Disperse Thread 302, CI Disperse Thread 362, CI Disperse Thread 364, CI Solvent Blue 12, CI
Solvent Blue 21, CI Solvent Blue 35, CI Solvent Blue 36, CI Solvent Blue 45, CI Solvent Blue 59, CI Solvent Blue 63, CI Solvent Blue 78, CI Solvent Blue 83, CI Solvent Blue 94, CI Solvent Blue 95, CI Solvent Blue 97, CI Solvent Blue 105, CI Solvent Blue 112, CI Solvent Blue 122, CI Disperse Blue 1, CI Disperse Blue 3, CI Disperse Blue 5, CI Disperse Blue 6, CI Disperse Blue 7, CI Disperse Blue 14, CI Disperse Blue 19, CI Disperse Blue 22, CI
Disperse Blue 23, CI Disperse Blue 24, C.
I. Disperse Blue 26, CI Disperse Blue 27,
CI Disperse Blue 34, CI Disperse Blue 3
5, CI Disperse Blue 55, CI Disperse Blue 56, CI Disperse Blue 60, CI Disperse Blue 72, CI Disperse Blue 73, CI Disperse Blue 73: 1, CI Disperse Blue 77, CI Disperse Blue 81, CI Disperse Blue 87, CI Disperse Blue 87: 1, CI Disperse Blue 91, CI Disperse Blue 99, CI Disperse Blue 149, C.
I. Disperse Blue 154, CI Disperse Blue 15
8, CI Disperse Blue 165, CI Disperse Blue 185, CI Disperse Blue 197, CI Disperse Blue 198, CI Disperse Blue 214, CI Disperse Blue 288, CI Disperse Blue 331,
CI Disperse Blue 361, CI Disperse Blue
366, CI Solvent Violet 11, CI Solvent Violet 13, CI Solvent Violet 14, CI
Solvent Violet 31, CI Solvent Violet 32, CI Solvent Violet 33, CI Solvent Violet 34, CI Solvent Violet 36, CI
Solvent Violet 45, CI Disperse Violet 1, CI Disperse Violet 4, CI Disperse Violet 6, CI Disperse Violet
8, CI Disperse Violet 17, CI Disperse Violet 26, CI Disperse Violet 27,
CI Disperse Violet 28, CI Disperse Violet 31, CI Disperse Violet 35, CI
Disperse Violet 38, CI Disperse Violet 46, CI Disperse Violet 56, CI Solvent Green 3, CI Solvent Green 26, CI Solvent Green 28, CI Disperse Green 6: 1 etc.

CI Solvent Yellow 16 is an anthraquinone dye group that is preferably used as a yellow component.
3, CI Bat Yellow 3, CI Disperse Orange
11, CI Disperse Orange 119, CI Solvent Orange 60, CI Solvent Orange 64, CI Solvent Orange 68, CI Solvent Orange 71, CI Solvent Orange 86, etc. It should be noted that there is a small number of anthraquinone-based dye groups as a yellow component, and it is necessary to use an alternative chromophore basic skeleton group that has strong light resistance and stable intramolecular electron density. As a group, CI solvent yellow 33, CI solvent yellow 114, CI solvent yellow 128, C.
I. Solvent Yellow 129, CI Solvent Yellow 15
7, CI Disperse Yellow 49, CI Disperse Yellow 54, CI Disperse Yellow 64, CI Disperse Yellow 149, CI Disperse Yellow 160, C.
I. Disperse Yellow 224, etc., CI Disperse Yellow 122, etc. as an acrid dye group, CI Disperse Yellow 1, CI Disperse Yellow 9, CI Disperse Yellow 33, CI Disperse Yellow 42, as a nitro dye group CI as a pyridone dye group
Disperse Yellow 231 and the like, and CI Solvent Yellow 93 and the like as a pyrazolone dye group.

By forming the sublimation type color thermal transfer sheet selected from each of the cyan, magenta and yellow color material groups as described above, the transferred material is a silver salt photograph due to the high light resistance peculiar to the anthraquinone chromophore. The above strong light fastness can be obtained. Especially in the present invention, when using a strong light fastness dye represented by an anthraquinone dye, two or more kinds of these strong light fastness dyes are mixed in a single solvent or a mixed solvent of two or more kinds. To prepare each ink. Specifically, in the n color material groups composed of A, B, C, ..., N, within the specific solvent solubility to be the melting point, and (n-1) If a total amount of dyes (ag + bg + cg + ... + ng) within the degree of dissolution decrease caused by coexistence is set and mixed, it can be easily dissolved at a high concentration in a specific solvent system to be dissolved, so that a predetermined ink coating concentration can be secured.

The ink used for forming the ink layer of the present invention is prepared by dissolving a sublimable dye in a solvent together with a binder, and 3 to 5 parts by weight of the dye is added to 100 parts by weight of the total ink. As described above (at least within the solubility range in the total amount of n strong lightfast dyes to be constituted), it is preferable that 1 to 20 parts by weight of the binder and 96 to 70 parts by weight of the solvent be present.

As the solvent, chlorine-based hydrocarbons such as methylene dichloride, chloroform, chlorobenzene, etc., toluene, xylene, etc. are used in order to dissolve the above-mentioned dye in a high concentration and form a deep and high-resolution image. The aromatic hydrocarbons described above or ketones such as methyl ethyl ketone and cyclohexanone are used.

As the binder, the color thermal transfer sheet and the thermally transferred image can be stably stored, the light fastness of the ink layer and the image is not deteriorated, the compatibility with the dye is excellent, and the binder is compatible with the above solvent. From the viewpoint of having transparency, after the solvent evaporates and solidifies by melting, does not fuse to the receptor during thermal transfer, does not cause a phase in the color thermal transfer sheet and image, and has good adhesiveness to the sheet. A polyvinyl acetal resin having a glass transition temperature of 85 to 120 ° C., a saturated polyester resin, a mixture of a saturated polyester resin and a polycarbonate resin, or a polysulfone resin is used.

The above polyvinyl acetal resin is
It is preferable to use one having an appropriate viscosity and excellent coatability. On the other hand, since the polyvinyl acetal resin does not hold the dye chemically, an anchor coat such as polyester resin, polyurethane resin or polyamide resin is previously applied to the coated surface so that the dye does not seep out from the transfer layer when stored at high temperature. It is preferable to apply it to the base material.
The saturated polyester resin includes a resin formed by polycondensation of a dicarboxylic acid component and a diol component.

On the surface of the base material which does not face the thermal head, the above-mentioned inks of yellow, magenta, and cyan, or in addition to these inks, the color of black is sequentially applied and dried to form an ink layer. As the substrate applicable to the present invention, a plastic film such as polyester, polyimide, polysulfone, polystyrene, or polycarbonate can be used. If you apply a silicone resin, a fluorine-based resin, a fluorine-based lubricant or a surface-active agent to the surface of this film facing the thermal head in advance and provide a heat-resistant layer or a slipping layer, sticking (fusion) will occur. It can be prevented and is preferable.

The receptor for forming a high quality image by the sublimation type color heat transfer sheet of the present invention may be any one as long as the image recording surface is receptive to the dyes described above, such as high quality paper, synthetic paper and cloth. , Films, sheets and the like.
The surface of the receptor is coated with a solution containing an adhesive resin, a curing agent for this resin or a crosslinking agent for this resin, a solvent, a silicon-based fine white powder, and a surfactant having an affinity for this fine powder. It is preferable to provide a receiving layer.

[0024]

As described above, according to the present invention, the sublimation dye constituting each of the cyan, magenta, yellow and black ink layers is a strong light fastness dye, and these strong light fastness dyes are used alone. By preparing each ink by mixing two or more kinds in the solvent or the mixed solvent of two or more kinds, it is possible to secure a sufficient dye concentration when using the strong light fastness dye. And by ensuring a high density composed of these strong lightfast dye groups, the energy required for the thermal head at the time of transfer is low, and it becomes an extremely efficient transfer method capable of high-speed transfer. It is possible to obtain a transfer product having high resolution and high image quality and, at the same time, excellent in light fastness and excellent in storage performance as compared with silver halide photography and having high fastness.

[0025]

EXAMPLES Examples of the present invention will be described below. “Parts” used below means “parts by weight”.

<Example 1> A polyester resin was thinly applied to one side of a polyester film to form an anchor coat.

Next, four kinds of inks were prepared by the following composition for each color of yellow, magenta, cyan and black. These inks were applied in the order of yellow, magenta, cyan, and black to the surface of the above anchor coat over the entire width of the film to obtain a color thermal transfer sheet.

As the yellow ink dye, anthraquinone type CI solvent yellow 163, CI disperse orange 119 etc. are used, and a quinophthalone type CI disperse yellow 160, CI disperse yellow 224 etc. are used. Then, the total amount was set to about 40 parts. Polyvinyl acetal was used as the binder, and the total amount was 25 to 35 parts. Polyisocyanate was used as the crosslinking agent, and the total amount was 8 to 14 parts. Further, as the surface functional lubricant, a fluorocarbon-based surfactant is used, and the total amount is 2 to
It was 6 parts. And toluene / MEK 9 as solvent
A yellow ink was prepared by adding 05 to 925 parts.

Magenta ink As the dye, CI Solvent Red 168, CI Disperse Red 22, CI Disperse Red 53, CI Solvent Violet 36, etc. were used, and the total amount was about 50 parts. Polyvinyl acetal was used as the binder, and the total amount was 26 to 35 parts. Polyisocyanate was used as the crosslinking agent, and the total amount was 7 to 12 parts. A fluorocarbon-based surfactant was used as the surface functional lubricant, and the total amount was 2 to 8 parts. Then, 895 to 915 parts of toluene / MEK was added as a solvent to prepare a magenta ink.

Cyan ink CI Disperse Blue 60, CI Disperse Blue 87, CI Disperse Blue 198, CI Disperse Blue 7, CI Solvent Green 3, etc. were used as the dye, and the total amount was about 50 parts. . Polyvinyl acetal was used as the binder, and the total amount was 26 to 35 parts. Polyisocyanate was used as the crosslinking agent, and the total amount was 7 to 12 parts. Further, as the surface functional lubricant, a fluorocarbon-based surfactant is used, and the total amount is 2 to
8 parts. Then, dichloromethane is used as a solvent.
A cyan ink was prepared by adding 5 to 915 parts.

As the black ink dye, CI Disperse Yellow 231 or the like is used as a pyridone type, and CI Solvent Red 168, CI Disperse Violet 31, CI Solvent Blue 35, CI Solvent Blue 36 or the like is used. ,
The total amount was about 120 parts. Polyvinyl acetal was used as the binder, and the total amount was 25 to 35 parts. Polyisocyanate is used as the cross-linking agent, and the total amount is 8
-14 parts. A fluorocarbon-based surfactant was used as the surface functional lubricant, and the total amount was 2 to 6 parts. And dichloromethane as a solvent is 825-84.
5 parts were added to prepare a black ink.

<Embodiment 2> As in Embodiment 1, yellow,
4 for each color of magenta, cyan, and black
A seed ink was prepared. These inks were applied in the order of yellow, magenta, cyan and black on one side of a polyester film over the entire width of the film to obtain a color thermal transfer sheet.

Yellow ink: Anthraquinone type CI Solvent Yellow 163 and the like, nitro type dyes such as CI Disperse Yellow 42, and quinophthalone type C.
I. Disperse Yellow 54, CI Disperse Yellow
CI Disperse Yellow 122, etc. was used as the acrylate type, such as 149 etc., to make about 50 parts of the total amount. Polyvinyl acetal is used as the binder, and the total amount of 2
It was 6 to 35 parts. Polyisocyanate was used as the crosslinking agent, and the total amount was 7 to 12 parts. A fluorocarbon-based surfactant was used as the surface functional lubricant, and the total amount was 2 to 8 parts. Then, 895 to 915 parts of toluene / MEK was added as a solvent to prepare a yellow ink.

As magenta ink dyes, CI Disperse Red 146, CI Disperse Red 91, CI Disperse Red 132, CI
Disperse Red 207, CI Solvent Red 155,
CI Solvent Violet 31, CI Disperse Violet 31, etc. were used to make the total amount approximately 75 parts. Polyvinyl acetal is used as the binder, and the total amount of 2
It was set to 5 to 35 parts. Polyisocyanate was used as the crosslinking agent, and the total amount was 8 to 14 parts. A fluorocarbon-based surfactant was used as the surface functional lubricant, and the total amount was 2 to 6 parts. Then, 870 to 890 parts of toluene / MEK was added as a solvent to prepare a magenta ink.

Black ink CI Disperse Yellow 163 or the like is used as an anthraquinone type dye, CI Solvent Red 60, CI Disperse Violet 26, CI
Solvent Blue 63, CI Solvent Blue 331, etc. were used to make the total amount approximately 120 parts. Polyvinyl acetal was used as the binder, and the total amount was 25 to 35 parts. Polyisocyanate was used as the crosslinking agent, and the total amount was 8 to 14 parts. Further, as the surface functional lubricant, a fluorocarbon-based surfactant is used, and the total amount is 2 to
It was 6 parts. Then, dichloromethane is used as a solvent.
5 to 845 parts were added to prepare a black ink.

<Embodiment 3> Similar to Embodiments 1 and 2, in order to obtain the required high density for the purpose of OHP use for each color of yellow, magenta and cyan, the following four compositions including black were used. A high density ink was prepared. These required high-concentration inks were applied in order of yellow, magenta, cyan, and black on one side of a polycarbonate film over the entire width of the film to obtain a color thermal transfer sheet.

Yellow ink As an anthraquinone type dye, CI Solvent Yellow 163, etc., and a quinophthalone type C.
I. Disperse Yellow 49, CI Disperse Yellow
54, CI Disperse Yellow 64, CI Disperse Yellow 224, etc., Pyridone type CI Disperse Yellow 231 etc., Nitro type CI Disperse Yellow 42 etc., Acrid type CI Disperse Yellow 122 etc. Was used to make about 90 parts of the total amount. Polyvinyl acetal was used as the binder, and the total amount was 25 to 35 parts. Polyisocyanate was used as the crosslinking agent, and the total amount was 8 to 14 parts. A fluorocarbon-based surfactant was used as the surface functional lubricant, and the total amount was 2 to 6 parts. And, as a solvent, toluene / dichloromethane / MEK is 855-87.
A yellow ink was prepared by adding 5 parts.

As magenta ink dyes, CI Disperse Thread 11, CI Disperse Thread 53, CI Disperse Thread 60, CI Disperse Thread 91, CI Disperse Thread 127, CI
Disperse Red 168, CI Solvent Red 52, C.
I. Solvent Red 155, CI Disperse Violet 26, CI Disperse Violet 31, CI Solvent Violet 36, etc. were used, and the total amount was about 120 parts. As the binder, polyvinyl acetal is used,
The total amount was 25 to 35 parts. Polyisocyanate was used as the crosslinking agent, and the total amount was 8 to 14 parts. Also,
A fluorocarbon-based surfactant was used as the surface functional lubricant, and the total amount was 2 to 6 parts. Then, 825 to 845 parts of dichloromethane / chloroform as a solvent was added to prepare a magenta ink.

Cyan ink As the dye, CI Disperse Blue 7, CI Disperse Blue 56, CI Disperse Blue 60, CI Disperse Blue 87, CI Disperse Blue 149, CI
Disperse Blue 165, CI Disperse Blue 185
, CI Disperse Blue 197, CI Disperse Blue 198, CI Solvent Blue 105, CI Solvent Green 3, etc. were used, and the total amount was about 130 parts. Polyvinyl acetal was used as the binder, and the total amount was 25 to 35 parts. Polyisocyanate was used as the crosslinking agent, and the total amount was 8 to 14 parts. A fluorocarbon-based surfactant was used as the surface functional lubricant, and the total amount was 2 to 6 parts. Then, 815 to 835 parts of dichloromethane / chloroform as a solvent was added to prepare a cyan ink.

As the black ink dye, CI Solvent Yellow 163 etc. as anthraquinone type and CI Disperse Yellow 231 etc. as pyridone type are used, and CI Disperse Red 60, CI Disperse Red 168, CI
Disperse Violet 26, CI Solvent Blue 6
3, CI Solvent Blue 35, CI Solvent Blue 36
Etc. were used to make the total amount approximately 175 parts. As the binder, polyvinyl acetal is used, and the total amount is 25 to 35.
Part and Polyisocyanate was used as the crosslinking agent, and the total amount was 8 to 14 parts. A fluorocarbon-based surfactant was used as the surface functional lubricant, and the total amount was 2 to 6 parts. Then, 770 to 790 parts of dichloromethane was added as a solvent to prepare a black ink.

Next, polypropylene-based synthetic paper was used as a receiver. The following receiving layer coating liquid was applied to one surface of this synthetic paper to form a receiving layer. This coating liquid was prepared by dissolving polyester resin, polyisocyanate as a cross-linking agent, silicone-based surfactant, silicone-based white resin fine powder, and ultraviolet absorber in a solvent mixed with toluene and methyl ethyl ketone. .

The color thermal transfer sheets obtained in Examples 1, 2 and 3 were placed on the above synthetic paper, loaded into a video printer, and the still image on the TV screen was thermally transferred onto the synthetic paper. I got a natural color photograph with high resolution and color expression.

The light fastness of each color on the thermal transfer sheets of Examples 1, 2 and 3 and the light fastness of the heat-transferred image are JIS
7 to 8 grades were secured by each test method of L 0841 (fastness to sunlight), JIS L 0842 (fastness to dyeing with a carbon arc lamp), and JIS L 0843 (fastness to a xenon arc lamp).

Further, even if the thermal transfer sheet wound in a cylindrical shape was left at 60 ° C. for 96 hours at a constant temperature, blocking did not occur and the quality of the transferred image did not deteriorate.

Further, in a mutagenicity test (Ames-Test) known as a qualitative test on occupational safety and health, these thermal transfer sheets were safe and did not move as mutagens.

Claims (1)

[Claims] 1. A sublimation type color thermal transfer wherein one surface of a base material is sequentially coated with at least three types of ink layers of cyan, magenta and yellow, or four types of ink layers in which black is added to these hues. In the sheet, the sublimation dye constituting each of the cyan, magenta, yellow, and black ink layers is a strong light fastness dye, and these strong light fastness dyes are used in a single solvent or in a mixed solvent of two or more kinds. A sublimation type color thermal transfer sheet, characterized in that each ink is prepared by mixing two or more kinds.