JPH0834170A - Production of thermal sublimation type transfer sheet - Google Patents

Abstract

PURPOSE:To provide a thermal sublimation type transfer sheet having sufficient color forming properties and capable of forming an image having sufficient continuous gradation properties. CONSTITUTION:Ink for a dye layer prepared by substantially perfectly dissolving a sublimable dye and a binder resin in an org. solvent is applied to one surface of a base material sheet and dried to form a sublimable dye-containing layer on the surface of the base material sheet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a heat-sensitive sublimation type transfer sheet.

[0002]

2. Description of the Related Art Conventionally, a heat-sensitive sublimation type transfer sheet using a sublimable dye is prepared by adding a dye suitable for such a purpose into an ink vehicle containing a binder resin, and then using a grinding means such as a ball mill or a sand mill. Is prepared as finely dispersed as possible to prepare a dye layer ink, which is applied to a base sheet to form a dye layer having a predetermined thickness on the base sheet.

The heat-sensitive sublimation type transfer sheet thus obtained is superposed on an image receiving sheet having a dye receiving layer capable of receiving a dye, and from which side the image is formed by heating means such as a thermal head. A mono-color or full-color image is formed on the image-receiving sheet by heating the image-receiving sheet and sublimating the dye from the dye layer.

[0004]

The image forming method using the heat-sensitive sublimation type transfer sheet as described above has a problem that a specific image receiving sheet is used. However, for example, continuous gradation is obtained from an electric signal. It is possible to obtain a color image having the color image, and has been attracting attention in recent years. However, in the dye layer of the heat-sensitive sublimation transfer sheet, the sublimable dye is dispersed in the binder resin in the form of particles, and the heating time by the thermal head is only a few msec. In order to sublimate the dye molecules in such a state by heating, the interaction in the crystal is broken, and further heat energy exceeding the interaction with the binder resin is applied to the dye molecules to sublimate them and dye them on the image-receiving sheet. There must be.

Therefore, when a dye is contained in a high ratio with respect to the binder resin in order to obtain a high density color image requiring high energy, a high density image to some extent can be obtained. Due to the dispersed dye that is present at a high concentration, the binding force between the base sheet and the dye layer of the heat-sensitive sublimation type transfer sheet becomes weak, and when it is peeled off after printing with a thermal head etc. on the image receiving sheet, the dye layer However, the phenomenon that the binder resin together with the image receiving sheet is likely to occur,
Dyes are expensive in price, and from the viewpoint of OA equipment and home use, there are various drawbacks such that it is economically disadvantageous to add more dyes than necessary.

On the other hand, there has been proposed a method for obtaining a dye layer by coating a substrate sheet with a supernatant to dry the ink, which comprises a dye, a binder resin and a solvent, and drying it. In this case, the obtained dye layer may be one in which dyes are molecularly dispersed. In such a case, a higher concentration can be obtained with the same applied energy as compared with the dye layer.

However, in such a case, when the temperature becomes a little low in the state of the ink, the solubility of the dye is lowered, so that the concentration of the dye in the supernatant liquid is lowered and the ink is It lacks stability. Further, in an extreme case, there arises a problem that a dissolved dye is deposited mainly on the precipitated dye particles. Therefore,
An object of the present invention is to provide a thermal sublimation type transfer sheet which has a sufficient coloring property and can form an image having a sufficient continuous gradation.

[0008]

The above object can be achieved by the present invention described below. That is, the present invention is to apply a dye layer ink obtained by substantially completely dissolving a sublimable dye and a binder resin in an organic solvent onto one surface of a base sheet and dry it to obtain a base sheet surface. A method for producing a heat-sensitive sublimation transfer sheet, which comprises forming a sublimable dye-containing layer on.

[0009]

The present inventor, as a result of extensive research to solve the above-mentioned drawbacks of the prior art, adopted a combination of a specific binder resin, a specific sublimable dye and a specific solvent for the dye layer of the heat-sensitive sublimation transfer sheet. By forming it, the drawbacks of the prior art as described above are sufficiently solved, the heat-sensitive sublimation type transfer sheet has high stability, high thermal sensitivity, and continuous gradation as in direct silver salt photography and color development. It was found that an image such as a full curler photograph having sufficient property was obtained, and the durability of the obtained image was also sufficient.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to preferred embodiments. The main feature of the present invention is that when the dye layer ink is prepared using the sublimable dye, which is an essential component of the dye layer ink, the binder resin and the solvent, the dye and the binder resin are completely dissolved in the ink solvent. The essential components are selected and used in combination so as to maintain the dissolved state.

The first dye that characterizes the present invention is:
Any of the sublimable dyes that have hitherto been used for the heat-sensitive sublimation transfer sheet can be used, but those particularly preferred in the present invention are those having a small molecular weight of about 150 to 400, and the sublimation temperature, hue and light resistance. , The solubility in ink and binder resin, etc. are taken into consideration. Specifically, for example, those conventionally used as disperse dyes, and as preferable ones, Miketone Polyester Yellow YL (manufactured by Mitsui Toatsu, CI Dispers.
Yellow 42), Miketone, Polyester, Yellow 5
G (manufactured by Mitsui Toatsu, CI Disperse Yellow 5), Kayaset Yellow G (manufactured by Nippon Kayaku, CI
Solvent Yellow 77), Kayaset Yellow A
-N (Nippon Kayaku, CI Solvent Yellow 12)
5 (S)), PTY-52 (manufactured by Mitsubishi Kasei, CI Dispers Yellow 14-1), PTY-56 (manufactured by Mitsubishi Kasei, CI Dispers Yellow 3), Miketone Polyester Red BSF (Mitsui Toatsu, CI Dispers Red 111), Miketone Polyester Red T3B (Mitsui Toatsu, CI Dispers Red 228 (S)), Kayaset Red B (Nippon Kayaku) ,
C. I. Disperse Red 135), Kayaset Red 126 (Nippon Kayaku, CI Disperse Red 4), PTR-54 (CI Disperse Red 5)
0), PTR-63 (Mitsubishi Kasei, CI Disperse Red 60), Miketone Polyester Blue FBL
(Mitsui Toatsu, C.I. Disperse Blue 56), Discharge Blue R (Mitsui Toatsu, C.I. Disperse Blue 106), Mitsui PS Blue 3R (Mitsui Toatsu, C.I. Disperse Blue 33), PTB-6
7 (manufactured by Mitsubishi Kasei, CI Disperse Blue 24
1), PTB-77 (manufactured by Mitsubishi Kasei, CI Solvent Blue 90), Kayaset Blue 906 (manufactured by Nippon Kayaku,
C. I. Solvent Blue 112), Kayaset Blue 141 (Nippon Kayaku, CI Solvent Blue 114)
(S)) and the like.

Further suitable further dyes are sublimable basic dyes which have sufficient solubility in solvents, for example:
3,3'-diethyloxathiacyanine iodide, Astrazone Pink FG (manufactured by Bayer, C.I.
48015), 2,2'-carbocyanine (C.I.8).
08), Astrafiloxin FF (C.I.4807)
0), Astrazone Yellow 7GLL (CI Basic Yellow 21), Eisen Catillon Yellow 3G
Basic methine (cyanine) dyes such as LH (Hodogaya Chemical Co., CI 48055), Eisen Catillon Red 6BH (C.I.48020), monomethine, dimethine or trimethine; auramine ( C.I.
655) and the like basic dyes; malachite green (C.I. 42000), brilliant green (C.I. 42040), magenta (C.I. 42510), methyl violet (C.I.
I. 42535), crystal violet (C.
I. 42555), Methyl Green. (C.I. 68
4), Victoria Blue B (C.I. Dispers 0
45) and other triphenylmethane-based basic dyes; pyronin G (CI.739), rhodamine B (CI.451)
70), rhodamine 6G (C.I. 45160) and other xanthene-based basic dyes; acridine yellow G (C.I.
I. 785), Leonin AL (CI.46075),
Benzoflavin (C.I. 791), Affine (C.I.
I. Acridine-based basic dyes such as 46045); Neutral Red (CI.50040), Astrazone Blue BGE / × 125% (CI.51005),
Examples thereof include quinoneimine-based basic dyes such as methylene blue (CI.52015); and basic dyes such as anthraquinone-based basic dyes having a quaternary amine.

None of these dyes can be used freely, and it is necessary to select and use them in consideration of the relationship between the binder resin which is another essential component and the ink solvent. For example, with respect to the organic solvent selected as the ink solvent, for example, about 0.5 wt% or more for a yellow dye, about 1.0 wt% or more for a magenta dye, and about 2 wt% for a cyan dye. It should be selected to have a solubility of greater than or equal to 0.0% by weight.

As the binder resin used in the present invention, any conventionally known binder resin can be used for such purpose, and usually has high heat resistance,
Moreover, those that do not interfere with the migration of the dye when heated are selected, for example, as a cellulose resin, ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate butyrate, etc., as a vinyl resin, Examples thereof include polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl pyrrolidone, polyesters other than polyarylate, and polyacrylamide.

Such a binder resin is preferably selected as a binder resin that is substantially completely dissolved in the solvent and does not impair the solubility of the dye dissolved in the solvent in relation to the selected ink solvent described later. Is preferably used. Regarding the usage amount, for example, it is used at a ratio of about 50 to 1,000 parts by weight per 100 parts by weight of the dye, and the dye concentration when the dye layer is formed is about 5 to 80% by weight.
It is preferable to use it in a ratio such that

In the present invention, as the ink solvent for dissolving the above-mentioned dye and binder resin, a conventionally known ink solvent can be freely used. Specifically, as an alcohol solvent, methanol, ethanol, isopropyl alcohol, butanol, Isobutanol, etc., ketone-based methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc., aromatic-based toluene, xylene, etc., halogen-based dichloromethane, trichloroethane, etc.
Diquinane, tetrahydrofuran, etc., and mixtures of the above solvents are also mentioned. It is important to select and use these solvents so that the dye used is at a predetermined concentration or more and the binder resin is sufficiently dissolved.
For example, the total weight of the dye and the binder resin is about 2
It is preferred to use from 0 to 5 times the amount of solvent. The components as described above are essential components in the dye layer ink used in the present invention, and various conventionally known additives can be included in addition to these essential components.

The dye layer ink used in the present invention is mixed with the above-mentioned essential components and optional components added as necessary, and heated in various mixers as necessary,
It is obtained by simply dissolving the sublimable dye and the binder resin in the ink solvent, and does not require the grinding treatment which takes a long time as in the prior art. The dye layer ink used in the present invention obtained as described above, the components constituting them, particularly the dye and the binder resin are completely dissolved in the ink solvent, and the dissolved state is stably maintained. Since various components are selected and combined as described above, a stable dissolved state is maintained under normal conditions, and even when a dye layer is formed on a substrate sheet using the ink, the dye is The dye and binder resin are selected and combined so that they can be present in solution in the binder resin.

The dye layer ink used in the present invention described above has a dry weight of about 0.2 to 20 on one surface of the base sheet which may have a heat-resistant protective layer on the back surface thereof.
It is used to form a dye layer by coating so as to have a range of g / m ² , and examples of such a base sheet include condenser paper, polyester film, polystyrene film, polysulfone film, Papers or films such as polyimide film, polyvinyl alcohol film, cellophane, etc. may be mentioned, and the thickness thereof is 3 to 50 μm, preferably 3 to 15 μm. When price and heat resistance in untreated state are required among these papers and films, condenser paper is used.On the other hand, it has mechanical strength and handling and thermal treatment at the time of making a heat-sensitive sublimation transfer sheet. Polyester flume is preferably used when it is important that it does not break when it is run in the printer and that the surface is smooth.

[0020]

EXAMPLES Next, the present invention will be specifically described with reference to examples. In addition, in the text, parts are based on weight. Example 1 An ink for a dye layer used in the present invention was prepared using the following disperse dye, binder resin and solvent. Disperse dye (PTY-52, manufactured by Mitsubishi Kasei) 0.1 part Ethyl hydroxyethyl cellulose (manufactured by Hercules) 0.45 part Methyl ethyl ketone toluene (1/1) 9.45 parts The above ink for dye layer is completely transparent, No precipitate or aggregate was observed even after storage for 1 month at a temperature of 10 ° C. A heat-sensitive sublimation type transfer sheet was prepared by coating and drying the above ink for dye layer on a polyester film having a thickness of 9 μm, which was heat-treated on the back side, so that the dry weight was 0.4 g / m ² .

Next, a synthetic paper having a thickness of 150 μm (YUPO-FPG # 150, manufactured by Oji Yuka Co., Ltd.) was used as a base material, and an ink for a receiving layer having the following composition was coated with a wire bar to obtain a dry thickness of 4 g. and the image receiving sheet by coating / m to ² to become like. Drying is done temporarily with a dryer and then 1
It was carried out in an oven at 00 ° C for 1 hour to sufficiently evaporate the solvent. Byron 103 (Toyobo, polyester resin) 8 parts Elvalloy 741 (Mitsui Polychemical, EVA polymer plasticizer) 2 parts Amino-modified silicone oil (Shin-Etsu Silicone, KF-393) 0.125 parts Epoxy-modified silicone oil ( Shin-Etsu Silicone, X-22-343) 0.125 parts Toluene 70 parts Methyl ethyl ketone 10 parts Cyclohexanone 20 parts

Output of the thermal head by the thermal head from the support side of the heat-sensitive sublimation type transfer sheet so that the dye layer of the heat-sensitive sublimation type transfer sheet thus obtained and the receiving layer of the image receiving sheet are superposed on each other. 1 W / 1 dot, pulse width; 0.3-4.5 msec, dot density; 3 dots / mm, the result of recording was 4.5 ms pulse width.
The transfer density of the high density color development part of ec is 1.50,
Further, a portion having a pulse width of 0.3 msec was 0.26, and recording with gradation according to the applied energy was obtained (measuring instrument; Macbeth densitometer RD-918).

Example 2 An ink for dye layer was prepared using the following dye, binder resin and solvent. Disperse dye (KST-B-136, manufactured by Nippon Kayaku) 0.45 part Binder resin (polyvinyl butyral, SLEC-BX-1, manufactured by Sekisui Chemical) 0.45 part Methyl ethyl ketone / toluene / isobutanol (4.5 / 4) 0.5 / 1.0) 9.10 parts The above ink for dye layer was completely transparent and had good stability over time. Example 1 using this dye layer ink
Heat-sensitive sublimation type transfer sheet (dry coating amount 1.0
g / m ² ) and an image-receiving sheet were prepared and printed in the same manner, the reflection density was 1.90.

Example 3 An ink for a dye layer was prepared using the following dye, binder resin and solvent. Disperse dye (KST-Red-B, manufactured by Nippon Kayaku) 0.2 part Binder resin (polyester resin, Vylon 200, manufactured by Toyobo) 0.45 part Methyl ethyl ketone / toluene (1/1) 9.35 parts For the above dye layer The ink was completely transparent and had good stability over time. Example 1 using this dye layer ink
A heat-sensitive sublimation type transfer sheet and an image receiving sheet were prepared in the same manner as described above and printed in the same manner. The reflection density was 1.42.
Met.

Comparative Example 1 Disperse dye (KST-B-136, manufactured by Nippon Kayaku) 1.0 part Binder resin (ethyl cellulose N / 14, manufactured by Hercules) 3.0 parts Toluene / isopropyl alcohol (8/2) 7. 0 part When the above components were mixed, the dye and binder resin were not completely dissolved.
After milling for an hour, a dye layer ink for comparison was prepared. In the dye layer ink, a part of the dye was dissolved and the other was in a dispersed state. Then, the dye layer ink immediately after preparation was added to the ink 10
A heat-sensitive sublimation type transfer sheet was prepared using the dye layer ink stored at 0 ° C. for 1 month in the same manner as in Example 1, and the image receiving sheet of Example 1 was used under the same conditions as in Example 1. When printed, a phenomenon such as fusion of the dye layer to the receiving layer occurred, and the print density was 1.45 for the former and 1.35 for the latter, which was not satisfactory. The storage stability of the dye layer ink and the heat-sensitive sublimation transfer sheet using the dye layer ink are also insufficient.

[0026]

As described above, the dye in the dye layer of the heat-sensitive sublimation type transfer sheet obtained in the present invention is held in a state of being dissolved in the binder resin, so that it can be superposed on a conventionally known image-receiving sheet. From this aspect, by heating according to an image signal by a heating means such as a thermal head, the dye in the dye layer is easily transferred to the receiving layer of the image receiving sheet with relatively low energy according to the magnitude of heating energy, A color image with excellent sharpness and resolution gradation can be formed. When a heat-sensitive sublimation type transfer sheet using the dye layer ink used in the present invention is used, in the case of a heat-sensitive sublimation type transfer sheet similar to the conventional one, the dye in the dye layer is dispersed in a particulate form. Therefore, there are various problems as described above such that the transferability due to the heat of the thermal head is insufficient and non-uniform, and the background stain occurs due to the presence of the dye particles. Has been resolved.

Claims (4)

[Claims] 1. A substrate sheet surface is coated with a dye layer ink obtained by substantially completely dissolving a sublimable dye and a binder resin in an organic solvent and drying the ink to form a base sheet surface. A method for producing a heat-sensitive sublimation transfer sheet, which comprises forming a sublimable dye-containing layer. 2. The binder resin is ethyl cellulose,
At least one selected from the group consisting of a cellulose derivative selected from the group consisting of hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose and cellulose acetate butyrate, a vinyl resin, a polyacrylamide resin and a polyester resin other than polyarylate. The method for producing a heat-sensitive sublimation type transfer sheet according to claim 1. 3. The organic solvent is methanol, ethanol,
Alcohol solvents such as isopropyl alcohol, butanol, isobutanol, etc., ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.
The heat-sensitive sublimation transfer sheet according to claim 1, which is at least one selected from the group consisting of aromatic solvents such as toluene and xylene, halogen solvents such as dichloromethane and trichloroethane, and ether solvents such as diquinane and tetrahydrofuran. Manufacturing method. 4. When the organic solvent is a yellow dye, it is 0.
5% by weight or more, 1.0% by weight for magenta dyes
The method for producing a heat-sensitive sublimation transfer sheet according to claim 1, which has a solubility of 2.0% by weight or more in the case of a cyan dye.