JP2001260547A - Thermal transfer sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermal transfer sheet, with which a clear image having a high image density is formed by a sublimation type thermal transfer image forming method and, the light resistance and darkening and fading resistance of the image of which can be improved. SOLUTION: In the thermal transfer sheet 10A having a base material sheet 1, on one side of which a thermal transfer dye layer 2 is provided and on the other side of which a heat-resistant lubricating layer 4a is provided, a thermal transferring property stabilizer is included in the heat-resistant lubricating layer 4a or a thermal transferring property stabilizer layer 5 is formed on the surface of a heat-resistant lubricating layer 4b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer sheet using a sublimable or heat-diffusing dye (heat-migrating dye), and more particularly to a thermal transfer sheet for forming a transferred image having excellent light fastness and dark discoloration fastness. About.

[0002]

2. Description of the Related Art Conventionally, as one of image forming methods, a sublimation type thermal transfer image forming method is used in which a sublimable or heat diffusible dye is used as a recording agent and an image is formed by thermal transfer of the dye. More specifically, a thermal transfer sheet in which a thermal transfer dye layer made of a sublimable or thermally diffusible dye is supported on a base sheet such as a polyester film is used to transfer a dye-dyeable transfer material (for example, paper or plastic film). (A photographic paper on which a dye-receiving layer is formed) and heated by a thermal head of a printer to form an image on a material to be transferred. In addition,
Heating by the thermal head during printing is performed from the back of the thermal transfer sheet, but to prevent the thermal transfer sheet from fusing to the thermal head and to give the thermal transfer sheet smooth running properties, the thermal transfer sheet has a thermal transfer dye layer. A heat-resistant lubricating layer is provided on the surface opposite to the surface on which is formed.

According to the sublimation-type thermal transfer image forming method, a large number of color dots of three or four colors are transferred to a material to be transferred by heating in a very short time, and a full-color image of a document can be reproduced by these color dots. It becomes possible. Further, the image formed in this manner is very clear because the coloring material used is a dye, and is excellent in transparency. Therefore, similar to an image formed by conventional offset printing or gravure printing, reproducibility of intermediate colors and It is also possible to form a high-quality image that is excellent in gradation and comparable to a full-color photographic image.

[0004]

However, an image formed by a sublimation type thermal transfer image forming method generally has poor light fastness compared to an image formed by a pigment, and discoloration or change of the image when exposed to direct sunlight. There is a problem that is early.
Further, when direct light is not applied, for example, there is a problem that discoloration (dark discoloration and discoloration) occurs indoors, in a file, and even during binding of a book.

The problems of light fastness and dark discoloration can be alleviated to some extent by adding stabilizers such as ultraviolet absorbers and antioxidants to the dye receiving layer of the material to be transferred. However, in this method, the stabilizer is uniformly distributed throughout the dye-receiving layer of the material to be transferred, while the majority of the dye forming an image in the dye-receiving layer of the material to be transferred is present near the surface of the dye-receiving layer. Therefore, there is a problem that the dye cannot be efficiently protected by the stabilizer, and the discoloration prevention is insufficient.

[0006] To solve the problems of light fastness and dark discoloration, a stabilizer such as an ultraviolet absorber or an antioxidant is added to the thermal transfer dye layer of the thermal transfer sheet, and the stabilizer is coated simultaneously with the dye at the time of printing. There is also a method of transferring to a transfer material. However, according to this method, since a stabilizer is added to the thermal transfer dye layer of the thermal transfer sheet, problems such as a decrease in image density and crystallization of the dye occur.

Accordingly, the present invention provides a sublimation type thermal transfer image forming method which provides a clear image having a sufficient density, and more effectively protects the formed image with a stabilizer such as an ultraviolet absorber or an antioxidant. It is another object of the present invention to provide a thermal transfer sheet which imparts excellent fastness to images, particularly excellent light fastness and dark discoloration fastness.

[0008]

In order to achieve the above-mentioned object, the present invention provides a substrate sheet having a heat transfer dye layer on one surface and a heat-resistant lubricating layer on the other surface of the substrate sheet. In a thermal transfer sheet, there is provided a thermal transfer sheet in which a heat transferable stabilizer is contained in a heat-resistant lubricating layer.

The present invention also relates to a heat transfer sheet having a heat transfer dye layer on one surface of a base sheet and a heat resistant slip layer on the other surface of the base sheet. A thermal transfer sheet provided with a stabilizer layer is provided.

In general, in the process of manufacturing a thermal transfer sheet, a step of applying a thermal transfer dye layer and a heat-resistant lubricating layer to a base sheet, cutting the same, and rewinding the thermal transfer sheet into a roll while forming into a small wound product form. In the final product form, the thermal transfer sheet is stored in a wound state.
In the state where the thermal transfer sheet is wound, the thermal transfer dye layer and the heat-resistant lubricating layer are always in contact with each other, so that a part of the additives contained in the heat-resistant lubricating layer migrate to the thermal transfer dye layer.

On the other hand, according to the thermal transfer sheet of the present invention, the heat-resistant lubricating layer contains a heat-transferable stabilizer, or the thermal-transferable stabilizer layer is formed on the surface of the heat-resistant lubricating layer.
For this reason, in the state where the thermal transfer sheet is wound, the heat transferable stabilizer transfers to the thermal transfer dye layer from within the heat resistant slip layer or from the surface of the heat resistant slip layer, and the transferred thermal transfer stabilizer is used for the thermal transfer dye layer. Localizes to the surface. Therefore, at the time of printing, the heat transferable stabilizer is transferred to the image forming area of the transfer receiving material simultaneously with the sublimable or heat diffusible dye. Therefore, according to the thermal transfer sheet of the present invention, an image having excellent light fastness and dark discoloration fastness can be obtained.

When a stabilizer is contained in the thermal transfer dye layer of the thermal transfer sheet as in the conventional example, or when a stabilizer layer is provided on the surface of the thermal transfer dye layer, problems such as a decrease in image density and crystallization of the dye arise. However, according to the thermal transfer sheet of the present invention, since a stabilizer is contained in the heat-resistant lubricating layer, problems such as a reduction in image density and crystallization of dyes do not occur.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a thermal transfer sheet of the present invention will be described in detail with reference to the drawings. In each of the drawings, the same reference numerals represent the same or equivalent components.

FIG. 1 is a sectional view (FIG. 1 (a)) and a top view (FIG. 1 (b)) of one embodiment of a thermal transfer sheet of the present invention in which a thermal transfer stabilizer is contained in a heat-resistant lubricating layer. ).

The thermal transfer sheet 10A shown in FIG. 1 has a thermal transfer dye layer 2 composed of a sublimable or thermally diffusible dye and a binder, and a sensor mark 3 for a printer to detect the position of the thermal transfer sheet on one surface of a base sheet 1. Heat-resistant lubricating layer 4a containing a thermal transferable stabilizer on the other surface of the base sheet 1
have.

As the thermal transfer dye layer 2, color material layers 2Y, 2M and 2C for yellow, magenta and cyan are sequentially provided. In the present invention, the thermal transfer dye layer 2
The kind and order of the colors of the color material layers provided as above are not limited thereto. For example, only the black color material layer 2B may be provided as in the thermal transfer sheet 10C in FIG. 3, and further, the color material layers 2Y in four colors of yellow, magenta, cyan, and black as in the thermal transfer sheet 10D in FIG. , 2M, 2C, and 2B may be sequentially provided.

The dyes contained in the thermal transfer dye layer 2 include:
Known sublimation or heat diffusion dyes conventionally used for the dye layer of the thermal transfer sheet can be used. For example, as the yellow dye, azo, disazo, methine, styryl, pyridone azo and the like and a mixture thereof,
As magenta dyes, azo-based, anthraquinone-based, styryl-based, heterocyclic-based azo dyes and the like and their mixed systems, and as cyan dyes, anthraquinone-based, naphthoquinone-based, heterocyclic azo dyes, indoaniline-based and the like and mixed systems thereof Can be used.

As the binder carrying these dyes, known binder resins conventionally used for the dye layer of the thermal transfer sheet can be used. Examples of preferred binder resins include cellulose resins such as ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, cellulose acetate butyrate, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, and polyvinyl pyrrolidone. , A vinyl-based resin such as polyacrylamide, a polyester-based resin, and the like, in particular, a cellulose-based, an acetal-based,
Butyral and polyester are preferred.

The thermal transfer dye layer 2 may contain various additives which have been added to the conventional thermal transfer sheet dye layer.

The thermal transfer dye layer 2 is prepared by mixing the above-described dye, binder, and optional components and solvents added as needed to prepare a thermal transfer dye layer coating material, and applying the coating material on the base sheet 1. It can be formed by drying or curing.
The thickness of the thermal transfer dye layer 2 is preferably 0.5 to 1.5 μm.

On the other hand, as the substrate sheet 1, various known substrates conventionally used in thermal transfer sheets can be used. For example, polyester films, polystyrene films, polypropylene films, polysulfone films, polycarbonate films, polyimide films, aramid films and the like can be mentioned. The thickness of the base sheet 1 is preferably 1 to 30 μm,
-10 μm is more preferred.

The heat-resistant lubricating layer 4a is made of various lubricants, fillers, polyisocyanate compounds and the like and a binder resin for improving the running property and heat resistance of the base sheet 1 in the printer. The sheet 10A is characterized in that the heat-resistant lubricating layer 4a contains a heat transferable stabilizer.

Here, the thermal transfer stabilizer is a stabilizer that absorbs or blocks the action of light energy, heat energy, or the like that oxidizes, alters or decomposes the dye, thereby preventing oxidation, alteration, or decomposition of the dye. A material having thermal transferability that transfers from the heat-resistant lubricating layer to the thermal transfer dye layer by physical contact at normal temperature and transfers from the thermal transfer dye layer to the material to be transferred by being heated by the thermal head of the printer during thermal transfer. Say. The degree of this heat transfer property is preferably the same as the sublimation or heat diffusion dye used in the heat transfer dye layer, and more specifically, together with the sublimation or heat diffusion dye under heating conditions during thermal transfer. It is preferable that the transfer is performed to the transfer material.

Specific examples of the type of the heat transferable stabilizer include:
Examples include antioxidants, ultraviolet absorbers, light stabilizers and the like.

Examples of the antioxidant include a primary antioxidant such as phenol, monophenol, bisphenol, and amine, and a secondary antioxidant such as sulfur and phosphorus. As the antioxidant, commercially available products can be used. For example, Sumilizer BBN-S, Sumilizer BH
T, Sumilizer GM, Sumilizer MB, Sumilizer TPP-R (Sumitomo Chemical Co., Ltd.), Yoshinox 425, Yoshinox
SR (above, Yoshitomi Pharmaceutical), lrganox l081, lrganox-1222
(Above, Ciba-Geigy), Mark A0-40 (Adeka Argus Chemical Co., Ltd.) and the like which can be obtained from the market can be used.

Examples of the ultraviolet absorber include salicylic acid-based, benzophenone-based, benzotriazole-based, and cyanoacrylate-based ultraviolet absorbers. More specifically, Tinuvin P, Tinuvin 234, Tinuvin 320, Tinuvin 3
27 (above, Ciba Geigy), Sumisorb 110, Sumisorb 1
40 (or more, Sumitomo Chemical Co., Ltd.), Kemisorb 110, Kemisorb14
0, Kemisorb 10, Kemisorb 12, Kemisorb 13 (above, Kemipro Kasei), Uvinul X-19, Uvinul Ms-40 (above, BAS
Products available on the market under the trade names such as (F company), Tomisorb 100, Tomisorb 600 (all, Yoshitomi Pharmaceutical), Viosorb-80, and Viosorb-90 (all, Kyodo Yakuhin) can be used.

Examples of the light stabilizer include hindered amines. More specifically, Sanol LS-770, Sanol LS-765, Sanol LS774 (above, Sankyo), Sumisorb
A commercially available product such as TM-061 (Sumitomo Chemical Co., Ltd.) can be used.

The above heat transferable stabilizers can be used alone or as a mixture. The amount of the heat transferable stabilizer in the heat-resistant lubricating layer 4a is based on 100 parts by weight of the heat-resistant lubricating layer-forming resin.
It is preferred to be 5 to 50 parts by weight. If the amount is too small, the amount of the heat transferable stabilizer transferred from the heat-resistant lubricating layer 4a to the heat transfer dye layer 2 in a state in which the heat transfer sheet 10A is wound becomes small, and the effect of stabilizing the dye becomes insufficient. Conversely, if the amount of addition is too large, the friction reducing effect of the heat-resistant lubricating layer 4a becomes poor, and problems such as color misregistration and heat wrinkling occur.

The heat-resistant lubricating layer 4a can contain various lubricants, fillers, polyisocyanate compounds and the like used in the heat-resistant lubricating layer of the conventional thermal transfer sheet. For example, examples of the lubricant include a phosphoric ester compound, an organic silicone, polyethylene phenyl polysiloxane, a fatty acid amide, a fatty acid ester, a long-chain aliphatic compound, and a low-molecular-weight polypropylene. Among these, a phosphoric ester compound and an organic silicone are preferable.

Examples of the filler include inorganic fillers such as silica, talc, clay, zeolite, titanium oxide, zinc oxide, and carbon; silicone resin; and Teflon (registered trademark).
An organic filler composed of a resin, a benzoguanamine resin or the like can be used.

The polyisocyanate compound is not particularly limited as long as it has at least two isocyanate groups in the molecule. For example, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-xylene diisocyanate, hexamethylene diisocyanate, 4,4 '
Methylenebis (cyclohexylisocyanate), methylcyclohexane-2,4 (or 2,6) -diisocyanate, 1,3-di (isocyanatomethyl) cyclohexane, isophorone diisocyanate, trimethyl hexamethylene diisocyanate, or a mixture of diisocyanate and polyol Adduct of polyisocyanate (polyisocyanate prepolymer)
For example, an adduct obtained by reacting tolylene diisocyanate with trimethylolpropane can be used.

The binder resin used for forming the heat-resistant lubricating layer 4a is, for example, a polyester resin,
Polyacrylic ester resin, polyvinyl acetate resin, styrene acrylate resin, polyurethane resin, polyolefin resin, polystyrene resin, polyvinyl chloride resin, polyether resin, polyamide resin, polycarbonate resin, polyethylene Resin,
Examples of the resin include a polypropylene resin, a polyacrylate resin, a polyacrylamide resin, a polyvinyl chloride resin, a polyvinyl butyral resin, and a polyvinyl acetoacetal resin. Of these, polyvinyl butyral resin and polyacetoacetal resin are preferable.

FIG. 2 is a cross-sectional view of one embodiment of the thermal transfer sheet of the present invention in which a thermal transfer stabilizer layer is formed on the surface of the heat-resistant lubricating layer. This heat transfer sheet 10B is different from the heat transfer sheet 10A of FIG. 1 in that the heat-resistant lubricating layer 4b does not contain a heat-transferable stabilizer in the layer, and the heat-transferable stabilizer layer 5 is formed, and the other configuration is the same as that of the thermal transfer sheet 10A in FIG.

The heat transferable stabilizer layer 5 can be formed by preparing a coating solution by mixing the above-mentioned heat transferable stabilizer and a solvent, coating the solution on the heat-resistant lubricating layer 4b, and drying.

The layer thickness of the heat transferable stabilizer layer 5 is from 0.1 to
It is preferably 0.5 μm. If it is too thin, the amount of the thermal transfer stabilizer transferred from the thermal transfer stabilizer layer 5 to the thermal transfer dye layer 2 while the thermal transfer sheet is wound becomes small, and the effect of stabilizing the dye becomes insufficient. On the other hand, if the thickness is too large, the effect of reducing friction of the heat-resistant lubricating layer 4b is not sufficiently exhibited, and problems such as color shift and wrinkles are undesirably generated.

The thermal transfer sheet of the present invention can be used as long as the heat-resistant lubricating layer contains a heat-transferable stabilizer or a heat-transferable stabilizer layer is formed on the surface of the heat-resistant lubricating layer. In addition to the above, various embodiments can be adopted. For example, as shown in FIG. 5, on the substrate 1, in addition to the thermal transfer dye layer 2 (2Y, 2M, 2C), a transparent transfer protective layer which is transferred to the printing screen after printing and protects the printing screen. 6 may be provided. Further, as shown in FIG. 6, a transfer type receiving layer 7 which is transferred to plain paper in advance before printing may be provided. The transfer-type receiving layer 7 is a layer corresponding to a dye-receiving layer of a transfer-receiving material such as thermal transfer printing paper. Even if the transfer material is plain paper, a good transfer image can be obtained.

[0037]

The present invention will be described more specifically with reference to test examples.

1. Test example of heat-resistant lubricating layer containing ultraviolet absorber or light stabilizer (1-1) Preparation of dye layer sheet for evaluation of discoloration and fading Using a 6 μm thick polyester film (Toray Co., Ltd. The following ink composition of Table 1 was dried at a thickness of 1 μm.
Thus, a dye layer was formed to obtain a dye layer sheet for evaluating discoloration and fading.

[0039]

Table 1 Ink composition Dye: Disperse Violet 26 5.0 parts by weight Polymer: Polyvinyl butyral resin (BX-1 manufactured by Sekisui Chemical Co., Ltd.) 5.0 parts by weight Methyl ethyl ketone 45.0 parts by weight Toluene 45.0 parts by weight

(1-2) Preparation of heat-resistant lubricating layer sheet for evaluation A 6 μm-thick polyester film (Lumirror manufactured by Toray Industries, Inc.) was used as a base material. A heat-resistant lubricating layer was formed by coating to a thickness of 1 μm to obtain a heat-resistant lubricating layer sheet for evaluation.

[0041]

[Table 2] Composition resin for heat-resistant lubricating layer : 5.0 parts by weight of Table 3 Lubricant: 2.0 parts by weight of isocyanate compound (Coronate-L manufactured by Nippon Polyurethane Industry Co., Ltd.) 0.5 part by weight Silica (Nipsil E- manufactured by Nippon Silica Industry Co., Ltd.) 200A) 0.5 parts by weight Thermal transfer stabilizer (ultraviolet absorber or light stabilizer): Table 3 X parts by weight Methyl ethyl ketone 46-X / 2 parts by weight Toluene 46-X / 2 parts by weight Table 2 Note X = [in Table 3 Numerical value of stabilizer addition amount (parts by weight)] × 0.05

(1-3) Preparation of Thermal Wrinkle Evaluation Sheet A 6 μm thick polyester film (Lumirror manufactured by Toray Industries Co., Ltd.) was used as a base material, and a heat-resistant lubricating layer was formed on one surface thereof in the same manner as in (1-2) above. To form a dye layer on the other side in the same manner as (1-1),
A sheet for evaluation of hot wrinkles was obtained.

(1-4) Evaluation (1-4a) Heat-resistant lubricating layer sheet formed with photobleaching rate (1-2) (Test Examples 1 to 3 in Table 3)
(8) having a heat-resistant lubricating layer of (8), and (1-1)
Overlay the dye layers of the dye layer sheet formed in (2)
0 cm) Press machine (PY-5EA type heating / cooling molding machine, Kodaira Seisakusho)
, A load of 1 t was applied at a temperature of 25 ° C for 24 hours. After pressing, cut and paste the dye layer sheet on the magenta part of the ribbon of UPC1010 (print media for UP-1800, manufactured by Sony Corporation).
Step printing was performed on UPC1010 photographic paper with a P-1800 (Sony) printer. The density immediately after printing (OD = around 1.0) was measured with a Macbeth densitometer (TR-924, Green filter). After the concentration measurement, Xe was irradiated with 90000 KJ with a xenon long life weather meter (Suga Test Instruments Co., Ltd.), the OD was measured again with a Macbeth densitometer, and the photobleaching ratio was determined by the following formula.

[0044]

## EQU1 ## Photofading rate (%) = (OD ₀ −OD ₁ ) / OD ₀ ×
100 (%) OD ₀ : Reflection density of print immediately after printing OD ₁ : Reflection density of print after light irradiation

Further, based on the numerical value of the photobleaching rate, the photofading rate was evaluated in four steps according to the following criteria. Table 3 shows the results
Shown in ：: light fading rate ≦ 20 ：: 20 <light fading rate ≦ 30 Δ: 30 <light fading rate ≦ 35 ×: 35 <light fading rate

(1-4b) Hot wrinkle A heat-resistant lubricating layer of the hot wrinkle evaluation sheet formed in (1-3),
Lay the dye layers of the dye layer sheet formed in (1-1),
Press in the same manner as (1-4a), then cut and paste the thermal transfer sheet for thermal wrinkle evaluation on the magenta part of the ribbon of UPC1010, and print it on the printing paper of UPC1010 with the printer of UP-1800 in solid black, Hot wrinkles were visually inspected. Table 3 shows the results.
In the table, ○ indicates that no hot wrinkle was observed, and x indicates the case where hot wrinkle was observed.

[0047]

[Table 3] Table 3 Note (* i) Parts by weight per 100 parts by weight of binder resin for heat-resistant lubricating layer (* 1) Polyvinyl butyral resin: manufactured by Denki Kagaku Kogyo Co., Ltd. Tenkokachiral # 6000EP (* 2) Polyvinyl butyral resin: manufactured by Denki Kagaku Kogyo Tinkafutilal # 5000-A (* 3) Polyacetoacetal resin: Sekisui Chemical Co., Ltd.
ESREC KS-5 (* 4) Polyvinyl butyral resin: Sekisui Chemical Co., Ltd.
Esrec BX-1 (* a) Phosphate: Plysurf A manufactured by Toho Chemical Co.
208S (* b) Organic silicone: KF-60 manufactured by Shin-Etsu Chemical Co., Ltd.
03 (* c) Phosphate ester: Phosphanol ML-200 manufactured by Daiichi Kogyo Seiyaku Co., Ltd. (* d) Organic silicone: KF-60 manufactured by Shin-Etsu Chemical Co., Ltd.
04 (* A) UV absorber: Tinuvi manufactured by Ciba Geigy
n234 (* B) UV absorber: Chemiso, manufactured by Chemipro Kasei
rb10 (* C) UV absorber: Yoshitomi Pharmaceutical Co., Ltd. Tomisorb 100 (* D) Light stabilizer: Sankyo LS-770 (* E) Light stabilizer: Sumitomo Chemical Co., Ltd.
TM-061

From the results shown in Table 3, it can be seen that when the heat-resistant lubricating layer contains an ultraviolet absorber or a light stabilizer, the photobleaching ratio is reduced and the light resistance is improved. In particular, when 5 to 50 parts by weight of an ultraviolet absorber or a light stabilizer is contained with respect to 100 parts by weight of the binder resin of the heat-resistant lubricating layer, the light resistance is remarkably improved,
In addition, it can be seen that there is no generation of thermal wrinkles due to the increase in friction.

2. Test example of heat-resistant lubricating layer containing antioxidant (2-1) Preparation of dye layer sheet for evaluating discoloration and discoloration Obtaining dye layer sheet for evaluating discoloration and discoloration in the same manner as in (1-1) above. Was.

(2-2) Preparation of heat-resistant lubricating layer sheet for evaluation In the preparation of the heat-resistant lubricating layer sheet of (1-2) described above, Table 2 was used.
As the resin, lubricant, and heat transferable stabilizer of Table 4, instead of those shown in Table 3, those described in Table 4 were used. A heat-resistant lubricating layer sheet for evaluation was formed by forming a heat-resistant layer.

(2-3) Preparation of Thermal Wrinkle Evaluation Sheet A 6 μm-thick polyester film (Lumirror, manufactured by Toray Industries, Inc.) was used as a base material. To form a dye layer on the other surface in the same manner as (2-1),
A sheet for evaluation of hot wrinkles was obtained.

(2-4) Evaluation (2-4a) Dark heat discoloration rate Heat-resistant lubricating layer sheet formed at (2-2) (Test Examples 9 to
A heat-resistant lubricating layer having 16 heat-resistant lubricating layers) and (2-
Overlay the dye layers of the dye layer sheet formed in 1),
× 20 cm) A press (PY-5EA type heating / cooling molding machine, Kodaira Seisakusho) was applied with a load of 1 t at a temperature of 25 ° C. for 24 hours.
After pressing, the dye layer sheet is replaced with UPC1010 (Sony, UP-180
(0 print media) was cut and pasted on the magenta portion of the ribbon, and step-printed on a UPC1010 photographic paper using a UP-1800 (manufactured by Sony Corporation) printer. Density immediately after printing (OD = 1.0
(Nearby) was measured with a Macbeth densitometer (TR-924, Green filter). After the density measurement, the sample was stored at 65 ° C. and a humidity of 50% for one week, the OD was measured again with a Macbeth densitometer, and the dark discoloration rate was calculated by the following formula.

[0053]

## EQU2 ## Dark discoloration rate (%) = (OD ₀ −OD ₂ ) / OD ₀
× 100 (%) OD ₀ : Reflection density of print immediately after printing OD ₂ : Reflection density of print after storage

Further, based on the numerical values of the dark discoloration / fading rate, the dark discoloration / fading rate was evaluated in four steps according to the following criteria. Table 4 shows the results. ：: Dark discoloration rate ≦ 5 ○: 5 <Dark discoloration rate ≦ 15 Δ: 15 <Dark discoloration rate, ≦ 20 ×: 20 <Dark discoloration rate,

(2-4b) Hot wrinkle A heat-resistant lubricating layer of the hot wrinkle evaluation sheet formed in (2-3),
Except for pressing the dye layers of the dye layer sheet formed in (2-1), the presence or absence of hot wrinkles was examined in the same manner as in the evaluation of hot wrinkles in (1-4b). Table 4 shows the results.

[0056]

[Table 4] Table 4 Note (* i) Parts by weight per 100 parts by weight of binder resin for heat-resistant lubricating layer (* 1) Polyvinyl butyral resin: manufactured by Denki Kagaku Kogyo Co., Ltd. Tinkafutilal # 5000-A (* 3) Polyacetoacetal resin: Sekisui Chemical Co., Ltd.
ESREC KS-5 (* 4) Polyvinyl butyral resin: Sekisui Chemical Co., Ltd.
Esrec BX-1 (* a) Phosphate: Plysurf A manufactured by Toho Chemical Co.
208S (* b) Organic silicone: KF-60 manufactured by Shin-Etsu Chemical Co., Ltd.
03 (* c) Phosphate ester: Phosphanol ML-200 manufactured by Daiichi Kogyo Seiyaku Co., Ltd. (* d) Organic silicone: KF-60 manufactured by Shin-Etsu Chemical Co., Ltd.
04 (* F) Antioxidant: Sumiliz manufactured by Sumitomo Chemical Co., Ltd.
er BHT (* G) Antioxidant: Yoshinox SR (* H) Antioxidant: manufactured by Yoshitomi Pharmaceutical Co., Ltd .: Irganox manufactured by Ciba-Geigy
-1222 (* I) Antioxidant: Mark manufactured by Adeka Argus Chemical Company
A0-40 (* J) Antioxidant: Sumiziz manufactured by Sumitomo Chemical Co., Ltd.
er GM

From the results shown in Table 4, it can be seen that when an antioxidant is contained in the heat-resistant lubricating layer, the dark discoloration / fading rate decreases and the dark discoloration / fading resistance improves. In particular, when the antioxidant is contained in an amount of 5 to 50 parts by weight based on 100 parts by weight of the binder resin of the heat-resistant lubricating layer, the resistance to dark discoloration and discoloration is remarkably improved, and there is no generation of wrinkles due to an increase in friction. You can see that.

3. Test example of heat-resistant lubricating layer having a stabilizer layer (ultraviolet absorber or light stabilizer) on its surface (3-1) Preparation of dye layer sheet for evaluation of discoloration and discoloration A dye layer sheet for fading evaluation was obtained.

(3-2) Preparation of heat-resistant lubricating layer sheet for evaluation A polyester film (Lumirror manufactured by Toray Industries Co., Ltd.) having a thickness of 6 μm was used as a base material. A heat-resistant lubricating layer is formed by coating so as to have a thickness of 1 μm, and a stabilizer layer in which an ultraviolet absorber or a light stabilizer shown in Table 6 is dispersed or dissolved in an organic solvent (MEK / TOL) is further formed thereon. The coating liquid for application was applied with a coil bar to form a stabilizer layer having a thickness shown in Table 6 after drying, and a heat-resistant lubricating layer sheet for evaluation was obtained.

[0060]

[Table 5] Composition resin for heat-resistant lubricating layer : 5.0 parts by weight of Table 6 Lubricant: 2.0 parts by weight of isocyanate compound (Coronate-L manufactured by Nippon Polyurethane Industry Co., Ltd.) 0.5 part by weight Silica (Nipsil E- manufactured by Nippon Silica Industry Co., Ltd.) 200A) 0.5 parts by weight Methyl ethyl ketone 46.0 parts by weight Toluene 46.0 parts by weight

(3-3) Preparation of Thermal Wrinkle Evaluation Sheet A 6 μm-thick polyester film (Lumirror, manufactured by Toray Industries, Inc.) was used as a base material, and a stabilizer was applied to one surface in the same manner as in (3-2) above. A heat-resistant lubricating layer having a layer was formed, and a dye layer was formed on the other surface in the same manner as in (3-1) to obtain a sheet for evaluating thermal wrinkles.

(3-4) Evaluation (3-4a) Photobleaching Rate The heat-resistant lubricating layer of the heat-resistant lubricating layer sheet formed at (3-2) (Table 6)
Test Examples 17 to 24 in which a stabilizer layer was formed on the surface) and the dye layer of the dye layer sheet formed in (3-1) were superimposed and pressed. In the same manner as in the evaluation of the fading rate, the light fading rate of the print was obtained, and the light fading rate was evaluated on a four-point scale. Table 6 shows the results.

(3-4b) Hot wrinkle A heat-resistant lubricating layer of the hot wrinkle evaluation sheet formed in (3-3),
Except for the overlapping of the dye layers of the dye layer sheet formed in (3-1) and pressing, the presence or absence of hot wrinkles was examined in the same manner as in the evaluation of hot wrinkles in (1-4b). Table 6 shows the results.

[0064]

[Table 6] Table 6 Note (* 1) Polyvinyl butyral resin: Denka Chemical Co., Ltd. Tenkokachiral # 6000EP (* 2) Polyvinyl butyral resin: Denka Chemical Co., Ltd. Tenkokachiral # 5000-A (* 3) Polyacetoacetal resin: Sekisui Chemical Industrial company
ESREC KS-5 (* 4) Polyvinyl butyral resin: Sekisui Chemical Co., Ltd.
ESREC BX-1 (* 5) Polyacetoacetal resin: Sekisui Chemical Co., Ltd.
Esrec KS-5 (* a) Phosphate: Price Surf A manufactured by Toho Chemical Co.
208S (* b) Organic silicone: KF-60 manufactured by Shin-Etsu Chemical Co., Ltd.
03 (* c) Phosphate ester: Phosphanol ML-200 manufactured by Daiichi Kogyo Seiyaku Co., Ltd. (* d) Organic silicone: KF-60 manufactured by Shin-Etsu Chemical Co., Ltd.
04 (* A) UV absorber: Tinuvi manufactured by Ciba Geigy
n234 (* B) UV absorber: Chemiso, manufactured by Chemipro Kasei
rb10 (* C) UV absorber: Yoshitomi Pharmaceutical Co., Ltd. Tomisorb 100 (* D) Light stabilizer: Sankyo LS-770 (* E) Light stabilizer: Sumitomo Chemical Co., Ltd.
TM-061

From the results shown in Table 6, it can be seen that when a stabilizer layer comprising an ultraviolet absorber or a light stabilizer is formed on the surface of the heat-resistant lubricating layer, the light fading rate is reduced and the light resistance is improved. In particular,
It can be seen that when the thickness of the stabilizer layer made of an ultraviolet absorber or a light stabilizer is 0.1 to 0.5 μm, the light resistance is remarkably improved, and no thermal wrinkles are generated due to an increase in friction.

4. Test example of heat-resistant lubricating layer having a stabilizer layer (antioxidant) on its surface (4-1) Preparation of dye layer sheet for discoloration evaluation Discoloration evaluation for discoloration evaluation in the same manner as (1-1) above A dye layer sheet was obtained.

(4-2) Preparation of heat-resistant lubricating layer sheet for evaluation In the preparation of heat-resistant lubricating layer sheet for evaluation in (3-2) above, the ultraviolet ray absorption shown in Table 6 was used to form the stabilizer layer. A stabilizer layer composed of an antioxidant was formed using the antioxidant shown in Table 7 instead of the agent or the light stabilizer, to obtain a heat-resistant lubricating layer sheet for evaluation.

(4-3) Preparation of Thermal Wrinkle Evaluation Sheet A 6 μm thick polyester film (Lumirror manufactured by Toray Industries, Inc.) was used as a base material, and one surface of the film was protected from oxidation by the same method as described in (4-2) above. A heat-resistant lubricating layer having a stabilizer layer made of an agent was formed, and a dye layer was formed on the other surface in the same manner as in (4-1) to obtain a sheet for evaluating thermal wrinkles.

(4-4) Evaluation (4-4a) Dark heat discoloration rate The heat resistant slip layer of the heat resistant slip layer sheet formed according to (4-2) (Table 7)
Test Examples 25 to 32 in which a stabilizer layer was formed on the surface) and the dye layer of the dye layer sheet formed in (4-1) were overlapped and pressed, except that the darkening of (2-4a) was performed. In the same manner as in the evaluation of the fading rate, the dark discoloration rate of the print was determined, and the dark discoloration rate was 4%.
It was rated on a scale. Table 7 shows the results.

(4-4b) Hot wrinkle A heat-resistant lubricating layer of the hot wrinkle evaluation sheet formed in (4-3),
Except for the overlapping of the dye layers of the dye layer sheet formed in (4-1) and pressing, the presence or absence of hot wrinkles was examined in the same manner as the evaluation of hot wrinkles in (1-4b). Table 7 shows the results.

[0071]

[Table 7] Table 7 Notes (* 1) Polyvinyl butyral resin: Denka Chemical Co., Ltd. Tenkokachiral # 6000EP (* 2) Polyvinylbutyral resin: Denka Chemical Co., Ltd. Tenkokachiral # 5000-A (* 3) Polyacetoacetal resin: Sekisui Chemical Industrial company
ESREC KS-5 (* 4) Polyvinyl butyral resin: Sekisui Chemical Co., Ltd.
Esrec BX-1 (* a) Phosphate: Plysurf A manufactured by Toho Chemical Co.
208S (* b) Organic silicone: KF-60 manufactured by Shin-Etsu Chemical Co., Ltd.
03 (* c) Phosphate ester: Phosphanol ML-200 manufactured by Daiichi Kogyo Seiyaku Co., Ltd. (* d) Organic silicone: KF-60 manufactured by Shin-Etsu Chemical Co., Ltd.
04 (* F) Antioxidant: Sumiliz manufactured by Sumitomo Chemical Co., Ltd.
er BHT (* G) antioxidant: Yoshinox SR (* H) antioxidant: manufactured by Yoshitomi Pharmaceutical Co., Ltd .: Irganox manufactured by Ciba-Geigy
-1222 (* I) Antioxidant: Mark manufactured by Adeka Argus Chemical Company
A0-40 (* J) Antioxidant: Sumiziz manufactured by Sumitomo Chemical Co., Ltd.
er GM

From the results shown in Table 7, it can be seen that when a stabilizer layer comprising an antioxidant is formed on the surface of the heat-resistant lubricating layer, the dark discoloration / fading rate is reduced and the dark discoloration / fading resistance is improved. In particular, when the thickness of the stabilizer layer made of the antioxidant is 0.1 to 0.5 μm, the dark discoloration resistance and the discoloration resistance are remarkably improved, and it can be seen that there is no generation of heat wrinkles due to an increase in friction.

[0073]

According to the thermal transfer sheet of the present invention, an image formed by a sublimation type thermal transfer image forming method is formed with high image density and sharpness, and the image is formed by a stabilizer such as an ultraviolet absorber or an antioxidant. More effective protection can be imparted to the image, and excellent light fastness and dark discoloration fastness can be imparted to the image.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view and a top view of a thermal transfer sheet of the present invention.

FIG. 2 is a cross-sectional view of the thermal transfer sheet of the present invention.

FIG. 3 is a top view of the thermal transfer sheet of the present invention.

FIG. 4 is a top view of the thermal transfer sheet of the present invention.

FIG. 5 is a top view of the thermal transfer sheet of the present invention.

FIG. 6 is a top view of the thermal transfer sheet of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Base material sheet, 2 ... Thermal transfer dye layer, 2Y ... Yellow color material layer, 2M ... Magenta color material layer, 2C ... Cyan color material layer, 2B ... Black color material layer, 3 ... Sensor mark,
4a: a heat-resistant lubricating layer containing a thermal transferable stabilizer, 4b
... heat-resistant lubricating layer, 5 ... thermal transfer stabilizer layer, 6 ... transfer protective layer, 7 ... transfer type receiving layer 10A, 10B, 10C, 10D ... thermal transfer sheet

Claims (6)

[Claims] 1. A heat transfer sheet having a heat transfer dye layer on one side of a base sheet and a heat-resistant slip layer on the other side of the base sheet, wherein a heat transfer stabilizer is contained in the heat-resistant slip layer. Thermal transfer sheet. 2. The thermal transfer sheet according to claim 1, wherein the thermal transferable stabilizer has the same thermal transferability as a sublimable or thermally diffusible dye contained in the thermal transfer dye layer. 3. The thermal transfer sheet according to claim 1, wherein the thermal transferability stabilizer is contained in the heat-resistant lubricating layer in an amount of 5 to 50 parts by weight based on 100 parts by weight of the heat-resistant lubricating layer-forming resin. 4. A heat transfer sheet having a heat transfer dye layer on one surface of a substrate sheet and a heat resistant slip layer on the other surface of the substrate sheet, wherein a heat transfer stabilizer layer is provided on the surface of the heat resistant slip layer. The formed thermal transfer sheet. 5. The thermal transfer sheet according to claim 4, wherein the thermal transfer stabilizer forming the thermal transfer stabilizer layer has the same thermal transfer property as a sublimable or thermally diffusible dye contained in the thermal transfer dye layer. 6. The layer thickness of the heat transferable stabilizer layer is from 0.1 to 0.1.
The thermal transfer sheet according to claim 4, wherein the thickness of the thermal transfer sheet is 5 μm.