JPH0339293A - Sheet to be recorded for thermal transfer - Google Patents

Abstract

PURPOSE:To form a sheet to be recorded not fused to an ink ribbon by providing a dyeing layer containing a specific saturated polyester resin, a polyisocynate compound and a specific surfactant to the surface of a base material sheet. CONSTITUTION:A coating solution is prepared by dissolving and dispersing a saturated polyester resin (A) having an ester forming component having a bisphenol A skeletal in a polymer main chain and having glass transition temp. of 60 deg.C or higher, polyisocyanate (B) and a water-insoluble surfactant (C) containing a fluorinated alkyl group in an org. solvent. This coating solution is applied to a base material sheet such as papers, synthetic paper or a film and dried to laminate a dyeing layer receiving a dye to form a sheet to be recorded for thermal transfer. It is pref. to respectively compound (B) and (C) in amounts of 5 - 25% and 2 - 15% by wt. of (A).

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a recording sheet for thermal transfer, and more specifically, it has excellent receptivity to sublimable dyes during thermal transfer, does not fuse with the thermal transfer ribbon, and is stable. A recording sheet capable of thermal transfer is placed between the recording sheets.

<Prior art and its problems> In recent years, with the spread of televisions, VTRs, video discs, personal computers, etc. as information processing terminals, and the spread of methods for displaying various information on CRT displays, these images have become color images. Various recording methods have been proposed for recording. One such method is the dry heat transfer recording method, which has attracted much attention in recent years because it can be easily controlled by electrical signals, is noiseless, and is easy to maintain. This dry heat transfer recording method is
A color ink ribbon is combined with a recording sheet, and the ink in the ink ribbon is heated by an electric signal and is transferred by melting or sublimation transfer to a thermal transfer device, the amount of which is emitted is controlled by an electric signal, to create images, etc. This is a method of recording information.

This dry heat transfer method includes a heat melt transfer type and a sublimation transfer type.

The thermal melt transfer type uses an ink ribbon in which dyes or pigments are dispersed and mixed in a thermoplastic resin, wax, etc., and receives heat from a thermal head to transfer and solidify a hot melted ink layer onto a recording sheet. However, although this method uses a simple device and can achieve a relatively high recording speed, it has drawbacks such as a reduction in brightness due to color mixing in the case of color images and difficulty in reproducing halftones.

The other type, the sublimation transfer type, uses an ink ribbon coated with a binder resin mixed with a disperse dye with high sublimation stability, and receives heat from a thermal head to transfer the dye in the ink ribbon onto the recording sheet. This is a sublimation transfer method.

With this method, it is easy to obtain heating tonality according to the ripening energy, and the sublimation of the dye corresponds to the transfer of the dye on the molecular order, so it is easy to control the image quality of intermediate gradations, and the brightness and A high-density image can be obtained. Therefore, this method is considered to be the most suitable method for applications such as video printers, full color printers, Victorian color proofs, and color copiers.

The ink ribbon used in this method has a thermal transfer ink layer in which a sublimable disperse dye is mixed with wax, polyester resin, polyamide resin, polyolefin resin, etc. on the surface of a polyethylene terephthalate film or the like. On the other hand, the recording sheet used is a sheet of plain paper, synthetic paper, plastic film, cloth, etc., on which a receiving layer to which dye can be fixed is provided. However, when the base material is plain paper, there are problems such as poor surface smoothness, poor image resolution, low color density, and insufficient dye fixability and durability. For this reason, synthetic papers and films such as polyester, polypropylene, polystyrene, and polyamide,
Copolymerized polyester, polyamide, etc. with a low glass transition temperature that can effectively dye sublimation dyes on the surface of foam sheets, etc.
Those provided with a thermoplastic resin layer such as polystyrene are used. However, during printing, the temperature of the thermal head reaches 300 to 400'C, and the recording sheet becomes soft due to ripening. There are problems in that both the ink ribbon and the recording sheet are fused together, making it impossible to run, or abnormal transfer of ink occurs, resulting in unnecessary unevenness on the recording sheet, resulting in a reduction in image quality. For this reason, a method has been proposed in which granular fillers such as titanium oxide, silica, calcium carbonate, and talc are added to the soybeans to form unevenness on the surface of the dyeing layer in order to prevent heat-induced fusion. Therefore, stable transfer of the sublimable dye was not performed, and it was difficult to obtain images with high resolution.

Furthermore, when forming a dyeing layer containing highly cross-linked and heat-resistant resins such as silicone resins, epoxy resins, and melamine resins, the penetrating dyeability of sublimation dyes decreases, resulting in a high concentration of dyes. Image reproduction was difficult. For this reason, a method has been proposed in which a low surface energy layer of silicone resin, fluororesin, etc. is layered on top of the dyeing layer. This may lead to a loss of flatness on the surface of the dyeing layer, making it difficult to print with high resolution.Also, low energy resins such as silicone resins and fluororesins are incompatible with the dyeing layer resin. Therefore, a sea-island structure or a mottled structure is formed on the surface, and it is difficult to completely prevent the ink ribbon and the recording sheet from fusing together.
It has been difficult to obtain high-quality images due to uneven shading in printed images.

<Objective of the Invention> The object of the present invention is to provide a sublimation transfer recording method that does not cause fusion between the ink ribbon and the recording sheet, enables stable printing, provides high print density, and improves image storage and durability. The purpose of the present invention is to provide a recording sheet with excellent properties.

Another object of the present invention is to provide a recording sheet that has excellent resolution in addition to the above characteristics.

<Structures and Effects of the Invention> According to the present invention, an object of the present invention is to provide a recording sheet for thermal transfer, which comprises a base sheet and a dyed layer for receiving a dye formed on at least one side of the base sheet. The attached layer comprises (A) a saturated polyester resin having an ester-forming component having a bisphenol A skeleton in the polymer main chain and a glass transition temperature of 60°C or higher, (B) a polyisocyanate compound, and (C1 water-insoluble This is achieved by a recording sheet for thermal transfer, which is characterized in that it is a layer containing a surfactant containing a fluorinated alkyl group.

The dyed layer in the present invention comprises (A) a saturated polyester resin having an ester-forming component having a bisphenol A skeleton in the polymer main chain and having a glass transition temperature of 60°C or higher, (B) a polyisocyanate compound, and (C) Contains a water-insoluble surfactant containing a fluorinated alkyl group.

Saturated polyester resin<A+ is preferably a linear saturated polyester resin, especially one or more dicarboxylic acid components and one or more diol components (however, in the case of - type of dicarboxylic acid component, two or more diol components are used). A reacted non-grade copolymerized polyester is preferred. The molecular weight of this saturated polyester resin is 5000-50.000
is preferred. This saturated polyester resin (A) has an ester-forming component having a bisphenol A skeleton in the polymer main chain, and the proportion of the ester-forming component in the polymer is preferably 5 to 25% by weight. By introducing an ester-forming component having a bisphenol A skeleton into the polymer main chain, advantages can be obtained in terms of penetration of disperse dyes, dyeability, solubility in organic solvents, heat resistance (high glass transition temperature), etc. However, if the above ratio is less than 5% by weight, the dyeability of the disperse dye will be low and it will be difficult to obtain sufficient image density.On the other hand, if it exceeds 25% by weight, it will be difficult to produce a highly polymerized polymer and the image will fade. This is undesirable because the saturated polyester resin has a large color transfer and transfer of the dye, which may significantly impair the properties of the recording sheet.The acid component of such a saturated polyester resin includes aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid. Acid, 2゜6-naphthalene dicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, etc. and aliphatic dicarboxylic acid, such as adipic acid, sepacic acid, etc.; Preferably, the acid is mainly used.

Diol components include aliphatic glycols such as ethylene glycol, tetramethylene glycol, neopentyl glycol, diethylene glycol, etc., polyalkyl ether glycols such as polyethylene ether glycol and polytetramethylene ether glycol, and aromatic diols such as hydroquinone, Resorcinol, bisphenol S, bisphenol A [2,2
-bis(4-hydroxyphenol)propane], their alkylene oxide adducts (e.g. 2,2-bis(4-hydroxyphenol)propane);
-hydroxyethoxyphenyl)propane, 2,2-bis(4-hydroxypropoxyphenyl)propane, etc.>
For example, it is necessary to include bisphenol A or its alkylene oxide adduct. Further, since the saturated polyester resin (A) is required to have a glass transition temperature of 60° C. or higher, consideration must be given to this point when selecting the combination of the acid component and the diol component.

The saturated polyester resin +A) can be produced by a known method such as a melt polymerization method or a solution type method, but this method is preferably selected based on the reaction characteristics of the ester-forming compound having a bisphenol A skeleton. For example, when bisphenol A is used as it is, a solution polymerization method in which it is reacted with an acid halide is preferred, and when an ethylene oxide adduct of bisphenol A is used, a melt polymerization method (eg, transesterification method) is preferred.

As mentioned above, the saturated polyester resin (A) is required to have a glass transition temperature of 60°C or higher, but if the glass transition temperature is lower than 60°C, the heat resistance and storage stability will be low, and there will be problems such as color transfer and bonding between sheet surfaces. This is undesirable because it causes blocking and also tends to cause blurring, blurring, blurring, etc. of printed characters during thermal transfer recording.

Next, as the polyisocyanate compound Th(B), diisocyanate, triisocyanate, etc. are used alone or in combination. For example, paraphenylene diisocyanate, 1-chloro-24-phenyl diisocyanate,
2-chloro-1,4-phenyl diisocyanate, 2.
4-) Luene diisocyanate, 2.6-), Luene diisocyanate, Hexamethylene diisocyanate, 4
, 4'-biphenylene diisocyanate, xylene diisocyanate, metaphenylene diisocyanate, 2.
Specific examples include 4,6-triphenyl isocyanate, and further adducts of the above-mentioned isocyanate compounds with trimethylolpropane, glycerin, phenol, caprolactam, and the like. Particularly preferred among these are toluene diisocyanate, xylene diisocyanate and metaphenylene diisocyanate. The combined use of this polyisocyanate compound is particularly useful in preventing color transfer of dyes. Generally, when printed recording sheets are piled up or wound up into a roll, the dye in the dyed layer gradually migrates, causing a color transfer phenomenon.This tendency is particularly noticeable in high temperature and high humidity environments. Although this is likely to occur, it is thought that the use of a polyisocyanate compound in combination promotes partial crosslinking of the saturated polyester resin constituting the dyed layer, thereby reducing dye migration. The amount of the polyisocyanate compound used is 5 to 25 parts by weight, more preferably 7.5 to 25 parts by weight, per 100 parts by weight of the saturated polyester resin.
Preferably, it is 15 parts by weight. If the amount of the polyisocyanate compound is less than 5 parts by weight, the color transfer of the dye will be severe, resulting in poor long-term storage stability, while if it exceeds 25 parts by weight, the proportion of polynisder resin, which is a dyeable resin, will be small. This is not preferable because sufficient image density cannot be obtained. Furthermore, the use of polyisocyanate compounds has a remarkable effect on the adhesion between the base sheet and the dyed layer, especially in that the adhesion is not lost even when stored under high temperature and high humidity.

Furthermore, the water-insoluble fluorinated alkyl group-containing surfactant (C) is a surfactant containing a hydrophilic group such as a carboxylate, a phosphate, a polyoxyalkylene adduct, or an ester compound thereof, with respect to a hydrophobic group such as a fluorocarbon. It is of type II construction. Such a surfactant is present in the dyeing layer, and preferably at least a portion thereof is distributed on the surface layer, and forms a release surface when it comes into contact with the ink ribbon, thereby preventing fusing, abnormal transfer, and poor running of the ink ribbon. It has the function of preventing In the structure of this surfactant, especially the polyoxyalkylene adduct and its ester compound are involved in the affinity and compatibility with the saturated polyester resin + A) in the dyeing layer, and the H ,L.

n (Hydrophile - Lipophile
When Ba1ance) is larger than 7, the surfactant is incorporated into the saturated polyester resin (A), and migration to the surface layer of the dyeing layer is small, resulting in insufficient components on the release surface and often resulting in poor melting of the ink ribbon. I am sorry for the inconvenience of wearing it. On the other hand, when H, L, and B are smaller than 5,
Since the compatibility of the surfactant with the saturated polyester resin decreases, migration to the surface layer of the dyeing layer occurs over time, and a sufficient mold release surface is formed. Also H,
For those with L, , , B = 5 to 7, migration is extremely small when left alone, but at 40 to 80 °C
A stable release surface can be formed on the surface layer of the dyed layer by heating the dyed layer to a temperature of .

The surfactant used in the present invention preferably has H, L, and B of 7 or less, but all of these are water-insoluble surfactants that do not have a solubility in water of 0.5% or more at room temperature. It is. If the hydrophilic group is a carboxylate, phosphate, etc. other than polyoxyalkylene adducts and their ester compounds, a preferable mold release surface can be formed if the hydrophilic group is water-insoluble. If it is used, the releasability of the surface of the dyeing layer will be insufficient, making it impossible to avoid fusion of the ink ribbon.

Examples of fluorocarbons forming the hydrophobic group of the surfactant include CF34 CF 2 CF 2 +-5CF3÷CF2
Examples include fluorine-containing compounds such as polyvinyl fluoride, polyvinylidene fluoride, and vinyl fluoride-vinylidene copolymer represented by CFH+0, CF3+CFHCFH+, and the like. The degree of polymerization (b) of these compounds is 2 to 2
0, preferably 4-10. - In general, with a low degree of polymerization, it is difficult to uniformly form the low energy surface of a fluorine compound and to exhibit mold release and slipping effects.
On the other hand, for compounds with a degree of polymerization exceeding 20,
Solvent solubility as a surfactant becomes insufficient, which is not preferable.

As a specific example of a water-insoluble fluorinated alkyl group-containing surfactant, the trade name Surflon S-141, 145
<Made by Asahi Glass ■), Megafac ■F-183184 (manufactured by Dainippon Ink Chemical Industry 0 Vermilion), Florado ■PC-43
1 (manufactured by Sumitomo 3M ■), etc.

In dry heat transfer, the runnability, ink transfer, fusion, etc. between the ink ribbon and recording sheet during image recording are largely related to the interfacial tension, friction coefficient, etc. of the surface layer of the dyed layer.

Therefore, it is necessary for the surface layer of the dyed layer of the recording sheet to form a low-energy interface, but the surfactant (C) migrates inside the dyed layer to the surface layer and forms this low-energy interface. Form. The thickness of the layer (releasing layer) forming this interface is preferably 50 to 200. If the thickness exceeds 200 mm, dye migration during transfer will be hindered and only low-density images will be obtained. Furthermore, in this case, an undesirable phenomenon is observed in which the dye that has been dyed once migrates back into the release layer of the surfactant, increasing color transfer, bleeding, etc. On the other hand, if the thickness of the release layer is less than 5OA, the ink ribbon and the recording sheet will fuse together during image recording, resulting in extremely unfavorable conditions such as poor running. This is considered to be because the amount of mold release agent was insufficient and a sufficiently uniform low energy interface was not formed.

In order to form a release layer with such thickness, it is preferable that the proportion of the surfactant (C1) is in the range of 2 to 15% by weight (based on the saturated polyester resin).

If this proportion is less than 2% by weight, the release layer is insufficiently formed, resulting in fusion and poor running of the ink ribbon. On the other hand, 15
If it exceeds a serious degree, the image density during transfer will be low, the storage stability of the dyed image will be reduced, color transfer will increase, and the properties of the recording sheet may be significantly impaired, which is not preferable.

Next, as a method for migrating the surfactant (C1) in the dyeing layer to the surface layer, methods such as radiation treatment with infrared rays, far infrared rays, electron beams, etc., vacuum treatment, pressure treatment, etc. are also used on the dyeing layer. However, the most preferable method is to leave it in an atmosphere at a temperature of 30 to 80°C for several hours to several days to form a release layer and form a two-layer structure with the dyed layer.
If the temperature is below 0°C, it is difficult to form a complete release layer even if left for a long time, and when an image is transferred, the ink ribbon may partially fuse. On the other hand, if it is exposed to a temperature exceeding 80'C, the surface properties and flatness of the film will deteriorate, and the uniformity of the release layer will be lost, causing density unevenness during image transfer, which is undesirable.

Furthermore, this release layer needs to have a uniform surface, and if it has a partial seabird structure or mottled pattern, it is likely to cause fusion with the ribbon, and it will be difficult to achieve high resolution. . Therefore, the dyed layer in the present invention is uniformly applied onto the base sheet using a coating method such as a high-precision reverse roll coater, gravure coater, Meyer bar coater, microgravure coater, air knife coater die coater, or spray coater. It is preferable to form the film by drying it.

In addition to the above-mentioned components (A), CB+, and (C), the dyed layer in the present invention contains an antistatic agent, if necessary.
Ultraviolet absorbers, fluorescent agents, anti-sticking agents, waxes, fillers, matting agents, surface tension adjusters, etc. can be added.

The thickness of the dyed layer after coating and drying is preferably 1.0 to 1.0.
6.0 μm, more preferably 2.0 to 4.0 μm
It is. The dyed layer of the present invention has a particularly high ability to fix dyes, so there is no need for a thick dyed layer like conventional ones, and sufficient image density can be obtained with a film thickness that is about half that of conventional ones, making it even clearer. You can get a good image. However, the film thickness is 1.0μ
If it is less than 6.m, sufficient image density cannot be obtained.
If it exceeds 0 μm, no further improvement in image density is observed and there is almost no economic advantage.

Next, examples of the base sheet according to the present invention include various papers made of cellulose fibers, synthetic papers made of plastic resin, and films (see 1 to 1). Among these, from the viewpoint of heat resistance, 10μ
Achieving excellent resolution and high image density on the order of m,
The stretched film 11 is preferably made of aromatic polyester, such as polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, etc., from the viewpoint of not causing deformation of the base sheet due to heat during image formation.

The aromatic polyester stretched film can be obtained by a method in which the aromatic polyester is melt-formed to form an unstretched film, and then the unstretched film is further biaxially stretched and oriented and fixed at high temperature. I can do it.

These polyester films are usually 1.35 to 1-4
It has a film density of 2 gl'cm', but by forming micro cavities (voids) inside, the film density is reduced to 1.10.
Low-density polyester films of ~1°35 g/cm3 can also be used.

However, if the film density is less than 1.10 g/cm3, there will be too many mMA cavities, resulting in a decrease in heat resistance and mechanical strength, and the film will lose its desirable properties as a recording material.

Although polyester film can be used alone,
If necessary, two or more sheets may be bonded together, or other substrates such as plain paper, coated paper, synthetic paper, film, metal foil, etc. may be bonded together. Also, as a base sheet,
Coated paper, art paper, synthetic paper, plastic sheets such as vinyl chloride, polypropylene, etc. can be used alone or in combination of two or more of these sheets bonded together. In this case, although some games are slightly inferior in terms of resolution and the like compared to polyester base sheets, they have exactly the same excellent characteristics in terms of image density, image stability, etc. The thickness of the base sheet is usually 25 to 500 mm. tz+n.

The thermal transfer recording sheet of the present invention enables smooth conveyance printing without causing fusion with the ink ribbon during printing by the addition of a thermal head, and also achieves high image density and photo-like printing. It is possible to form images with excellent resolution and sharpness, and even after printing, the dyed image has a strong chemical bond between the release layer and the dye molecules in the dyeing layer, which suppresses the diffusion and migration of the dye. It has the characteristics of being stably protected by the heat and being able to withstand long-term storage.

<Example> The present invention will be described below with reference to Examples. In addition, part 1 of the text
"" means parts by weight. In addition, the thickness of the release layer in the text can be measured by changing the irradiation angle of the ESCA.
The film thickness was measured using a calibration curve to determine the absorption intensity of atoms. This is called the ESCA bending method in the text.

Example 1 8.0% by weight of calcium carbonate with an average particle size of 0.5 μm,
Intrinsic viscosity (orthochlorophenol, 35°C) containing 3.0% by weight of titanium oxide with an average particle size of 0.3μm
>0.60 polyethylene terephthalate at 285°C
The mixture was melted at 50°C and skewered onto a cooling drum at 50°C. The obtained sheet was stretched 3.5 times in the longitudinal direction at 80°C, then 3.4 times in the transverse direction at 110°C, and further fixed to form a polyester film with a thickness of 125 μm and a specific gravity of 1.40. This was used as a base sheet.

On the other hand, 8145 parts of dimethyl terephthalate, 110.4 parts of dimethyl isophthalate, and 45 parts of ethylene glycol.
5 parts, neopentyl glycol 20.2 parts, 22 bis(
4~hydroxyethoxyphenyl> 144 parts of propane,
0.05 part of antimony oxide and 0.05 part of zinc acetate dihydrate
A portion of the mixture was charged into a transesterification reactor, and the temperature began to rise. When the liquid temperature in the reaction tank reached 170°C, distillation of methanol began. After reacting for about 5.0 hours, about 95% of the theoretical amount of methanol was distilled out. Therefore, the liquid temperature in the reaction tank was raised, and when it reached 220'C, 0.5 parts/10 of trimethyl phosphate was added thereto, and the reaction liquid was sent to a polymerization reaction tank under an inert atmosphere.

The temperature of the reaction solution placed in the polymerization reaction tank was 221℃ and 4B.
Also. Immediately after putting the receiver in, the temperature begins to rise, and after 1.45 minutes, the temperature rises to 2.
Reached 58℃ 1. i. During this period, the reaction is at normal pressure.

Next, after the temperature of the liquid inside the reaction tank reached 260℃, the degree of vacuum inside the chamber was gradually lowered to 0.3 mmHg0 absolute pressure in 30 minutes.
0: Allow the air to reach the empty state and raise the liquid temperature to 275°C,
The industrial F rangericol and other glycols were distilled off. When the polycondensation reaction was continued in this state for about 2 hours, a viscous saturated polynisder resin was obtained.

The intrinsic viscosity of this polymer 0 is 0.58, and the glass layer f
The Z point (F3°) was reached.

Next, this saturated polynisder resin was heated and dissolved in a mixed solvent of methyl ethyl tetone, , , 7 rhene <30'70 parts> to obtain a polyester resin solution having a solid fraction concentration of 20% by weight.

100 parts of this polynisder resin solution, 2 parts of modified isocyanate (70 Nate 02030, 50% solids, 8 bottles of polyurethane industry), polyoxyethylene ethanol adduct of perfluorocarbon (Servlon S-
145, solid content 30%, Asahi Glass> 7.5 parts, fine silica (Aerosil R972, - Hon Aerosil) 0.05 parts,
71,720 parts of methyl ethyl, 25 parts of toluene and 5 parts of cyclohexanone were mixed and stirred for 30 minutes to prepare a dyed FgJ paint. The viscosity of this paint is ZahnCUP R2
The time was 23.5 seconds (24°C).

This paint was applied to one side of the polyester base sheet 1 using a reverse roll coater so that the coating amount after drying was 3 g/'-. The thickness of the dyed layer was 3.1 μm.

Next, the n-ru film coated with the dyed layer was left in a dryer at 50°C for 72 hours to undergo heat treatment.

After treatment, the film thickness of the release layer on the surface layer of dye layer 5 was measured using the ESCA angle method and was found to be 145.
Cut to size m, use dye sublimation printer Hitachi video printer VY-100, use ink ribbon S-100
), thermal head recording conditions were 6 dots/mm, printing voltage was 044 W/' dots, and when printing a gradation pattern by changing the impression pulse width, fusion, abnormal transfer, poor running, etc. occurred. The images were printed smoothly, and as shown in Table 1, images with excellent clarity and high density were obtained.

In addition, when this print was overlaid with a coat and coat under a pressure of 6 kg in a 60" CX 85% RH mountain atmosphere and the transfer status was examined, there was no bleeding, fading, transfer, etc. in the image. It showed extremely good storage stability.

1, Absolute Example 2], the dyeing layer paint was replaced with a polyoxyethylene ethanol adduct of perfluorocarbon ester compound PC-43.
1. 6.0 parts of Sumitomo 3M (solid content 50%)
: A recording sheet was prepared in the same manner as in Example except that the paint was changed. As a result of printing tests using these recording sheets 1 to 1, no fusion, abnormal transfer, or running defects occurred.
A clear, high-density image can be obtained.

Example 3 The polyester resin component of the dyed layer was 117.4 parts of dimethyl terephthalate, and 76.6 parts of dimethyl isophthalate.
parts, 61.8 parts of styrene glycol and 2,2-bis<
4-hydroxye↑・xyphenyl)propa〉'148
A recording sheet was prepared in the same manner as in Example 1, except for changing to a polynisder resin obtained by reacting 2 parts. The results of a printing test using this recording sheet showed that fusion,
There were no abnormal transfers or poor running, and clear, high-density images were obtained.

Example 4 The coating composition of the dyed layer was 100 parts of the polyester resin solution prepared in Example 3, 1 to 2.5 parts of modified isothiaphor (Tagenate ■A-12, solid content bog, Takeda Pharmaceutical Co., Ltd.), Ultraviolet absorber (JUNOX [F] 2000, Morisawa Shoji) 0.2 parts, polyether modified dimethylsiloxane (B
YK ■-30, BYK-Chemie) 1.2 parts, barfluoro cocarbon' ester (Florado ■FC-
431, solid content 50%, Sumitomo 3M), 5.5 parts of methyl ethyl getone, 20 parts of toluene, and 5 parts of cyclohexanone to prepare a paint.

A recording sheet was prepared using this paint in the same manner as in Example 1. The thickness of the release layer was measured using the ESCA bending method and was found to be 80.

When printing was evaluated using the obtained recording sheet in the same manner as in Example 1, it was found that a clear, high-density image with excellent storage stability was obtained without causing any fusion, abnormal transfer, or poor running.

Example 5 Using the polyester resin for the dyed layer used in Example 2, 100 parts of the polyester resin solution and modified isocyanate (
N-3030, solid content 60%, Japan Polyurethane Industries>
2 parts, polyoxyethylene ethanol adduct of perfluorocarbon (Surflon S-145, solid content 30%
, Asahi Glass) 10 parts, ultraviolet absorber (Viosorb■5
50, Kyodo Yakuhin> 0.2 parts, 20 parts of methyl ethyl ketone, 25 parts of toluene and 5 parts of cyclohexanone are blended,
A paint for the dyed layer was prepared.

Apply this paint to a transparent polyester film (Kijin Tetron Film HS Type, 1) using a reverse roll coater.
00] It was coated on top of 1) so that the coated area after drying was 3.0 g/pot. The thickness of the dyed layer was 2.8 μm.

This coated sheet was left in an oven at 70°C for 30 seconds and then held in a roll at 40°C for 2 days.

When printing was evaluated using the obtained recording sheet in the same manner as in Example, clear and high-density images were obtained without any fusion, abnormal transfer, or poor running.

Example 6 A recording sheet was prepared in the same manner as in Example 1 except that the fine particles containing polyethylene terephthalate were changed to 11.0% by weight of titanium oxide having an average particle diameter of 0.3 μm. When printing was evaluated using this recording sheet in the same manner as in Example 1, a clear, high-density image was obtained without fusion, abnormal transfer, or poor running.

Comparative Example A recording sheet was prepared by forming a dyed layer using a polyester resin that does not contain a bisphenol A skeleton. That is, 104.8 parts of dimethyl terephthalate, 89.2 parts of dimethyl isophthalate, and 47.5 parts of ethylene glycol.
81% J and 62.4 parts of neopentyl glycol
A saturated polyester resin having an intrinsic viscosity of 0.63 and a glass transition temperature of 67°C was obtained by reacting in the same manner as in Example 1, and a recording sheet was prepared in the same manner as in Example 1, except that this polyester resin was used as the dyeing layer component. did. When this sheet was evaluated in the same manner as in Example 1, it was found that the image density of the fused image was low, and that the gradation in particular at low gradations and the maximum density of printing in a high-temperature atmosphere were insufficient. Ta.

Comparative Example 2 As the saturated polyester resin of the dyed layer, 73.7 parts of dimethyl terephthalate and 120 parts of dimethyl isophthalate were used.
3 parts of ethylene glycol, 47.2 parts of ethylene glycol, 58.5 parts of neopentyl glycol, and 15.2 parts of 2,2'-bis(4-hydroxyethoxyphenyl)propane.
Intrinsic viscosity 0.61. A polyester resin having a glass transition temperature of 58°C was prepared. A recording sheet using this polyester for the dyed layer was prepared in the same manner as in Example 1. When printing was carried out using this sheet in the same manner as in Example], the image density was generally at a good level, but
Color transfer and bleeding were significant in the χRH atmosphere, and unsatisfactory results were obtained in terms of storage stability.

Comparative Example 3 A recording sheet was prepared in the same manner as in Example 1 using the dyed layer coating composition of Example 1 except for the modified isocyanate (Coronate L, solid content 75?≦, Nippon Polyurethane Industries). Created. When this sheet was used in the same printing test as in Example 1, the image density was good, but there was significant color transfer and bleeding in an atmosphere of 60°C x 80% RH, and the results were unsatisfactory in terms of storage stability. I couldn't get it. Furthermore, the adhesion of the coating film was also insufficient.

Comparative Example 4 Implementation WJ 1 dyeing layer coating j 2 I spicy and 6 father 1 inside? ,
A recorded sheet neat was prepared in the same manner as in Example 1 using perfluorocarbon polyoxyethylene except for ethanol (Surflon S-145, solid content 30?A, Asahi Glass). Example 1 using this sheet
After the same heat treatment, print test? □- When the ink ribbon was 0 stiff, it could not run and was printed. (7) Evaluation of Examples and Comparative Examples show,. The evaluation method for I3 and J3 for each example is as shown in IJ below.

Measuring method: (1) Print 'IS' properties: Prepare a print sheet as a recording seed for thermal transfer, cut out the print sheet into a size of 10 cm x 12 □ 7 cm 2, and use a back leather type printer or Hitachi video printer VY.
100, the ink ribbon used (S-100), the recording conditions of the thermal head were 6 dots/'mrn, and the printing voltage was 11.
．． A gradation pattern was printed at 5 V by changing the applied pulse width. Fusing between the ink ribbon and the recording material during print recording (2) Abnormal transfer, poor running J) If there is no such problem, it is rated as ○, and if there is even the slightest abnormality, it is rated as N.

(2) Image (@Characteristics: The image density of the image of the print sample was measured using a Macbeth densitometer Rr)-918, and the change in density corresponding to the printing pulse width was evaluated as gradation ε. The image density is evaluated by the maximum density, and the gradation is evaluated by the slope of the density corresponding to the pulse width by gradation and l, and 'v! , those with higher values were considered good. j Sat/1:: Regarding the sharpness of the image, observe with a microscope δyt to see if the thin line parts are uniformly connected. , Some parts are defective △
, If the dots were not uniform and the dots were cut off, it was rated as ×.

(3) Color transfer: Printed on fS test paper and coated paper (OKr
9. Temperature 60°C,
A load of 6 kg/- was applied and left for 24 hours in an atmosphere with humidity of 80% RH. The density of the transferred dye on the coat/paper after standing was measured using a Macbeth densitometer RD-918, and the color shift was evaluated as 1. The higher the density, the worse the color transfer, and the lower the density, the better. It was determined that

Furthermore, regarding the bleeding property, we observed under a microscope whether the size of the dots in the gray gale part of the 50% halftone were lined up in a uniform size. Those with unclear surrounding boundaries were marked as ×.

(4) Fading property: The surface of the printed sample was irradiated with carbon arc light (Sasshi Shine Fade Meter 5EL-1 Suga test@machine), and the fading rate at 0 cyan density was determined after 24 hours.

It was determined that the smaller the 0 value, the better the fading property, and the larger the 0 value, the worse the fading property.

(−> marks are not measured.

Claims (4)

[Claims] (1) A recording sheet for thermal transfer comprising a dye-receiving layer formed on at least one side of a base sheet, wherein the dye-layer has (A) a bisphenol A skeleton in the polymer main chain; (B) a polyisocyanate compound, and (C) a water-insoluble fluorinated alkyl group-containing surfactant. A recording sheet for thermal transfer characterized by being a layer. (2) Based on the weight of (A) saturated polyester resin, (B
) 5 to 25% by weight of a polyisocyanate compound, (C)
2. The recording sheet for thermal transfer according to claim 1, wherein the amount of the surfactant is in the range of 2 to 15% by weight. (3) The recording sheet for thermal transfer according to claim 1 or 2, wherein the proportion of the ester-forming component having a bisphenol A skeleton in the saturated polyester resin (A) is in the range of 5 to 25% by weight based on the total weight of the polymer. (4) Heat-treating the recording sheet for thermal transfer to (C) transfer and diffuse a water-insoluble fluorinated alkyl group-containing surfactant onto the surface of the dyeing layer to a thickness of 50 to 200 Å to form a two-layer structure. The recording sheet for thermal transfer according to claim 1, 2 or 3.