JPH0514636B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a transfer recording method. More specifically, the present invention relates to a new transfer recording method comprising a specific dye and a recording medium using a specific compound. 2. Description of the Related Art In OA terminals such as facsimile printers and copying machines that have become rapidly popular in recent years, there is an increasing demand for color recording that contains a large amount of information and is easy to read visually. On the other hand, it is desired to develop a technology for recording television images in color. Currently, color recording techniques using electrophotography, inkjet, and thermal transfer systems are being considered for these purposes. Among these methods, the thermal transfer method is advantageous over other methods because the device is easy to maintain and operate, and the device and consumables are inexpensive. Thermal transfer methods include the melting method, in which an ink layer formed on a base film is heated and melted using a heat-sensitive bed, and then transferred and recorded onto a recording medium; There is a sublimation method, which uses heat to sublimate the dye and transfer it onto the recording medium.
Since the amount of sublimation transfer of the dye can be controlled, gradation recording is easy and it is considered to be particularly advantageous for full-color recording. By the way, in order to reduce the load on the heat-sensitive head and increase the recording speed, it is desirable that the dye used here be one that sublimates as easily as possible; This is undesirable because during long-term storage or in a high-temperature, high-humidity environment, the dye re-sublimes from the recording medium, deteriorating the recording, or transfers to objects that come in contact with it, causing contamination. Currently, as a method to solve this problem, it is being considered to prevent re-sublimation by laminating the surface of the recording medium with a resin film after transfer recording. However, such a method requires materials and equipment for laminating, and the entire equipment becomes larger and more complicated, so further improvements are desired. An object of the present invention is to provide a method for obtaining a transcription record with excellent storage stability. That is, the present invention provides a method for performing transfer recording by heating a transfer sheet coated with a dye with a heat-sensitive recording head to transfer the dye to a recording medium. A dye containing a hydrogen atom is used, and a compound having an epoxy group, an isocyanate group, or a blocked isocyanate group is used for the recording material, and the dye in the transfer sheet is used to absorb the epoxy groups in the recording material during transfer. The gist thereof is a transfer recording method characterized in that a dye is fixed by reacting with a compound having an isonianate group or a blocked isocyanate group. Examples of dyes that react with epoxy groups or isocyanate groups include azo, anthraquinone, naphthoquinone, styryl, and nitro dyes having groups such as amino groups, alkylamino groups, hydroxyl groups, carboxyl groups, amide groups, and mercapto groups;
There are methine-based and quinophthalone-based dyes, and specific examples include dyes with the following structures. Examples of the compound having an epoxy group include various known epoxy group-containing polymers or epoxy group-containing monomers, and specific examples thereof include the following. Various known isocyanate compounds can be used as the compound having an isocyanate group, but
Specific examples include the following. No.205 OCN−(CH ₂ ) ₆ −NCO Examples of compounds having blocked isocyanate groups include compounds in which isocyanate groups are formed by heating during thermal transfer. Specific examples include compounds obtained by inactivating (masking) the above-mentioned isocyaneno compounds with ethanol, phenol, cresol, diethyl maleate, ethyl acetoacetate, acetylacetone, and the like. Next, I will explain how to create a transfer sheet.
The above pigment may be mixed with a suitable resin, solvent, water, etc. to prepare an ink, and the ink may be applied onto a suitable base material and then dried. As the resin for preparing the above ink,
Oil-based resins such as rosin-based, phenol-based, xylene-based, petroleum-based, vinyl-based, polyamide-based, alkyd-based, nitrocellulose-based, alkylcellulose-based, cellulose ester-based, etc., may be used in ordinary printing inks. Alternatively, aqueous resins such as maleic acid, acrylic acid, casein, silk, and glue can be used. In addition, solvents for ink preparation include alcohols such as methanol, ethanol, propanol, and butanol, solosolves such as methyl cellosolve and ethyl cellosolve, aromatics such as penzene, toluene, and xylene, and ethyl acetate and butyl acetate. Esters, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexane, hydrocarbons such as ligroin, cyclohexane, and kerosene, and dimethylformamide can be used, but when using a water-based resin, water or water-based resins may be used. It is also possible to use a mixture of the above solvents. Substrates for applying ink include condenser paper, thin paper such as glassine paper, polyester,
Plastic films with good heat resistance such as polyamide and polyimide are suitable, but these substrates need to be thin to improve the efficiency of heat transfer from the heat-sensitive recording head to the dye, and the thickness must be 50 μm or less. is suitable, and preferably 20 μm or less. Next, a method for creating a recording medium will be described. The above-mentioned isocyanates, blocked isocyanates, and epoxy compounds may be used alone or in a mixture, mixed with a suitable resin and solvent, coated on a suitable substrate, and dried. The same resins and solvents as in the case of preparing the transfer sheet are used, but those that react with isocyanates, blocked isocyanates, and epoxy compounds cannot be used. As the resin, in addition to those mentioned in the adjustment of the ink of the transfer sheet, linear polyester resins, acrylic ester resins, polycarbonate resins, and the like can also be used. As the base material used here, in addition to paper, various resin films or synthetic papers made from them can also be used. To perform thermal transfer recording using the transfer sheet and recording medium described above, the ink-coated surface of the transfer sheet is overlapped with the coated surface of the recording medium, and the transfer sheet is heated from the back side with a thermal recording head. All you have to do is apply pressure. When transfer recording is performed by the above method, the dye in the transfer sheet is sublimated and transferred to the recording medium, and at the same time, the dye is mixed with a compound having an epoxy group, an isocyanate group, or a blocked isocyanate group in the recording medium. Through the reaction, the dye is fixed, and records with excellent storage stability can be obtained. As is clear from the above explanation and the examples described later, records with excellent storage stability can be easily obtained by the present invention. EXAMPLES The present invention will be specifically explained below with reference to Examples, but these Examples are not intended to limit the present invention. Reference Example 1 (Synthesis of dye of Example 1) The following structural formula Dissolve 62.1g of the compound represented by in 420mg of IPA (isopropyl alcohol),
Add 19.8g and 1.5ml of piperidine, raise the temperature to 80℃,
The reaction was carried out at 80°C for 2 hours. After cooling, add methanol, filter the precipitated crystals, wash with water, and after drying, yellow crystals
Obtained 62g. The maximum absorption wavelength (λmax: chloroform) of the obtained dye was 448 nm. Reference Example 2 (Synthesis of dye of Example 2) The following structural formula 6.1 g of the compound represented by is dissolved in 15 ml of N,N-dimethylformamide, and then 3.8 g of tetracyanoethylene was gradually added and stirred at 40-50°C for 2 hours. After cooling, 100 ml of 90% methanol water was added to collect the precipitate. After washing with methanol and water, it was dried to obtain 5.2 g of dark red crystals. The obtained dye had a melting point of 162 to 168°C and a maximum absorption wavelength (λmax: chloroform) of 521 nm. Reference Example 3 (Synthesis of dye of Example 3) Sufficient nitrogen gas was blown into 90 ml of methanol, and the following structural formula was prepared. Add 30g of the compound represented by, cool to below 30℃, add 21.0g of hydroxyethylamine,
℃ for 2 hours, further reacted at 60℃ for 1 hour,
90 ml of NMP (N-methylpyrrolidone) was added, the mixture was cooled to room temperature, air was slowly removed, and the mixture was stirred at room temperature for 5 hours to carry out oxidation. Take the precipitated crystals,
23.0 g of dark blue crystals were obtained. The maximum absorption wavelength (λmax: chloroform) of the obtained dye was 650 nm. Example 1 (1) How to create a transfer sheet The above formula dye 2g Ethyl cellulose 8g Isopropanol 90g Total 100g A mixture of the above composition was mixed using glass beads.
The ink was prepared by mixing with a paint conditioner for about 30 minutes. Apply the above ink to a gravure proofing machine (plate depth 30μ)
A transfer sheet was prepared by coating a capacitor paper (thickness: 10 μm) using the same material as above and drying it naturally. (2) How to create a recording medium The above isocyanate compound 5g Polyester resin ^* 15g Methyl ethyl ketone 80g Total 100g *Manufactured by Toyobo Co., Ltd. "Vylon 200" (trade name) The above compositions were mixed to prepare a coating solution. Apply the above coating liquid to a gravure proofing machine (plate depth 30μ).
A recording medium was prepared by applying the mixture to high-quality paper and drying it naturally. (3) Transfer recording method The ink-applied side of the transfer sheet is overlapped with the coating solution-applied side of the recording medium, and a heat-sensitive recording head is used to heat the transfer sheet from the back side, producing a clear dark yellow record on the recording medium. was able to obtain. In order to test the stability of the recording obtained in this way, the recording surface was overlaid with high-quality paper at a density of 200 g/cm ²
Although the record was kept at 80°C for 24 hours under the pressure of Comparative Example 1 (1) Method for creating a transfer sheet A transfer sheet was created in the same manner as in Example 1. (2) Method for preparing a recording medium 15 g of polyester resin (Vylon 200) was dissolved in 85 g of methyl ethyl ketone to prepare a coating solution, and the coating solution was applied to high-quality paper in the same manner as in Example 1 to prepare a recording medium. (3) Transfer recording method The above transfer sheet and recording medium were superimposed and transfer recording was performed in the same manner as in Example 1 to obtain a dark yellow record. The records thus obtained were tested for stability in the same manner as in Example 1, and as a result, the stacked high-quality papers were significantly stained yellow due to migration of the dye from the recording material. Furthermore, the color density of the recording medium was significantly reduced due to the migration of the dye. Example 2 Substituting the dye and isocyanate used in Example 1 A dye represented by, and Transfer recording was carried out in the same manner as in Example 1 using the epoxy compound represented by , and as a result, a clear dark red recording was obtained. The stability of this record was tested in the same manner as in Example 1, and as a result, there was almost no change in the color of the record and almost no staining of the overlaid high-quality paper by the pigment. Comparative Example 2 Transfer recording and recording stability tests were conducted in the same manner using the dye used in Example 2 without using the epoxy compound shown in Example 2. As a result, a significant decrease in color density and overlapping were observed. Significant staining from the pigment on the combined paper was observed. Example 3 Substituting the color pigment and cysocyanate used in Example 1 A dye represented by, and Transfer recording was carried out in the same manner as in Example 1 using the blocked isocyanate shown in Figure 1. As a result, a clear dark blue recording was obtained. As a result of testing the stability of this record in the same manner as in Example 1,
There was almost no change in the color of the record and no staining of the superimposed high-quality paper by the dye. Comparative Example 3 Transfer recording and recording stability tests were conducted in the same manner using the dye shown in Example 3 without using the blocking isocyanate shown in Example 3. As a result, a significant decrease in color density and overlapping occurred. Significant staining of the high-quality paper with pigments was observed. Example 4 Instead of the dye shown in Example 2, reference examples 1 to
Transfer recording was carried out in the same manner as in Example 1 except for using a dye having the structural formula shown in Table 1 synthesized according to Example 3, and a recording with good stability could be obtained.

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Claims (1)

[Claims] 1 In a method of performing transfer recording by heating a transfer sheet coated with a dye with a thermal recording head to transfer the dye to a recording medium, the transfer sheet has active hydrogen atoms that react with epoxy groups or isocyanate groups. A dye is used, and a compound having an epoxy group, an isocyanate group, or a blocked isocyanate group is used in the recording medium, and the dye in the transfer sheet is used to bind to the epoxy group, isocyanate group, or blocked isocyanate group in the recording medium during transfer. A transfer recording method characterized by fixing a dye by reacting with a compound having a blocking isocyanate group.