KR0180885B1 - Indoaniline dye, ink composition containing it and transfer sheet - Google Patents

Abstract

The present invention relates to an indoaniline-based dye, an ink composition containing the same, and a transfer sheet, which are excellent in color and durability, and are represented by the following structural formula (I), which is useful for thermal transfer recording.

Wherein R ¹ , R ² , R ⁵ and Q are as defined in the detailed description of the invention, respectively.

Description

Indoaniline dyes, ink compositions and transfer sheets containing the same

The present invention relates to an indoaniline-based dye, an ink composition and a transfer sheet containing the same, which are excellent in color and durability and useful for thermal transfer recording.

In recent years, the thermal transfer recording method has been widely used not only for facsimile machines and copiers but also for printing color images electrically expressed from color video cameras or computers through color printers. As one method of reproducing such an image, a sublimation thermal transfer method has been proposed.

According to the thermal transfer method, an electric color image is first separated by a filter, and each separated color image is an electrical signal of Y (Yellow: yellow), M (Magenta: magenta), and C (Cyan: cyan). Is generated and sent to the thermal transfer printer. A transfer sheet in which thermally transferable yellow, magenta, and cyan dyes are applied to a sheet-like substrate in the form of an ink is a thermal printing head (TPH) in contact with a material to be transferred, that is, a receiving sheet. Is inserted between and the flat roller. TPH has many heating elements and is heated continuously in response to yellow, magenta and cyan signals. The transfer sheet is selectively heated in accordance with a pattern information signal substituted for one color, and the dye is transferred from the selectively heated region to the receiving layer to form a pattern according to the shape and concentration according to the pattern and intensity of heat applied to the transfer sheet. To form. This process is repeated for the other main color, and then a combination of the three pigments produces a color print corresponding to the original screen image.

The dye used in such a sublimation thermal transfer recording method must satisfy several conditions as follows. That is, the thermal transfer dye should be (1) easily sublimated and pyrolyzed under the operating conditions of TPH, (2) have a high molar absorption coefficient, and (3) have stability against light, moisture, heat and chemicals. (4) have good color tones for color reproduction, and (5) easy to synthesize.

As a dye for thermal transfer recording that satisfies such characteristics, US Pat. No. 4,695,287 discloses an indo aniline-based cyan dye represented by the following structural formula (A).

Wherein R ^a , R ^b and R ^e are C ₁ to C ₆ alkyl groups or C ₅ to C ₇ cyclized alkyl groups and R ^c and R ^d are hydrogen, halogen, -NHCOR ^a , -NHSO ₂ R ^a And C ₁ to C ₆ alkyl groups.

In addition, EP 209,991 discloses an anthraquinone cyan dye represented by the following structural formula (B).

Wherein R is C ₁ ~ C ₆ alkyl group, C ₄ ~ C ₈ cycloalkyl group or C ₂ ~ C ₆ alkenyl group and R ^a is C ₁ ~ C ₆ alkyl group or C ₂ ~ C ₆ alkenyl ego; R ^b is an alkenyl group of a hydrogen atom, C ₂ ~ C ₆ alkyl group or a C ₂ ~ C ₆ a.

However, the conventional dyes do not fully satisfy the basic requirements as dyes for thermal transfer recording such as stability and color tone, and improvements in color development characteristics and stability have been required.

Therefore, the inventors of the present invention have been researched to produce a new thermal transfer dye that can solve the problems of the conventional thermal transfer dye as described above, the present invention by preparing the inaniline-based cyan dye represented by the structural formula (I) The invention has been completed.

Hereinafter, the present invention will be described in detail.

The present invention is characterized by an indoaniline cyan dye for thermal transfer recording represented by the following structural formula (I).

Wherein R ¹ and R ² are the same or different and are each selected from a hydrogen atom, a C ₁ to C ₆ alkyl group, a phenyl group and a benzyl group; R ⁵ is one selected from among Al kokgi a hydrogen atom, a halogen atom, C ₁ ~ C ₆ alkyl group and C ₁ ~ C ₆ of; Q is selected from the following substituents , or And wherein, R ³ and R ⁴ is each selected from the same or different and represents hydrogen atom, an alkoxy group of the alkyl group and a C ₁ ~ C ₂ of the C ₁ ~ C _2.

In the indo aniline dyes according to the present invention, R ¹ and R ² are each a methyl group or an ethyl group, R ⁵ is a hydrogen atom or a methyl group, and Q is or It is especially excellent in color development and durability.

In addition, particularly preferred cyan dyes among the indoaniline-based cyan dye represented by the structural formula (I) are as follows.

The cyan dye represented by the structural formula (I) according to the present invention is dispersed and dissolved in an organic solvent with a binder to prepare a thermal transfer ink composition, and coated on a substrate to prepare a transfer stool. The cyan dye-coated transfer sheet of the present invention is brought into contact with the accommodating sheet such that the cyan dye is adjacent to the accommodating sheet, and then the backside of the transfer seat is selectively heated and compressed with TPH to selectively transfer the dye to the desired accommodating sheet. Image recording is obtained.

The present invention also includes an ink composition containing cyan dye represented by the above formula (I) as a main component.

The ink composition of the present invention contains 2 to 8% by weight of the cyan dye represented by the formula (I), 2 to 8% by weight of the binder, and 84 to 96% by weight of the organic solvent. In the ink composition of the present invention, when the cyan dye represented by the above formula (I) is contained less than 2% by weight, the concentration of the transferred dye is low and the color sensitivity is lowered, whereas when it is contained in an amount exceeding 8% by weight, it is soluble. And economics. If the content of the binder is less than 2% by weight, the viscosity of the composition is low so that the adhesiveness is reduced, and there is a fear that the dye may drop off when applied or after application. On the other hand, if the content of the binder exceeds 8% by weight, the viscosity of the composition is too high, so that the coating process Not only is it difficult and the coating layer becomes uneven, but also the dye is difficult to transfer. The binders used in the present invention are suitable resins or polymers suitable for bonding dyes to substrates, for example, cellulose derivatives such as ethylcellulose, hydroxyethyl cellulose, methyl cellulose, cellulose acetate butyrate; Vinyl resins and derivatives thereof such as polyvinyl alcohol, polyvinylacetate, polyvinyl butyral and polyacrylamide; Polyacrylic acid, polymethyl methacrylate, polycarbonate, polysulfone, polyphenylene oxide and the like can be used. The organic solvent used in the ink composition may be, for example, methanol, ethanol, toluene, methyl ethyl ketone, cyclohexane or N, N-dimethylformamide. In addition, the ink composition may be used by adding other additives such as hardening agents and preservatives.

The present invention also includes a transfer sheet having the ink composition coated on a substrate.

The transfer sheet of the present invention is coated with an ink composition on a substrate to form a dye layer preferably 0.4 ~ 2.0㎛ thickness. The substrate used to manufacture the transfer sheet can withstand a period of about 20 milliseconds at a high temperature of about 400 ° C., and transfers the heat applied on one side to the dye on the other side to transfer the dye to the receiving sheet within 10 milliseconds. Any sheet material that can be thin enough to be used can be used. Substrate materials that can be used in the present invention are, for example, polyesters such as polyethylene terephthalate, polyamides, polyacrylates, polycarbonates, cellulose esters, fluororesins, polyacetals and the like. It is preferable that the substrate has a thickness of 2 to 15 µm. If the thickness is thinner than 2 µm, the substrate film may be distorted upon contact with a high temperature TPH. On the other hand, if the thickness is thicker than 15 µm, the heat transfer may be low. Sensitivity is reduced.

In addition, a release layer may be applied to the back side of the receiving sheet substrate to prevent the base film from being distorted or adhered to the film. As the material of the release layer, for example, carboxylate, sulfonate, phosphate, aliphatic amine, polyoxyethylene alkyl ester, polyethylene glycol fatty acid ester, silicone oil, synthetic oil and the like can be used.

In addition, it is preferable to form a dye barrier layer between the base film and the dye layer to prevent the dye from being thermally transferred to the substrate. As the material for the dye barrier layer, for example, polyacrylamide, butyl methacrylate, polyvinyl Hydrophilic polymers such as alcohols, polyvinylacetates can be used.

The receiving sheet usually comprises a substrate having a dye receiving layer thereon. As the base for the receiving sheet, polyethylene terephthalate, polyester sulfone, polyamide, cellulose ester, polyester coated with white pigment, synthetic paper and the like can be used.

The dye receiving layer may be applied to the dye receiving layer on the substrate to better absorb and diffuse the transferred dye. Examples of the dye receiving layer include polycarbonate, polyurethane, polyester, polyamide, polyvinyl chloride, and styrene-acryl. Nitrile copolymers, polycarrolactams can be used. The dye receiving layer preferably includes a release material such as wax or silicone oil to facilitate separation of the layer after dye transfer.

Such a present invention will be described in more detail based on the following examples, but the present invention is not limited to the following examples.

Example 1 Preparation of Compound No. 1

The compound (1 mol) represented by the following structural formula (A) and the compound (1 mol) represented by the following structural formula (B) are added to a mixed solution of water (2 ml) and ethyl acetate (3 ml), and anhydrous K is added thereto. ₂ CO ₃ (4 mol) was added and stirred at room temperature. While stirring the reaction solution, a K ₃ Fe (CN) ₆ (6 mol) solution dissolved in water (3 mL) was slowly added dropwise at room temperature for 30 minutes using a dropping funnel. After the addition was completed, the reaction solution was kept stirring for 30 minutes. The reaction solution was separated into layers and the organic layer was taken. The organic layer was washed with water and brine sequentially and distilled under reduced pressure. The residue was recrystallized from ethanol to obtain the pure target compound (yield 60%).

[Examples 2 to 8]: Preparation of Compound Nos. 2 to 8

Different target materials were used to prepare the respective target compounds shown in the following table by the same preparation method as in Example 1.

Experimental Example

-Ink composition manufacturing-

4 wt% of the compound of the present invention prepared in Examples 1 to 8, the compound shown in U.S. Patent No. 4,695,287 (Comparative Example 1), and the compound shown in European Patent No. 209,991 (Comparative Example 2), and An ink composition was prepared by dispersing and dissolving 4% by weight of BX-1 polybutyral resin (manufactured by Integra Chemicals Co., Ltd.) in methyl ethyl ketone at 50 ° C, followed by cooling.

-Manufacture of Transfer Sheet-

Each ink composition prepared above was applied to a 7 占 퐉 -thick polyethylene terephthalate film sheet using a bar coder to apply a dry coating amount of 1 g / m 2 and then dried to prepare a transfer sheet.

Each transfer sheet prepared above was evaluated for color development and dye stability in the following manner, the results are shown in the following table.

(1) Evaluation of Color Development

The color development was evaluated using the transfer sheet and accommodating sheet (SONY, UPC 3010) prepared above in a thermosensitive recording device (TH-FMR) set at an applied voltage of 22V and a power of 1.5 watts / dot of TPH. The color density was measured using a densitometer (TR 1224).

(2) Evaluation of Dye Stability

A receiving sheet having a dye transfer image formed from each transfer sheet prepared above was left to stand for 48 hours at 35 ± 2 ° C. and 60 ± 2% RH using a xenon wedometer (Atlas, ES-25). . The decrease in concentration during this period was measured with a densitometer.

As shown in the following table, the transfer sheet to which the ink composition containing the cyan dye represented by the structural formula (I) according to the present invention is coated has a good color development or a color tone of more than an acceptable value (coloring concentration: 1.9). It can be seen that also shows excellent dye stability.

Claims (5)

Indoaniline cyan dye represented by the following structural formula (I). Wherein R ¹ and R ² are the same or different and are each selected from a hydrogen atom, an alkyl group of C ₁ to C ₆ , a phenyl group and a benzyl group; R ⁵ being one selected from a hydrogen atom, a halogen atom, C ₁ ~ alkyl group and a C ₁ ~ C ₂ Al kokgi of the C _2; Q is selected from the following substituents In this case, R ³ and R ⁴ is each selected from the same or different and represents hydrogen atom, an alkoxy group of the alkyl group and a C ₁ ~ C ₂ of the C ₁ ~ C _2. The indoaniline-based cyan dye according to claim 1, wherein R ¹ and R ² are each selected from a methyl group and an ethyl group. The indoaniline-based cyan dye according to claim 1, wherein R ⁵ is a methyl group. An ink composition comprising 2 to 8% by weight of indoaniline-based cyan dye represented by Structural Formula (I), 2 to 8% by weight of binder, and 84 to 96% by weight of organic solvent. Transfer sheet, characterized in that the ink composition of claim 4 is coated on the substrate.