KR0119563B1 - Yellow mono-azo dye having pyridone structure for heat transfer print - Google Patents

Abstract

The invention provides a pyridone dye, yellow monoazo dye, for thermotransfer printing and a ink composition containing said dye. The yellow monoazo dye represented by general formula wherein R1 is H, unsubstituted alkyl of C1-C8, alkoxy or allyl-substituted alkyl of C1-C8, or unsubstituted, alkoxy or halogen-substituted allyl; X is H, alkyl of C1-C4, alcoxy or halogen; R2 is one of six substituents. The said ink composition is produced by dissolving 2-8% by weight of the said dye and 2-8% by weight of a binder in 84-96% by weight of a organic solvent.

Description

Pyridone Yellow Monoazo Dye for Thermal Transfer Recording

None.

[Industrial use]

The present invention relates to a pyridone monoazo dye for thermal transfer recording, and more particularly, to an imido-substituted pyridinated monoazo dye having excellent color and durability as a sublimation yellow dye used for thermal transfer recording.

[Prior art]

Recently, the thermal transfer recording method has been widely used in devices such as facsimile machines, copiers, and the like, and has been developed to print a color image electrically expressed from a color video camera or a computer through a color printer. As one method of reproducing such an image, a sublimation thermal transfer method has been proposed.

According to the thermal transfer method, first, an electric color image is 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. It 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 corresponding to one color, and the dye is transferred to the receiving layer from the selectively heated region, and the pattern is formed in a shape and concentration according to the pattern and intensity of heat applied to the transfer sheet. Will form. This assumption is repeated for the other two colors, and then a combination of the three pigments yields a color print corresponding to the original screen image.

The dye used in such a sublimation thermal transfer recording method must satisfy several conditions.

That is, these dyes must be (1) easily sublimed and pyrolyzed under the operating conditions of TPH, (2) have a high water absorption coefficient, (3) have stability against light, moisture, heat and chemicals, and (4) color It should have good color tone to reproduce and (5) be easy to synthesize.

As a filament used for thermal transfer, for example, US Patent No. 4,698,651 discloses a magenta dye having a substituted 5-arylazoisothiazole structure, and US Patent No. 4,701,439 discloses a cyanovinyltetra-hydroquinoline structure. A yellow dye having a polymer is disclosed. In the United States, in particular, US Pat. No. 4,695,287 discloses a cyan dye having the same structure as 2-carbamoyl-4- [N- (p-substituted noaryl) -imino] -1,4-naphthoquinone. It is starting.

US Pat. No. 4,764,178 also describes azo dyes having diazotizable heteroaromatic amines and aromatic coupling components. Japanese Laid-Open Patent Publication No. 59-78894 discloses a cyan dye having a naphthalene dione structure, and Japanese Laid-Open Patent Publication No. 59-227948 discloses a cyan dye having an anthraquinone structure. However, these various dyes do not meet all of the various requirements (characteristics of (1) to (5) above) for thermal transfer recording.

Therefore, these dyes are desired to improve stability to light and heat as well as to various color properties such as color tone, intermediate shade and color development.

In order to provide a yellow dye having improved properties as described above, US Patent No. 5,011,813 discloses a pyridone-based azo dye having the following structure:

Wherein R ¹ is aryl, C _1-4 unsubstituted or substituted (C _1-4 alkoxy, aryl) alkyl, and R ² is C _1-12 alkyl.

Similarly, EP 442,446 discloses pyridone-based azo dyes having the structure:

Wherein R is hydrogen, alkyl, cyclized alkyl, substituted or unsubstituted phenyl.

However, these two pyridone-based azo compound yellow dyes do not completely solve problems such as stability and color tone.

[Problem to solve the invention]

The present invention has been made to solve the problems of the prior art as described above, and an object of the present invention is to provide a dye for thermal transfer recording having high stability and excellent color tone.

[Means for solving the problem]

In order to achieve the above object of the present invention, the present invention provides a pyridone-based yellow mono azo dye for thermal transfer recording having the following structural formula (I).

Here, R ₁ is hydrogen, unsubstituted C _1-8 alkyl, alkoxy or aryl substituted C _1-8 alkyl, unsubstituted or alkoxy, halogen substituted aryl.

And X is hydrogen, C _1-4 alkyl, alkoxy, halogen, and R ₂ is selected from the following substituents.

Wherein R ₃ and R ₄ are each independently selected from the group consisting of hydrogen and a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, halogen, alkyl carboxylate, carbonyl, and R ₃ . R ₄ is not cyclized and R ₃ and R ₄ are each independently selected from the above substituents (R ₃ and R ₄ ), or represent a saturated or unsaturated cycloalkyl having 3 to 6 carbon atoms, and Z is nitro, halogen Or alkyl, alkoxy, sulfonyl, carbonyl, carboxyamide, sulfonamino, cyano, hydroxy or hydrogen having 1 to 4 carbon atoms.

An example of the compounds according to the present invention is as follows.

Among the compounds represented by the general formula (I) of the present invention, in the general formula (I), when R ₁ is alkyl having ₁ to 4 carbon atoms, X is a hydrogen atom, R ₂ is succinimido, maleimido, Phthalimido is particularly excellent in color development sensitivity compared to other compounds.

The dye of the present invention is dispersed and dissolved in a binder and an organic solvent to provide a thermal transfer ink composition, and applied onto a substrate to prepare a transfer sheet. The transfer sheet coated with the dye is brought into contact with the receiving sheet such that the dye is adjacent to the receiving sheet. Then, the backside of the transfer sheet is selectively heated and compressed with TPH to selectively transfer the dye to obtain the desired image recording on the receiving sheet.

The ink composition containing the dye compound of the present invention is preferably in the range of the dye 2 to 8% by weight of the formula (I) of the present invention, 2 to 8% by weight of the binder, the amount of the dye is 2 When the amount is less than the weight%, the concentration of the dye to be transferred is low and the color development sensitivity is lowered. On the other hand, when the amount is more than 8 weight%, problems of solubility and economy arise. The amount of binder is preferably in the range of 2 to 8% by weight. When the amount of the binder is less than 2% by weight, the viscosity of the composition is low and the adhesion is reduced, so that the dye may drop off during or after application.

On the other hand, if the amount is more than 8% by weight, the viscosity of the composition is so high that the coating process becomes difficult, the coating layer is not uniform, and the dye is difficult to transfer.

The binder used for the ink composition may be any resin material or polymer material suitable for bonding the dye to the substrate. Examples of suitable binders include cellulose derivatives such as ethylcellulose, hydroxyethylcellulose, methylcellulose, cellulose acetate butyrate, vinyl resins such as polyvinyl alcohol, polyvinylacetate, polyvinylbutyral, polyacrylamide and derivatives thereof; Polyacrylic acid, polymethylmethacrylate, polycarbonate, polysulfone, polyphenylene oxide and the like.

The organic solvent used in the ink composition may be methanol, ethanol, toluene, methyl ethyl ketone, cyclonucleic acid or N, N-dimethylformamide.

The ink composition may further include other additives such as hardeners, preservatives, and the like.

The ink composition is coated on a substrate to form a dye layer, preferably 0.4 to 2 mu m thick.

The transfer sheet substrate can withstand a high temperature of about 400 ° C. for a period of about 20 milliseconds, and is sufficient to transfer the heat applied on one side to the dye on the other side and transfer the dye to the receiving sheet within 10 milliseconds. Any conventional sheet material that can be thinned can be used.

Examples of suitable materials include polyesters such as polyethylene terephthalate, polyamides, polyacrylates, polycarbonates, cellulose esters, fluorine-based resins, polyacetals and polyamides, and the like.

The thickness of the base material is preferably in the range of 2 to 15 μm. If the thickness is thinner than 2 μm, the base film may be distorted when the high temperature is in contact with the TPH. On the other hand, if the thickness is thicker than 15 μm, the heat transfer may occur. Low thermal sensitivity.

A release layer may be applied to the back side of the receiving sheet substrate to prevent the substrate film from distorting and the TPH from adhering to the film. Materials for such release layers include carboxylates, sulfonates, phosphates, aliphatic amines, polyoxyethylene alkyl esters, polyethylene glycol fatty acid esters, silicone oils or synthetic oils.

It is preferable that a dye barrier layer is formed between the base film and the dye layer to prevent the dye from being thermally transferred to the substrate. The material for the dye barrier layer may be a hydrophilic polymer such as polyacrylamide, butyl methacrylate, polyvinyl alcohol or polyvinylacetate.

The receiving sheet usually includes a substrate having a dye receiving layer thereon. The receiving sheet base material may be polyethylene terephthalate, polyester sulfone, polyamide, cellulose ester, polyester coated with white pigment, synthetic paper, or the like.

The dye receiving layer is applied on the substrate to better absorb and diffuse the transferred dye.

The dye receiving layer can be, for example, polycarbonate, polyurethane, polyester, polyamide, polyvinyl chloride, styrene-acrylonitrile copolymer or polycaprolactam.

The dye receiving layer preferably comprises a release material such as wax or silicone oil to facilitate separation of the layer after dye transfer.

EXAMPLE

The invention will be described in more detail by the following examples.

However, the following examples are merely illustrative and exemplary of the present invention and should not be construed to limit the present invention to the specific examples.

Example 1

A) Synthesis of Compound Y ₁

4-phthalimadoaniline (4-phthalimidoaniline, 1 mmol) was dissolved in 0.2 ml of concentrated hydrochloric acid, and the temperature was lowered to 0 ° C.

An aqueous solution of sodium nitrite (1 mmol) was slowly added dropwise to the solution at 0 ° C. The following pyridone compound (1) (1 mmol) was dissolved in 3 ml of water, and the resulting solution was slowly added dropwise at 0 ° C, followed by stirring for 30 minutes.

The yellow precipitated product was filtered off, washed several times with water, and vacuum-rolled to obtain pure Y ₁ (0.8 mmol, 80%).

B) preparation of ink composition

4% by weight of the above-mentioned a) Compound Y ₁ Compound Y ₁ and 4% by weight of BX-5 polybutylral resin prepared in the synthesis process were dispersed and dissolved in 96% by weight of methyl ethyl ketone at 50 ° C, followed by cooling To prepare an ink composition.

C) Manufacture of transfer sheet

The ink composition prepared above was applied to a polyethylene terephthalenite film sheet having a thickness of 7 μm using a bar coater so as to have a dry coating amount of 1 g / m 2, and then dried to prepare a transfer sheet.

Example 2-8

Instead of the compound Y ₁ of Example 1) described above, using the compound shown in the following (Table 1) was carried out in substantially the same manner as in Example 1) to prepare a transfer sheet.

Comparative Example 1

Instead of the compound Y ₁ of Example 1) described above using a compound A of the following structural formula, the transfer sheet was prepared in substantially the same manner as in Example 1).

Comparative Example 2

Instead of the compound Y ₁ of Example 1) described above using a compound B of the following structural formula, the transfer sheet was prepared in the same manner as in Example 1).

The color development and stability of each exhibition sheet prepared in Examples 1 to 8 and Comparative Examples 1 and 2 were evaluated by the following method, and the results are shown in Table 1 below.

1) Evaluation of Color Development

In the thermosensitive recording device (TH-FMR) set to 22 V of TPH and 1.5 watts / dot of power, the color development was evaluated using a transfer sheet and an accommodating sheet (Sony, UPC 3010) manufactured in each of Examples or Comparative Examples. It was.

The color density was measured using a densitometer (TR 1224).

2) Evaluation of dye stability

The receiving sheet having the dye transfer phase formed from the transfer sheets prepared in Examples and Comparative Examples was subjected to 48 hours under conditions of 35 ± 2 ° C. and 60 ± 2 ° C. RH using xenon and wedometer (Atlas, ES-25). Left for a while. The decrease in concentration during this period was measured with a densitometer.

Example 1

Example 2

Example 3

Example 4

Example 5

Example 6

Example 7

Example 8

Comparative Example 1

Comparative Example 2

As shown in Table 1, the dyes of the structural formula (I) of the present invention all have a good or acceptable color tone, and have excellent dye stability as compared to the control dye having a similar structure when used as a thermal transfer ink. I can see that.

Claims (7)

Pyridone-based yellow mono azo dye for thermal transfer recording having the following structural formula (I): Wherein R ₁ is selected from the group consisting of hydrogen, unsubstituted C _1-8 alkyl, alkoxy or aryl substituted C _1-8 alkyl, unsubstituted or alkoxy, halogen substituted aryl; X is Hydrogen, C _1-4 alkyl, alkoxy, halogen; And R ₂ is independently selected from the group consisting of the following substituents. Wherein R ₃ and R ₄ are each independently selected from the group consisting of hydrogen and a substituted or unsubstituted C _1-4 alkyl group, halogen, alkyl carboxylate, carbonyl, and R ₃ … R ₄ is R ₃ and R ₄ are not cyclized and are each independently selected from the above substituents (R ₃ and R ₄ ) or represent C _3-6 saturated or unsaturated cycloalkyl; Z is nitro, halogen, C _1-8 alkyl, alkoxy, sulfonyl, carbonyl, capboxamide, sulfonamino, cyano, hydroxy or hydrogen.) The dye according to claim 1, wherein R ₁ is selected from hydrogen, unsubstituted C _1-8 alkyl, unsubstituted phenyl, benzyl. 2. The dye of claim 1 wherein X is selected from the group consisting of hydrogen, halogen in the ortho position and alkyl in the alkoxy and meta position. The dye according to claim 1, wherein R ₂ is selected from the group consisting of succinimido, maleimido, phthalimido and in each case an imido group to which a substituent is attached. The compound according to claim 1 or 4, wherein R ₃ and R ₄ are independently alkyl having 1-2 carbon atoms and R ₃ . Dye having a saturated or unsaturated ring having 4-5 carbon atoms when R ₄ . The dye according to claim 1 or 5, wherein Z is selected from the group consisting of acetamido, nitro and halogen hydrogen atoms. 2 to 8% by weight of the pyridone-based yellow monoazo dye for thermal transfer recording according to claim 1; 2 to 8% by weight of a binder capable of adhering the above dye on a substrate; 84 to 96% by weight of an organic solvent in which the dye and the binder are dissolved; An ink composition comprising.