JP5229624B2 - Thermal transfer sheet - Google Patents

Description

  The present invention relates to a thermal transfer sheet using a sublimation dye, and more particularly to a thermal transfer recording dye comprising a novel azomethine compound. More specifically, the invention can be manufactured at low cost and at low cost, and a magenta dye. The present invention relates to a novel dye for thermal transfer recording which is excellent in color tone when used as an ink.

  The heat-sensitive sublimation transfer method uses a thermal transfer film that supports a substrate with a dye layer in which a sublimable dye is dissolved or dispersed in a binder resin, and this thermal transfer film is superimposed on the image-receiving film to transfer image information to a heating device such as a thermal head. By applying energy according to the above, the sublimation dye contained in the dye layer on the thermal transfer film is transferred to the image receiving film to form an image.

This heat-sensitive sublimation transfer method can control the amount of dye transfer in dot units according to the amount of energy applied to the thermal transfer film, so that it is excellent in forming a gradation image and has advantages such as easy formation of characters, symbols, etc. have.
The image obtained by such a thermal transfer method can form a high-quality image similar to a silver salt photograph, and accordingly, there is an extremely high demand for prevention of image quality degradation due to factors such as light, heat, and humidity of the image. Development of various sublimation dyes for improving image storage stability has been made.

  In addition to the development of yellow, magenta, and cyan color dyes, various research and development have been conducted on combinations of these color dyes. For example, in Japanese Patent Application Laid-Open No. 2008-87309 (Patent Document 1), by combining a specific yellow dye coloring matter, magenta dye coloring matter, and cyan dye coloring matter, excellent fastness such as light resistance, and catalytic fading There has been proposed a thermal transfer sheet capable of obtaining a printed matter that is less likely to cause the occurrence of the problem.

JP 2008-87309 A

  The inventors of the present invention can suppress catalytic fading to some extent by combining a specific yellow dye, magenta dye, and cyan dye, and are light-fast in mixed colors, particularly the tertiary color black. The knowledge that can be improved. The present invention is based on this finding.

  Accordingly, an object of the present invention is to provide a thermal transfer sheet excellent in light fastness in mixed colors, particularly in black which is a tertiary color.

（式中、Ｒ_１はアルキル基、アリール基、水素、またはハロゲン原子を表し、Ｒ_２はカルボニルアミノ基またはカルボニルアルコキシ基を表す。）

（式中、Ｒ_３はアルキル基、アリール基、または水素を表し、Ｒ_４はアルキルオキシ基、アリールオキシ基、またはアミノ基を表す。）
前記マゼンタ染料は、下記式M-Iで表される染料色素を含んでなり、

（式中、
Ｒ_５は、フェニル基またはナフチル基であるが、該フェニル基またはナフチル基は、アルキル基もしくはハロゲンにより置換されていてもよく、
Ｒ_６およびＲ_７は、それぞれ独立して、炭素数Ｃ２〜４のアルキル基を示す。）
前記シアン染料は、下記式C-Iで表される染料色素を含んでなる、

（式中、Ｒ_８はアルキル基またはアリール基を表す。）、
ことを特徴とするものである。 The thermal transfer sheet according to the present invention is a thermal transfer sheet comprising at least a yellow dye layer, a magenta dye layer, and a cyan dye layer,
Each of the yellow dye layer, the magenta dye layer, and the cyan dye layer is provided with a dye layer comprising a dye pigment and a binder resin on a substrate.
The yellow dye comprises a dye pigment represented by the following formula YI and / or Y-II:

(In the formula, R ₁ represents an alkyl group, an aryl group, hydrogen, or a halogen atom, and R ₂ represents a carbonylamino group or a carbonylalkoxy group.)

(In the formula, R ₃ represents an alkyl group, an aryl group, or hydrogen, and R ₄ represents an alkyloxy group, an aryloxy group, or an amino group.)
The magenta dye comprises a dye pigment represented by the following formula MI,

(Where
R ₅ is a phenyl group or a naphthyl group, and the phenyl group or naphthyl group may be substituted with an alkyl group or a halogen,
R ₆ and R ₇ each independently represents an alkyl group having 2 to 4 carbon atoms. )
The cyan dye comprises a dye pigment represented by the following formula CI,

(Wherein R ₈ represents an alkyl group or an aryl group),
It is characterized by this.

  According to the present invention, by combining the specific yellow dye, magenta dye, and cyan dye described above, it is possible to suppress the catalytic fading to some extent, and the light fastness in the mixed color, particularly the tertiary color black. It is possible to realize a thermal transfer sheet that is excellent in the quality.

  The thermal transfer sheet according to the present invention is a thermal transfer sheet comprising at least a yellow dye layer, a magenta dye layer, and a cyan dye layer, wherein each of the yellow dye layer, the magenta dye layer, and the cyan dye layer is formed on a substrate. And a dye layer comprising a dye pigment and a binder resin. Hereinafter, each layer constituting the thermal transfer sheet will be described.

<Base material>
The base material constituting the thermal transfer sheet according to the present invention is for supporting a dye layer described later, and a known material can be used. Specifically, any one having a conventionally known heat resistance and strength may be used. For example, polyethylene terephthalate film, 1,4-polycyclohexylenedimethylene terephthalate film, polyethylene naphthalate film, polyphenylene Sulfide film, polystyrene film, polypropylene film, polysulfone film, aramid film, polycarbonate film, polyvinyl alcohol film, cellophane, cellulose derivatives such as cellulose acetate, polyethylene film, polyvinyl chloride film, nylon film, polyimide film, ionomer film, etc. Resin film; Papers such as condenser paper, paraffin paper, and synthetic paper; Nonwoven fabric; Composite of paper, nonwoven fabric and resin, and the like.

  The substrate generally has a thickness of about 0.5 to 50 μm, preferably about 3 to 10 μm.

  The substrate may be subjected to an adhesion treatment on one side or both sides as necessary. When the dye ink for forming the dye layer is applied on the base material, it is preferable to perform an adhesion treatment because the wettability and adhesiveness of the coating liquid are likely to be insufficient. Examples of the above-mentioned adhesion treatment include corona discharge treatment, flame treatment, ozone treatment, ultraviolet treatment, radiation treatment, surface roughening treatment, chemical treatment, plasma treatment, low temperature plasma treatment, primer treatment, grafting treatment, etc. The reforming technique can be applied as it is. Two or more of these treatments can be used in combination.

  Furthermore, it is also possible to apply and form an adhesive layer on the base material as the base material adhesion treatment. An adhesion layer can be formed from the following organic materials and inorganic materials, for example. Examples of the organic material include polyester resins, polyacrylate resins, polyvinyl acetate resins, polyurethane resins, styrene acrylate resins, polyacrylamide resins, polyamide resins, polyether resins, polystyrene resins, Examples thereof include polyethylene resins, polypropylene resins, polyvinyl chloride resins and polyvinyl alcohol resins, vinyl resins such as polyvinyl pyrrolidone and modified products thereof, and polyvinyl acetal resins such as polyvinyl acetoacetal and polyvinyl butyral. Examples of the inorganic material include silica (colloidal silica), alumina or alumina hydrate (alumina sol, colloidal alumina, cationic aluminum oxide or hydrate, suspicion bakumaite, etc.), aluminum silicate, magnesium silicate, magnesium carbonate, oxidation Examples include colloidal inorganic pigment ultrafine particles such as magnesium and titanium oxide.

  The primer treatment may be performed by applying a primer solution to an unstretched film and then stretching the plastic film when the plastic film is produced by stretching.

<Dye layer>
The thermal transfer sheet according to the present invention is obtained by forming at least a yellow dye layer, a magenta dye layer, and a cyan dye layer as a dye layer on a substrate. The transfer sheet may further form a conventionally known black dye layer as the dye layer.

  The thermal transfer sheet may be one in which each dye layer is formed in the surface order on the substrate. For example, a substrate sheet in which a plurality of dye layers such as yellow, magenta, cyan, and black are repeatedly provided in a surface sequence, a transfer protective layer is provided in a surface sequence in addition to the plurality of dye layers, and the like. Also good. In addition, you may provide black of a heat-meltable ink layer further.

（式中、Ｒ_１はアルキル基、アリール基、水素、またはハロゲン原子を表し、Ｒ_２はカルボニルアミノ基またはカルボニルアルコキシ基を表す。）

（式中、Ｒ_３はアルキル基、アリール基、または水素を表し、Ｒ_４はアルキルオキシ基、アリールオキシ基、またはアミノ基を表す。） <Yellow dye pigment>
The yellow dye layer comprises a yellow dye coloring matter represented by the following formulas YI and / or Y-II and a binder resin.

(In the formula, R ₁ represents an alkyl group, an aryl group, hydrogen, or a halogen atom, and R ₂ represents a carbonylamino group or a carbonylalkoxy group.)

(In the formula, R ₃ represents an alkyl group, an aryl group, or hydrogen, and R ₄ represents an alkyloxy group, an aryloxy group, or an amino group.)

In the above formula YI, R ₁ is preferably an alkyl group, more preferably an isopropyl group, and R ₂ is preferably a carbonyl group, more preferably a carbonylamino group, especially those represented by the following formula YII It is preferable that

In the above formula Y-II, R ₃ is preferably an aryl group, more preferably a phenyl group, and R ₄ is preferably an alkoxy group, and in particular, those represented by the following formula Y-II-I It is preferable that

  The yellow dye coloring matter represented by the formula Y-II-I can be produced by reacting a pyrazolone derivative and a benzylaldehyde derivative in the presence of a base. Moreover, you may manufacture according to the method as described in the patent 18991953.

In the present invention, it is preferable that the yellow dye pigment further comprises a dye pigment represented by the following formula Y-III and / or the following formula Y-IV. By using together the dye pigment represented by the formula YII or Y-II-I and the dye pigment represented by the following formula Y-III and / or the following formula Y-IV, it is brought close to the target hue as yellow Can do.

  The dye pigment represented by the above formula Y-III can be obtained as a commercial product, and examples thereof include Disperse Yellow 201 (Macrolex Yellow 6G, LANXESS). Moreover, the dye pigment | dye represented by the above-mentioned formula Y-IV can also be obtained as a commercial item, for example, Solvent Yellow 93 (For example, Plast Yellow 8000 (brand name), Arimoto Chemical Co., Ltd. product etc.) etc. Can be mentioned.

  In the present invention, as the yellow dye coloring matter, in addition to the above-described ones, dye coloring matters other than the above may be used together. For example, known aryl dyes such as diarylmethane dyes; triarylmethane dyes; thiazole dyes; merocyanine dyes; methine dyes such as pyrazolone methine; indoaniline dyes; acetophenone azomethine, pyrazoloazomethine, imidazole Azomethine dyes represented by azomethine, imidazoazomethine and pyridone azomethine; xanthene dyes; oxazine dyes; cyanostyrene dyes represented by dicyanostyrene and tricyanostyrene; thiazine dyes; azine dyes; acridine dyes; Benzeneazo dyes; azo colors other than the above general formula (I) such as pyridoneazo, thiophenazo, isothiazoleazo, pyrroleazo, pyralazo, imidazoleazo, thiadiazoleazo, triazoleazo, diazo ; Spiropyran dyes; Indian Linus Piropi run based dyes; fluoran dyes; rhodamine lactam-based dyes; naphthoquinone dyes; anthraquinone dyes; quinophthalone dyes, etc. may be used.

<Magenta dye pigment>
The magenta dye layer comprises a magenta dye coloring matter represented by the following formula MI and a binder resin.

In the above formula, R ₅ is a phenyl group or a naphthyl group, but the phenyl group or naphthyl group may be substituted with an alkyl group or a halogen, and R ₆ and R ₇ are each independently a carbon A C2-4 alkyl group is shown.

からなる群から選択されるものであることが好ましい。このような置換基を有していてもよいフェニル基またはナフチル基等のアリール基を導入することにより、所望の色相に近似させることができるとともに、吸収スペクトルがシャープ化する。また、耐光性や溶解性も向上する。これらのなかでも、吸収スペクトルのシャープ化、耐光性向上の観点から、Ｒ_１は、置換基(ii)および(iv)がより好ましい。 In the present invention, in the formula M-I, R ₅ represents the following substituents (i) to (v):

It is preferably selected from the group consisting of By introducing an aryl group such as a phenyl group or a naphthyl group which may have such a substituent, it is possible to approximate a desired hue and sharpen the absorption spectrum. Moreover, light resistance and solubility are also improved. Among these, R ₁ is more preferably substituents (ii) and (iv) from the viewpoint of sharpening the absorption spectrum and improving light resistance.

  The magenta dye dye of the above formula MI comprises a 1H-pyrazolo [1,5-b] [1,2,4] triazole coupler represented by the following formula II and a formula III as shown in the following synthesis scheme: Can be obtained by oxidative coupling reaction in the presence of a base.

  The 1H-pyrazolo [1,5-b] [1,2,4] triazole derivative represented by the formula II, which is a coupler, is synthesized using a method similar to the method described in JP-A-5-239367. be able to. For example, the compounds of formula II and formula III can be obtained as follows.

First, as shown in the following synthesis scheme, a benzoic acid ester compound as a starting material is reacted with acetonitrile in the presence of potassium t-butoxide to obtain compound a, and then compound a is reacted with hydrazine to obtain compound b. Prepare. Subsequently, imidate hydrochloride is allowed to act on compound b to obtain an amidine compound, and then hydroxylamine is allowed to act on compound b to obtain compound c.

Then, compound p is reacted with p-tolylsulfonic acid chloride as described below. The compound of formula II can be obtained by heating to reflux in the presence of pyridine.

  Moreover, the pyridyldiamine derivative which is a compound of Formula III can be obtained according to the method described in Japanese Patent No. 3078308, for example.

  The compound of the formula M-I can be obtained by reacting the compound of the formula II obtained as described above with the compound of the formula III with an oxidizing agent in the presence of a base. This reaction is performed, for example, within 40 ° C. under water cooling for about 1 hour.

In the present invention, the magenta dye pigment may further contain a dye pigment represented by the following formula M-II in addition to the above formula MI. By using these two types of magenta dye pigments together, the target hue can be brought closer, and the light resistance is further improved.

In the above formula, R ₉ represents a substituted or unsubstituted alkoxycarbonyl group, a substituted or unsubstituted amino group, a hydroxy group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted Represents an alkyl group, a substituted or unsubstituted cycloalkyl group, a heterocyclic group, or a halogen atom, R ₁₀ represents an amino group or a hydroxyl group, and n represents an integer of 2 or less, in which case R ₁₀ is the same as each other Or different.

In the present invention, R ₉ is preferably a hydroxyl group or an amino group, and R ₁₀ is preferably a phenoxy group. n is 1 or 2. The dye pigment of the formula M-II is particularly preferably of the following formula M-II-I and / or the formula M-II-II.

  Examples of the magenta dye coloring matter represented by the formula M-II-I include anthraquinone dyes such as Disperse Red 60, and examples of the magenta dye coloring matter represented by the formula M-II-II include Disperse Violet 26 and the like. And anthraquinone dyes.

<Cyan dye layer>
The cyan dye layer comprises a cyan dye coloring matter represented by the following formula CI and a binder resin.

In the above formula, R ₈ represents an alkyl group or an aryl group, more preferably a phenyl group, and particularly preferably one represented by the following formula CII.

  The cyan dye coloring matter represented by the above formula CI can be produced in the same manner as the indoaniline compound described in Japanese Patent No. 2572025, and the cyan dye coloring matter represented by the above formula CII is disclosed in Japanese Patent No. 5045436. It can be produced in the same manner as the indoaniline compound described in the publication.

  As the cyan dye coloring matter, other cyan dye coloring matter may be added in addition to the above. The other cyan dye pigment is not particularly limited as long as it is a dye that can be used for a conventionally known thermal transfer sheet and can be sublimated by heat. The solubility can be selected appropriately in consideration of the solubility and the like.

In the present invention, in addition to the cyan dyes of the above formula CI and the above formula CII, dye dyes represented by the following formulas C-II and / or C-III may be included.

  The cyan dye coloring matter represented by the above formula C-II can also be obtained as a commercial product, for example, Solvent Blue 63. Further, examples of the cyan dye pigment represented by the formula C-III include Disperse Blue 354 (Foron Brilliant Blue SR, Clariant Japan).

  As the cyan dye coloring matter, other cyan dye coloring matter may be added in addition to the above. The other cyan dye coloring matter is not particularly limited as long as it is a dye that can be used in a conventionally known thermal transfer sheet and can be sublimated by heat. To hue, printing sensitivity, light resistance, storage stability, binder The solubility can be selected appropriately in consideration of the solubility and the like.

  The content of various dyes depends on the combination of the base material and the primer, but the dye can obtain a sufficient density as an image (yellow, magenta, cyan reflection density 1.8 or more: when measuring ISO status A density). Content is preferred. The content range will be described later.

  Each of the dye layers contains a binder resin in addition to the specific dye. The binder resin is not particularly limited, and conventionally known ones can be used. For example, cellulose resins such as methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose acetate, cellulose butyrate; polyvinyl alcohol And vinyl resins such as polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl pyrrolidone, and polyacrylamide; polyester resins; phenoxy resins, and the like.

  The binder resin further includes a releasable graft copolymer. The releasable graft copolymer can be blended as a release agent. The releasable graft copolymer has at least one releasable segment selected from a polysiloxane segment, a fluorocarbon segment, a fluorinated hydrocarbon segment, and a long-chain alkyl segment as a polymer main chain constituting the binder resin. Is obtained by graft polymerization. As the releasable graft copolymer, a graft copolymer obtained by grafting a polysiloxane segment to a main chain composed of polyvinyl acetal is particularly preferable.

  Each dye layer may use additives such as a release agent, inorganic fine particles, and organic fine particles, if desired. Examples of the release agent include the above-described releasable graft copolymer, silicone oil, and phosphate ester. Inorganic fine particles include carbon black, aluminum, molybdenum disulfide and the like. Examples of the organic fine particles include polyethylene wax.

  Each dye layer is formed from a dye ink containing a specific dye, a binder resin, an additive to be added as required, and a solvent. The solvent is not particularly limited as long as it is a conventionally known dye ink material. For example, acetone, methanol, water, methyl ethyl ketone, toluene, ethanol, isopropyl alcohol, cyclohexanone, dimethylformamide [DMF], ethyl acetate, and the like. A mixed solvent of these solvents can be used, and among them, a mixed solvent of methyl ethyl ketone and toluene is preferable.

  In the dye ink containing a yellow dye coloring matter, the yellow dye coloring matter is preferably 50 to 300 parts by mass, and more preferably 85 to 250 parts by mass with respect to 100 parts by mass of the binder resin. Moreover, in yellow dye ink, it is preferable that content of a yellow dye pigment | dye is 0.5-15 mass%. Further, the yellow dye ink is preferably 2 to 30% by mass, more preferably 5 to 15% by mass, based on the total amount of the dye such as yellow dye pigment and the binder resin, that is, the solid content. . In addition, when yellow dye ink contains 2 or more types of dye pigment | dyes, all the content and solid content of the said yellow dye represent the total amount of each dye pigment | dye.

  In the dye ink containing a magenta dye pigment, the content of the magenta dye pigment is preferably 50 to 300 parts by mass, more preferably 85 to 250 parts by mass with respect to 100 parts by mass of the binder resin. When the magenta dye pigment contains two or more dye pigments, the content and solid content of the magenta dye pigment both represent the total amount of each dye pigment.

  In the dye ink containing a cyan dye coloring matter, the content of the cyan dye coloring matter is preferably 50 to 300 parts by mass, more preferably 85 to 250 parts by mass with respect to 100 parts by mass of the binder resin. In the cyan dye ink, the total amount of the cyan dye coloring matter and the binder resin, that is, the solid content is preferably about 2 to 30% by mass, and more preferably 5 to 15% by mass. In addition, when the said cyan dye pigment | dye contains 2 or more types of dye pigment | dyes, both content and solid content of the said cyan dye pigment | dye represent the total amount of each dye pigment | dye.

  Each dye ink is, for example, a paint shaker, a propeller-type stirrer, a dissolver, a homomixer, a ball mill, a bead mill, a sand mill, a two-roll mill, a three-roll mill, an ultrasonic disperser, a kneader, a line mixer, a twin-screw extruder, etc. It can prepare using a well-known manufacturing method.

  Each dye layer can be formed, for example, by coating each of the above-described dye inks on the substrate by a conventionally known method such as wire bar coating, gravure printing, reverse roll coating using a gravure plate, or the like. it can.

  As the coating method, gravure coating is preferred. Moreover, in coating, it is although it does not specifically limit, It is preferable to dry for about 1 second-about 5 minutes at the temperature of 60-120 degreeC. Insufficient drying of each dye ink causes the dye ink to turn over when it is soiled or wound, and then retransfers to the dye layer that has a different hue when the turned dye ink is turned over. So-called kickback may occur.

Each dye ink may be applied so that the dry coating amount is preferably about 0.2 to 3.0 g / m ² , more preferably about 0.4 to 1.0 g / m ² .

<Other layers>
In the thermal transfer sheet according to the present invention, a heat-resistant slipping layer may be formed on the base material surface opposite to the surface on which each dye layer is formed. The heat resistant slipping layer is provided to prevent problems caused by heat of the thermal head during thermal transfer, such as sticking and printing wrinkles.

  The heat resistant slipping layer is mainly composed of a heat resistant resin. The heat resistant resin is not particularly limited. For example, polyvinyl butyral resin, polyvinyl acetoacetal resin, polyester resin, vinyl chloride-vinyl acetate copolymer resin, polyether resin, polybutadiene resin, styrene-butadiene copolymer resin, Acrylic polyol, polyurethane acrylate, polyester acrylate, polyether acrylate, epoxy acrylate, urethane or epoxy prepolymer, nitrocellulose resin, cellulose nitrate resin, cellulose acetate propionate resin, cellulose acetate butyrate resin, cellulose acetate-hydrodiene Phthalate resin, cellulose acetate resin, aromatic polyamide resin, polyimide resin, polyamideimide resin, polycarbonate resin, chlorine Polyolefin resins.

  The heat resistant slipping layer may be formed by blending additives such as a slipperiness imparting agent, a crosslinking agent, a release agent, an organic powder, and an inorganic powder in addition to the above heat resistant resin.

In general, the heat-resistant slipping layer is prepared by adding the above-mentioned heat-resistant resin, and the above-described slipperiness-imparting agent and additives that are optionally added to the solvent, and dissolving or dispersing each component to thereby apply the heat-resistant slipping layer coating solution. Then, the heat resistant slipping layer coating solution can be coated on a substrate and dried.
As the solvent in the heat resistant slipping layer coating solution, the same solvent as that in the dye ink can be used.

Examples of the coating method of the heat resistant slipping layer coating liquid include wire bar coating, gravure printing, screen printing, reverse roll coating using a gravure plate, and gravure coating is particularly preferable. Heat-resistant slip layer coating solution, dry coating amount is preferably 0.1 to 3 g / ^{m 2,} more preferably may be applied so as to be 1.5 g / ^{m 2} or less.

  If the thermal transfer sheet of this invention has the above-mentioned dye layer on a base material, an undercoat layer etc. may be provided between the said base material and dye layer. The undercoat layer is not particularly limited, and a composition that improves the adhesion between the substrate and the dye layer can be appropriately selected and provided.

  The thermal transfer sheet according to the present invention may be one in which a transfer protective layer is further formed in the surface order with the above-mentioned dye layer so that a protective layer for protecting the image surface can be transferred after image formation. The configuration and preparation of the transfer protective layer are not particularly limited, and can be selected from conventionally known techniques depending on the characteristics of the base sheet, the dye layer, and the like to be used. In addition, when the base film is not releasable, the transfer protective layer is preferably provided with a release layer between the base film and the transfer protective layer to improve the transfer property of the transfer protective layer.

  The thermal transfer sheet according to the present invention heats and presses a predetermined portion with a thermal head or the like on the side opposite to the side on which the dye layer is provided of the base material, and transfers the dye in the portion corresponding to the printing portion of the dye layer to the transfer material Can be printed.

  A thermal transfer image receiving sheet or the like can be used as the transfer material. The thermal transfer image-receiving sheet is not particularly limited as long as the recording surface has dye acceptability. For example, a sheet having a dye-receiving layer formed on at least one surface of a substrate such as paper, metal, glass, or synthetic resin. Can be mentioned. The printer used when performing thermal transfer is not particularly limited, and a known thermal transfer printer can be used.

  The present invention will be described in more detail with reference to examples, but the present invention is not limited to the examples.

<Preparation of yellow ink>
According to the composition shown in Table 1 below, each component was mixed and stirred to prepare a yellow ink. In addition, a numerical value shows a weight part.

* Polyvinyl acetal resin (KS-5, 5% varnish, manufactured by Sekisui Chemical)
The yellow dyes of the formulas YII and Y-II-I in Table 1 have the following chemical structural formulas obtained according to the method described in Japanese Patent No. 5045436.

<Preparation of magenta ink>
In the same manner as above, according to the composition shown in Table 2 below, each component was mixed and stirred to prepare a magenta ink. In addition, a numerical value shows a weight part.

* Polyvinyl acetal resin (KS-5, 5% varnish, manufactured by Sekisui Chemical)
The chemical structural formula of each magenta dye in Table 2 is as follows.

The above formula MII was obtained as follows.
1500 ml of tetrahydrofuran was added to 442 ml of ethyl benzoate, 142 ml of acetonitrile was added at 0 ° C., and 304 g of potassium t-butoxide was added over 30 minutes. After stirring for about 1 hour, 900 ml of water was added and the mixture was separated with hexane, and the aqueous layer was neutralized to about pH 2 with concentrated hydrochloric acid. After neutralization, the mixture was separated with toluene, and the oil layer was distilled off under reduced pressure to obtain 407 g of Compound A as an acetonitrile derivative (yield 84%). Compound A was identified by HPLC and ESIMS. A synthesis scheme is shown below.

Next, 400 ml of 3-propanol was added to 405 g of Compound A and stirred at 40 ° C. To this, 136 g of hydrazine monohydrate was added dropwise and reacted at reflux temperature for 3 hours. Thereafter, about 300 ml of the reaction system was distilled off under reduced pressure, and 100 ml of saturated brine and 500 ml of toluene were added to separate the layers. After removing the aqueous layer, the oil layer was dried over magnesium sulfate. This toluene solution was distilled off under reduced pressure, and 450 ml of methanol was added to the residue. The methanol solution was added dropwise to 8000 ml of a saturated aqueous NaHCO ₃ solution to precipitate crystals. The crystals were collected by filtration and dried to obtain 368 g of Compound B, which is an aminopyrazole derivative (yield 84%). Compound B was identified by HPLC and ESIMS. A synthesis scheme is shown below.

Further, 367 g of Compound B was stirred in 1800 ml of methanol, and 208.2 g of imidate hydrochloride obtained from acetonitrile and methanol was added. After stirring at room temperature for 3 hours, 132.1 g of hydroxylamine hydrochloride and 36 g of caustic soda were added, and the mixture was stirred at 40 ° C. with heating. After reacting for 3 hours, the reaction system was transferred to 9000 ml to precipitate crystals. The crystals were collected by filtration and dried to obtain 378 g of compound C which is an amide oxime derivative (yield 79%). Compound C was identified by HPLC and ESIMS. A synthesis scheme is shown below.

Subsequently, 85 g of Compound C was stirred in 85 ml of DMAC and 85 ml of acetonitrile, 65 g of P-toluenesulfonic acid chloride was added under water cooling, and 27.4 ml of pyridine was added. After stirring for 30 minutes, 27.4 ml of pyridine and 280 ml of methanol were added and stirred while heating under reflux. After stirring for 5 hours, it was transferred to 1600 ml of water, and the crystals were collected by filtration. The crystals were recrystallized in 80 ml of methanol to obtain 52.2 g of Compound D (yield 66%). Compound D was identified by HPLC and ESIMS. A synthesis scheme is shown below.

Next, 1.4 g of Compound D was stirred in 9.8 ml of methanol, and 1.67 g of sodium hydroxide and 1.82 g of Compound E were added. Thereafter, an aqueous solution obtained by dissolving 3.57 g of sodium persulfate in 5.0 ml of water was added dropwise to the reaction solution. After stirring for 1 hour, the reaction solution was filtered, and the obtained residue was suspended in warm water at 40 ° C. for 1 hour. After filtering the suspension, the obtained solid was dissolved in toluene and purified by silica gel chromatography to obtain 1.17 g of the compound of formula MII (yield 48%). A synthesis scheme is shown below. The compound was identified by HPLC and ESIMS. The analysis results were as follows.
¹ H NMR, δ (ppm) (multiplicity, integral) (CDCl ₃ ) 9.29 (d, 1H), 7.46 (m, 4H), 6.67 (d, 1H), 3.66 (q, 4H), 2,59 (s, 3H), 2.43 (s, 3H), 1.26 (t, 6H)

Compounds of formula MI-II to MIV were prepared in the same manner as described above, but replacing the starting materials. A compound of formula MI-VI was prepared by using the following compound F in place of compound E in the preparation of the compound of formula MI-II.

The compound of formula MI-VII was prepared by using the following compound G in place of compound E in the preparation of the compound of formula MI-III.

As the comparative dye 1 in Table 2, a magenta dye represented by the following formula (D-9 dye described in Examples of Japanese Patent No. 3013137) was used.

In addition, as the comparative dye 2 in Table 2 above, a magenta dye (comparative dye A described in Japanese Patent No. 3013137) represented by the following formula was used.

<Preparation of cyan ink>
In the same manner as above, according to the composition shown in Table 3 below, each component was mixed and stirred to prepare a cyan ink. In addition, a numerical value shows a weight part.

* Polyvinyl acetal resin (KS-5, 5% varnish, manufactured by Sekisui Chemical)
In addition, the cyan dye of formula CII in Table 1 has the following chemical structural formula, and was produced according to the method described in Japanese Patent No. 5045436.

<Preparation of printed matter>
Each ink obtained as described above was applied onto a 4 μm-thick base material (4WF597, manufactured by Toray Industries, Inc.) using a bar coater so that the coating amount was 0.5 g / m ^2, and at 80 ° C. Dried for 2 minutes to produce yellow, magenta and cyan dye ribbons.

Next, 20 parts of vinyl chloride-vinyl acetate copolymer resin (Solvine C, manufactured by Nissin Chemical Industry), 2 parts of epoxy-modified silicone (X-22-3000T, manufactured by Shin-Etsu Chemical Co., Ltd.), toluene / methyl ethyl ketone (1 1 mixture) 78 parts of the composition obtained by mixing and stirring the film thickness after drying using a bar coater on a synthetic paper made of polypropylene (trade name: YUPO FPG150, manufactured by YUPO Corporation) having a thickness of 150 μm. Was coated and dried so as to be 5 μm, and further treated in an oven at 80 ° C. for 12 hours to obtain an image receiving paper.
Using the prepared dye ribbons of the respective colors, printing was performed on the image receiving paper by a thermal transfer printer (CP740, manufactured by Canon) to obtain a black printed matter having three colors.

<Evaluation of light resistance>
Using a xenon fade meter (CI4000, manufactured by Atlas), the printed matter was irradiated at 400 kJ (420 nm integrated value) for 24 hours. CIRA soda lime was used as a filter. For the printed matter before and after the light irradiation, the optical density was measured using a spectrocolorimeter (Spectrolino, manufactured by GretagMacbeth), and the density residual ratio was calculated by the following formula.
Concentration residual ratio = (optical density after irradiation) / (optical density before irradiation) × 100

The black printed matter obtained by combining each color of yellow, magenta, and cyan shown in Table 4 below has a minimum density remaining rate of 20% or more, and ○ is less than 20%. . The results were as shown in Table 4 below.

In Table 5, the black printed matter obtained by combining each color of yellow, magenta, and cyan has a minimum density remaining rate of 38% or more as ◯, and less than 38% as x. did. The results were as shown in Table 5 below.

Claims (8)

A thermal transfer sheet comprising at least a yellow dye layer, a magenta dye layer, and a cyan dye layer,
Each of the yellow dye layer, the magenta dye layer, and the cyan dye layer is provided with a dye layer comprising a dye pigment and a binder resin on a substrate.
The yellow dye comprises a dye pigment represented by the following formula YI and / or Y-II:

(In the formula, R ₁ represents an alkyl group, an aryl group, hydrogen, or a halogen atom, and R ₂ represents a carbonylamino group or a carbonylalkoxy group.)

(In the formula, R ₃ represents an alkyl group, an aryl group, or hydrogen, and R ₄ represents an alkyloxy group, an aryloxy group, or an amino group.)
The magenta dye comprises a dye pigment represented by the following formula MI,

(Where
R ₅ is a phenyl group or a naphthyl group, and the phenyl group or naphthyl group may be substituted with an alkyl group or a halogen,
R ₆ and R ₇ each independently represents an alkyl group having 2 to 4 carbon atoms. )
The cyan dye comprises a dye pigment represented by the following formula CI,

(Wherein R ₈ represents an alkyl group or an aryl group),
A thermal transfer sheet characterized by that. The thermal transfer according to claim 1, wherein the dye pigment of formula YI is represented by the following formula YII, and the dye pigment of formula Y-II is represented by the following formula Y-II-I. Sheet.

R _{5 in the} formula MI is the following substituents (i) to (v):

The thermal transfer sheet according to claim 1 or 2, which is selected from the group consisting of: The thermal transfer sheet according to any one of claims 1 to 3, wherein the dye pigment of the formula CI is represented by the following formula CII.

The thermal transfer sheet according to any one of claims 1 to 4, wherein the magenta dye and the cyan dye further comprise a dye pigment represented by the following formula M-II.

Wherein R ₉ is a substituted or unsubstituted alkoxycarbonyl group, a substituted or unsubstituted amino group, a hydroxy group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted an alkyl group, a substituted or unsubstituted cycloalkyl group, a heterocyclic group, or a halogen atom,, R ₁₀ represents a phenoxy radical, n is to table an integer of 2 or less, where, R ₁₀ is the same as each other It may or may not be.) The thermal transfer sheet according to claim 5, wherein the dye pigment of the formula M-II is the following formula M-II-I and / or the formula M-II-II.

The thermal transfer sheet according to any one of claims 1 to 6, wherein the yellow dye further comprises a dye pigment represented by the following formula Y-III and / or the following formula Y-IV.

The thermal transfer sheet according to any one of claims 1 to 7, wherein the cyan dye further comprises a dye pigment represented by the following formula C-II and / or C-III.