JP2005119280A - Heat transfer recording material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat transfer recording material which can obtain a sufficient photographic printing density corresponding to growing high of photographic printing speed of heat transfer and making higher of characteristics required to a media an effective active degree (transfer property) of a dye is high and a photographic printing matter of high quality can be obtained. <P>SOLUTION: The heat recording material is composed of a heat transfer sheet having a dye layer on at least one side surface of a base material sheet and a heat transfer image receiving on at least one side surface of the base material sheet. After the dye layer and the receptive layer are piled up, in a heat transfer recording material the dye in the layer can be transferred by a heating means, the dye layer contains the dye and a binder resin and at least one kind of a melting point (MP<SB>1</SB>) of the dye is at most 130°C to be features in the heat transfer recording material. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a novel thermal transfer recording material, and more particularly to a thermal transfer recording material comprising a thermal transfer sheet of a thermal sublimation transfer system and a thermal transfer image receiving sheet.

  Conventionally, as a color or monochrome image forming technique, a thermal transfer sheet containing a thermal diffusible dye having a property of diffusing and transferring by heating is opposed to an image receiving layer of the image receiving sheet, and a thermal printing means such as a thermal head or a laser. A technique for forming an image by transferring the heat diffusible dye to the image receiving layer in an image-like manner is known. Such a thermal transfer system is well-established as a method that enables image formation with digital data, does not use a processing solution such as a developer, and can form a high image quality comparable to a silver salt photograph.

  In recent years, heat-sensitive transfer materials and image forming methods (post-chelates) using heat-diffusible dyes that can be chelated (hereinafter referred to as chelate dyes) for the purpose of improving the stability of the obtained images, particularly fixing and light resistance. For example, Japanese Patent Laid-Open Nos. 59-78893, 59-109349, and 60-2398.

  However, with the recent increase in printing speed of thermal transfer printers, there has been a problem that conventional thermal transfer recording materials cannot provide a sufficient print density or have insufficient transferability. In addition, until now, despite the large amount of dye remaining on the thermal transfer sheet after printing, the thermal transfer sheet that has been used once has been discarded, resulting in high running costs and a major drawback. Is hindering.

  In the post-chelation technique, the image-receiving layer contains a metal ion-containing compound that is not used in the normal dye thermal transfer recording system. In order to complete the process, it may be necessary to increase the applied energy or increase the amount of the metal ion-containing compound. In particular, increasing the amount of the metal ion-containing compound is a problem in terms of material cost. .

  As a method for improving the problem of the print density, a method of improving the print density by improving the state of the dye in the thermal transfer sheet is disclosed (for example, see Patent Document 1). However, in this method, no mention is made regarding problems associated with dye remaining.

  Also, a method for improving transferability by making certain phthalates exist in the dye-receiving layer of the thermal transfer image-receiving sheet is disclosed (for example, see Patent Document 2). In the present situation where higher speeds are expected, it is difficult to say that the effect is sufficient.

As described above, adjustments on the thermal transfer printer side and thermal transfer recording materials consisting of the thermal transfer sheet and thermal transfer image receiving sheet have been made in response to higher thermal printing speeds and higher media requirements. However, the two problems of print density and transferability have not been satisfied at the same time.
JP 2003-220768 A Japanese Patent Publication No. 6-65511

  The present invention has been made in view of the above-described problems, and its purpose is to achieve a sufficient printing density in response to an increase in the printing speed of thermal transfer and an advance in the required characteristics of the media, and the effectiveness of the dye. It is to provide a thermal transfer recording material that has a high degree of utilization (transferability) and can obtain a high-quality printed matter.

The above object of the present invention is achieved by the following configurations.
(Claim 1)
Consists of a thermal transfer sheet having a dye layer on at least one side of the base sheet and a thermal transfer image receiving sheet having a dye receiving layer on at least one side of the base sheet, and the dye layer and the receiving layer are overlaid Thereafter, in the thermal transfer recording material capable of transferring the dye in the dye layer to the dye receiving layer by a heating means, the dye layer contains a dye and a binder resin, and at least one melting point (MP A thermal transfer recording material characterized in that ₁ ) is 130 ° C. or lower.
(Claim 2)
2. The thermal transfer recording material according to claim 1, wherein at least one melting point (MP ₁ ) of the dye is 70 ° C. or less.
(Claim 3)
A thermal transfer sheet having a dye layer on at least one side of the base sheet and a thermal transfer image receiving sheet having a dye receiving layer on at least one side of the base sheet, the dye layer and the dye receiving layer being stacked In the thermal transfer recording material in which the dye in the dye layer can be transferred to the dye receiving layer by heating means after combining, the dye layer contains a dye and a binder resin, and at least one melting point (MP ₁ ) is 130 ° C. or lower, and the difference (Tg ₁ −MP ₁ ) between the glass transition temperature (Tg ₁ ) of the main binder constituting the binder resin and the melting point (MP ₁ ) of the dye is 0 ° C. or higher. A thermal transfer recording material characterized by being.
(Claim 4)
The difference (Tg ₁ -MP ₁ ) between the glass transition temperature (Tg ₁ ) of the main binder constituting the binder resin and the melting point (MP ₁ ) of the dye is 15 ° C. or more. The thermal transfer recording material described.
(Claim 5)
The difference (Tg ₁ -MP ₁ ) between the glass transition temperature (Tg ₁ ) of the main binder constituting the binder resin and the melting point (MP ₁ ) of the dye is 30 ° C. or more. The thermal transfer recording material described.
(Claim 6)
The thermal transfer recording material according to claim 3, wherein at least one melting point (MP ₁ ) of the dye is 70 ° C. or less.
(Claim 7)
The thermal transfer recording material according to claim 3, wherein the heat of fusion of at least one of the dyes is 110 J / g or less.
(Claim 8)
At least one melting point (MP ₁ ) of the dye contained in the dye layer of the thermal transfer sheet and the glass transition temperature (Tg ₂ ) of the main binder constituting the binder resin contained in the dye receiving layer of the thermal transfer image-receiving sheet The thermal transfer recording material according to claim 3, wherein the difference (MP ₁ −Tg ₂ ) is −60 degrees to 60 degrees.
(Claim 9)
The melting point (MP ₁ ) of at least one dye contained in the dye layer of the thermal transfer sheet and the glass transition temperature (Tg ₂ ) of the main binder constituting the binder resin contained in the dye receiving layer of the thermal transfer image-receiving sheet The thermal transfer recording material according to claim 3, wherein the difference (MP ₁ −Tg ₂ ) is −30 degrees to 30 degrees.
(Claim 10)
The thermal transfer recording material according to claim 1, wherein the dye-receiving layer contains a metal ion-containing compound capable of reacting with a dye to form a chelate compound.
(Claim 11)
The thermal transfer recording material according to claim 10, wherein the dye is a dye capable of forming a chelate by reacting with a metal ion-containing compound.

  According to the present invention, a sufficient printing density can be obtained in response to an increase in the printing speed of thermal transfer and an increase in the required characteristics of the media, and the effective use (transferability) of the dye is high, so that high quality is achieved. It is possible to provide a thermal transfer recording material from which a printed matter can be obtained.

  Hereinafter, the best mode for carrying out the present invention will be described in detail, but the present invention is not limited thereto.

As a result of intensive studies in view of the above problems, the present inventor has a thermal transfer sheet having a dye layer, a dye receiving layer, the dye layer containing a dye and a binder resin, and at least one kind of the dye A thermal transfer recording material having a melting point (MP ₁ ) of 130 ° C. or lower, or a dye layer containing a dye and a binder resin, wherein at least one melting point (MP ₁ ) of the dye is 130 ° C. or lower, and the binder The thermal transfer recording material in which the difference (Tg ₁ -MP ₁ ) between the glass transition temperature (Tg ₁ ) of the main binder constituting the resin and the melting point (MP ₁ ) of the dye is 0 ° C. or higher enables high thermal transfer printing speed. A thermal transfer recording material that can obtain a high-quality printed matter with sufficient printing density and high effective dye utilization (transferability) can be achieved in response to increasing demands on media and media. What you can do Heading, is up which led to the present invention.

  Details of the present invention will be described below.

  The thermal transfer recording material of the present invention comprises a thermal transfer sheet having a dye layer on at least one side of a base sheet, and a thermal transfer image receiving sheet having a dye receiving layer on at least one side of the base sheet.

  FIG. 1 is a cross-sectional view showing an example of the configuration of a thermal transfer sheet and a thermal transfer image receiving sheet constituting the thermal transfer recording material of the present invention.

  FIG. 1 a is a cross-sectional view showing a typical configuration of a thermal transfer sheet according to the present invention. The thermal transfer sheet 1 has a dye layer 3 on one surface of a base sheet 2, and the base sheet 2 The other surface is provided with a heat resistant slipping layer 4. FIG. 1 b) is a cross-sectional view showing a typical configuration of the thermal transfer image receiving sheet according to the present invention. The thermal transfer image receiving sheet 11 has a dye receiving layer 13 on one surface of a base sheet 12. ing.

<Thermal transfer sheet>
First, the thermal transfer sheet according to the present invention will be described.

(Substrate sheet)
As the base sheet used in the thermal transfer sheet according to the present invention, conventionally known materials can be used as the base sheet of the thermal transfer sheet. Specific examples of preferred substrate sheets are thin papers such as glassine paper, condenser paper, paraffin paper, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyphenylene sulfide, polyether ketone, polyether sulfone and other high heat resistant polyesters. Polypropylene, fluororesin, polycarbonate, cellulose acetate, polyethylene derivatives, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, polyimide, polymethylpentene, ionomer, etc. The thing which was done is mentioned. The thickness of the base sheet can be appropriately selected depending on the material so that the strength, heat resistance and the like are appropriate, but usually a thickness of about 1 to 100 μm is preferably used.

  Moreover, when adhesion with the dye layer formed on the surface of the substrate sheet is poor, it is preferable to perform primer treatment or corona treatment on the surface.

(Dye layer, dye)
The dye layer constituting the thermal transfer sheet according to the present invention is a heat sublimable color material layer containing at least a dye and a binder resin. The dye used for the heat sublimable colorant layer can be basically used as long as it has a melting point of 130 ° C. or lower, and preferably 70 ° C. or lower. Further, the heat of fusion of at least one dye is preferably 110 J / g or less.

  The dyes used in the dye layer according to the present invention may be used alone or in combination of two or more. In the case of using a plurality of kinds of dyes, the gist of the present invention is that at least one dye satisfying the above conditions is used in the dye layer. .

  By using such a dye, the transferability of the dye can be improved, the amount of the dye remaining in the dye layer can be reduced, and a higher printing density can be obtained.

  Below, the dye which can be used by this invention is demonstrated.

  As the dye according to the present invention, various conventionally known dyes for thermal transfer recording materials can be used without limitation as long as they have a melting point of 130 ° C. or lower, and among them, a heat-diffusible dye capable of forming a chelate is used. It is preferable to use it.

  The heat-diffusible dye capable of forming a chelate is not particularly limited as long as thermal transfer is possible, and various known compounds can be appropriately selected and used. For example, JP-A-59-78893, Cyan dyes, magenta dyes, yellow dyes and the like described in JP-A-59-109349, JP-A-4-94974, JP-A-4-97894, and Japanese Patent No. 2856225 can be used.

  For example, examples of the chelate cyan dye include compounds represented by the following general formula (1).

In the general formula (1), R ₁₁ and R ₁₂ each represents a substituted or unsubstituted aliphatic group, and R ₁₁ and R 12 may be the same or different. Examples of the aliphatic group include an alkyl group, a cycloalkyl group, an alkenyl group, and an alkynyl group. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and an i-propyl group. Examples of a group that can replace these alkyl groups include a linear or branched alkyl group (for example, a methyl group). Group, ethyl group, i-propyl group, t-butyl group, n-dodecyl group, 1-hexylnonyl group, etc.), cycloalkyl group (for example, cyclopropyl group, cyclohexyl group, bicyclo [2.2.1]) Heptyl group, adamantyl group and the like), alkenyl group (for example, 2-propylene group, oleyl group, etc.), aryl group (for example, phenyl group, ortho-tolyl group, ortho-anisyl group, 1-naphthyl group, 9- Anthranyl group, etc.), heterocyclic group (for example, 2-tetrahydrofuryl group, 2-thiophenyl group, 4-imidazolyl group, 2-pyridyl group, etc.) Halogen atom (eg, fluorine atom, chlorine atom, bromine atom), cyano group, nitro group, hydroxy group, carbonyl group (eg, alkylcarbonyl group such as acetyl group, trifluoroacetyl group, pivaloyl group, benzoyl group, pentane) Fluorobenzoyl group, arylcarbonyl group such as 3,5-di-t-butyl-4-hydroxybenzoyl group), oxycarbonyl group (for example, methoxycarbonyl group, cyclohexyloxycarbonyl group, n-dodecyloxycarbonyl group, etc.) Aryloxycarbonyl groups such as alkoxycarbonyl group, phenoxycarbonyl group, 2,4-di-t-amylphenoxycarbonyl group, 1-naphthyloxycarbonyl group, 2-pyridyloxycarbonyl group, 1-phenylpyrazolyl-5-oxy Carbonyl Heterocyclic oxycarbonyl groups, etc.), carbamoyl groups (for example, dimethylcarbamoyl groups, 4- (2,4-di-t-amylphenoxy) butylaminocarbonyl groups and other alkylcarbamoyl groups, phenylcarbamoyl groups, 1-naphthyl Arylcarbamoyl group such as carbamoyl group), alkoxy group (for example, methoxy group, 2-ethoxyethoxy group, etc.), aryloxy group (for example, phenoxy group, 2,4-di-t-amylphenoxy group, 4- (4 -Hydroxyphenylsulfonyl) phenoxy group), heterocyclic oxy group (for example, 4-pyridyloxy group, 2-hexahydropyranyloxy group, etc.), carbonyloxy group (for example, acetyloxy group, trifluoroacetyloxy group, Alkylcarbonyloxy groups such as pivaloyloxy group, Zoyloxy group, aryloxy group such as pentafluorobenzoyloxy group), urethane group (for example, alkylurethane group such as N, N-dimethylurethane group, N-phenylurethane group, N- (p-cyanophenyl) urethane group Aryl urethane groups, etc.), sulfonyloxy groups (for example, methanesulfonyloxy groups, trifluoromethanesulfonyloxy groups, alkylsulfonyloxy groups such as n-dodecanesulfonyloxy groups, benzenesulfonyloxy groups, p-toluenesulfonyloxy groups, etc.) An arylsulfonyl group such as a dimethylamino group, a cyclohexylamino group, an alkylamino group such as an n-dodecylamino group, an anilino group, an arylamino group such as a pt-octylanilino group, etc.) , Sulfonylamino group ( For example, methanesulfonylamino group, heptafluoropropanesulfonylamino group, alkylsulfonylamino group such as n-hexadecylsulfonylamino group, p-toluenesulfonylamino group, arylsulfonylamino group such as pentafluorobenzenesulfonylamino), Famoylamino group (for example, alkylsulfamoylamino group such as N, N-dimethylsulfamoylamino group, arylsulfamoylamino group such as N-phenylsulfamoylamino group), acylamino group (for example, Alkylcarbonylamino group such as acetylamino group, myristoylamino group, arylcarbonylamino group such as benzoylamino group, etc., ureido group (for example, alkylureido group such as N, N-dimethylaminoureido group, N-phenylurea, etc.) Group, arylureido groups such as N- (p-cyanophenyl) ureido group), sulfonyl groups (eg, alkylsulfonyl groups such as methanesulfonyl group and trifluoromethanesulfonyl group, arylsulfonyl groups such as p-toluenesulfonyl group) ), Sulfamoyl groups (for example, dimethylsulfamoyl groups, alkylsulfamoyl groups such as 4- (2,4-di-t-amylphenoxy) butylaminosulfonyl group, arylsulfamo groups such as phenylsulfamoyl group) Moyl group etc.), alkylthio group (eg methylthio group, t-octylthio group etc.), arylthio group (eg phenylthio group etc.), heterocyclic thio group (eg 1-phenyltetrazole-5-thio group, 5-methyl) -1,3,4-oxadiazol-2-thio group and the like.

  Examples of the cycloalkyl group and the alkenyl group are the same as the above substituents. Examples of the alkynyl group include 1-propyne, 2-butyne, 1-hexyne and the like.

As R ₁₁ and R ₁₂ , a group that forms a non-aromatic cyclic structure (eg, pyrrolidine ring, piperidine ring, morpholine ring, etc.) is also preferable.

R ₁₃ is preferably an alkyl group, a cycloalkyl group, an alkoxy group, or an acylamino group among the above substituents. n represents an integer of 0 to 4, and when n is 2 or more, the plurality of R ₁₃ may be the same or different.

R ₁₄ is an alkyl group, and examples thereof include a methyl group, an ethyl group, an i-propyl group, a t-butyl group, an n-dodecyl group, and a 1-hexylnonyl group. R ₁₄ is preferably a secondary or tertiary alkyl group, and examples of a preferable secondary or tertiary alkyl group include an isopropyl group, a sec-butyl group, a tert-butyl group, and a 3-heptyl group. The most preferred substituent for R ₁₄ is an isopropyl group or a tert-butyl group. The alkyl group of R ₁₄ may be substituted, but is all substituted with a substituent consisting of a carbon atom and a hydrogen atom. They are not substituted with substituents containing other atoms.

R ₁₅ is an alkyl group, and examples thereof include an n-propyl group, i-propyl group, t-butyl group, n-dodecyl group, 1-hexylnonyl group and the like. R ₁₅ is preferably a secondary or tertiary alkyl group, and preferred examples of the secondary or tertiary alkyl group include an isopropyl group, a sec-butyl group, a tert-butyl group, and a 3-heptyl group. The most preferred substituent for R ₁₅ is an isopropyl group or a tert-butyl group. The alkyl group for R ₁₅ may be substituted, but is all substituted with a substituent consisting of a carbon atom and a hydrogen atom. They are not substituted with substituents containing other atoms.

R ₁₆ represents an alkyl group, and examples thereof include n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, isopropyl group, sec-butyl group, tert-butyl group. , 3-heptyl group and the like. Particularly preferred substituents for R ₁₆ are straight-chain alkyl groups having 3 or more carbon atoms, such as n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl. And most preferably an n-propyl group or an n-butyl group. The alkyl group represented by R ₁₆ may be substituted, but is all substituted with a substituent consisting of a carbon atom and a hydrogen atom, and is not substituted with a substituent containing other atoms.

  Moreover, as a chelate yellow pigment | dye, the compound represented by following General formula (2) can be mentioned.

In the general formula (2), examples of each substituent represented by R ₁ and R ₂ include a halogen atom, an alkyl group (an alkyl group having 1 to 12 carbon atoms, an oxygen atom, a nitrogen atom, a sulfur atom). Alternatively, a substituent linked by a carbonyl group may be substituted, or an aryl group, alkenyl group, alkynyl group, hydroxyl group, amino group, nitro group, carboxyl group, cyano group or halogen atom may be substituted. Methyl, isopropyl, t-butyl, trifluoromethyl, methoxymethyl, 2-methanesulfonylethyl, 2-methanesulfonamidoethyl, cyclohexyl, etc.), aryl groups (for example, phenyl, 4-t-butylphenyl, 3 -Groups such as nitrophenyl, 3-acylaminophenyl, 2-methoxyphenyl), cyano group, a Lucoxyl group, aryloxy group, acylamino group, anilino group, ureido group, sulfamoylamino group, alkylthio group, arylthio group, alkoxycarbonylamino group, sulfonamido group, carbamoyl group, sulfamoyl group, sulfonyl group, alkoxycarbonyl group, Examples include a heterocyclic oxy group, an acyloxy group, a carbamoyloxy group, a silyloxy group, an aryloxycarbonylamino group, an imide group, a heterocyclic thio group, a phosphonyl group, and an acyl group.

Examples of the alkyl group and aryl group represented by R ₃ include the same alkyl groups and aryl groups represented by R ₁ and R ₂ .

Specific examples of the 5- to 6-membered aromatic ring constituted with two carbon atoms represented by Z ₁ include benzene, pyridine, pyrimidine, triazine, pyrazine, pyridazine, pyrrole, furan, thiophene and pyrazole. , Imidazole, triazole, oxazole, thiazole and the like, and these rings may further form a condensed ring with other aromatic rings. These rings may have a substituent, and examples of the substituent include the same substituents represented by R ₁ and R ₂ .

  Moreover, as a chelate magenta pigment | dye, the compound represented by following General formula (3) can be mentioned.

In the general formula (3), X represents at least a bidentate chelate-forming group or group of atoms, and Y represents a group of atoms forming a 5-membered or 6-membered aromatic hydrocarbon ring or heterocycle. , R ¹ and R ² each represent a hydrogen atom, a halogen atom or a monovalent substituent. n represents 0, 1, 2;

  X is particularly preferably a group represented by the following general formula (4).

In the general formula (4), Z ₂ represents an atomic group necessary for forming an aromatic nitrogen-containing heterocyclic ring substituted with at least one group containing a chelatable nitrogen atom. Specific examples of the ring include pyridine, pyrimidine, thiazole, imidazole and the like. These rings may further form a condensed ring with another carbocycle (such as a benzene ring) or a heterocycle (such as a pyridine ring).

  In the general formula (3), Y represents a group of atoms forming a 5-membered or 6-membered aromatic hydrocarbon ring or heterocyclic ring, and the ring may further have a substituent, and is condensed. You may have a ring. Specific examples of the ring include 3H-pyrrole ring, oxazole ring, imidazole ring, thiazole ring, 3H-pyrrolidine ring, oxazolidine ring, imidazolidine ring, thiazolidine ring, 3H-indole ring, benzoxazole ring, benzimidazole ring, A benzothiazole ring, a quinoline ring, a pyridine ring, etc. are mentioned. These rings may form a condensed ring with another carbocyclic ring (for example, benzene ring) or a heterocyclic ring (for example, pyridine ring). Examples of substituents on the ring include alkyl groups, aryl groups, heterocyclic groups, acyl groups, amino groups, nitro groups, cyano groups, acylamino groups, alkoxy groups, hydroxy groups, alkoxycarbonyl groups, halogen atoms, etc. The group may be further substituted.

R ¹ and R ² each represent a hydrogen atom, a halogen atom (for example, a fluorine atom, a chlorine atom) or a monovalent substituent, and examples of the monovalent substituent include an alkyl group, an alkoxy group, a cyano group, Examples thereof include an alkoxycarbonyl group, an aryl group, a heterocyclic group, a carbamoyl group, a hydroxy group, an acyl group, and an acylamino group.

  X represents at least a bidentate chelating group or a group of atoms, and may be any compound capable of forming a dye as the general formula (3), for example, 5-pyrazolone, imidazole, pyrazolopyrrole, pyrazolopyrazole, pyra Zoloimidazole, pyrazolotriazole, pyrazolotetrazole, barbituric acid, thiobarbituric acid, rhodanine, hydantoin, thiohydantoin, oxazolone, isoxazolone, indandione, pyrazolidinedione, oxazolidinedione, hydroxypyridone, or pyrazolopyridone are preferred .

(Binder resin)
The dye layer according to the present invention contains a binder resin together with the dye.

  As the binder resin used in the dye layer, a binder resin used in a heat transfer sheet of a conventionally known thermal sublimation transfer method can be used. For example, cellulose-based, polyacrylic acid-based, polyvinyl alcohol-based, polyvinyl pyrrolidone-based And water-soluble polymers such as acrylic resin, methacrylic resin, polystyrene, polycarbonate, polysulfone, polyethersulfone, polyvinyl butyral, polyvinyl acetal, ethyl cellulose, and nitrocellulose. Among these resins, polyvinyl butyral, polyvinyl acetal or cellulose resin having excellent storage stability is preferable.

  The contents of the dye and the binder resin in the dye layer are not particularly limited, and are preferably set as appropriate from the viewpoint of performance.

In the present invention, as a binder resin, one of the characteristics is that a binder having a glass transition temperature (Tg ₁ ) at which the difference from the melting point (MP ₁ ) of the dye is 0 ° C. or more is used.

The difference (Tg ₁ -MP ₁ ) between the glass transition temperature (Tg ₁ ) of the main binder constituting the binder resin and the melting point (MP ₁ ) of the dye is 0 ° C. or more, preferably 15 ° C. It is above, More preferably, it is 30 degreeC or more, More preferably, it is 30-200 degreeC.

  Regarding the value of the glass transition temperature of the binder resin according to the present invention, see J.A. Brandrup. E. H. Immersut, “Polymer Handbook” 3rd edition (John Wily & Sons, 1989) VI / 209 to VI / 277, from which binder resins having a desired Tg value are appropriately selected and used. be able to. Further, the glass transition temperature of the binder resin according to the present invention can be determined by a differential scanning calorimetry (DSC).

  Further, the dye layer according to the present invention may contain various known additives as required in addition to the above-described dye and binder resin. The dye layer is prepared by, for example, applying an ink coating solution prepared by dissolving or dispersing the above-mentioned dye, binder resin, or other additive in an appropriate solvent on a base sheet by a known means such as a gravure coating method. Then, it can be formed by drying. The thickness of the dye layer according to the present invention can be about 0.1 to 3.0 μm, preferably about 0.3 to 1.5 μm.

(Protective layer)
The thermal transfer sheet according to the present invention preferably includes a thermal transfer protective layer. The heat transferable protective layer comprises a transparent resin layer serving as a protective layer covering the surface of an image formed by thermal transfer on an image receiving sheet.

  Examples of the resin forming the protective layer include polyester resins, polystyrene resins, acrylic resins, polyurethane resins, acrylic urethane resins, polycarbonate resins, epoxy-modified resins of these resins, resins obtained by modifying these resins with silicone, and the like. Examples thereof include a mixture of these resins, an ionizing radiation curable resin, and an ultraviolet blocking resin. Preferred resins include polyester resins, polycarbonate resins, epoxy-modified resins, and ionizing radiation curable resins. As the polyester resin, an alicyclic polyester resin in which the diol component and the acid component have one or more alicyclic compounds is preferable. As the polycarbonate resin, an aromatic polycarbonate resin is preferable, and an aromatic polycarbonate resin described in JP-A No. 11-151867 is particularly preferable.

  Examples of the epoxy-modified resin used in the present invention include epoxy-modified urethane, epoxy-modified polyethylene, epoxy-modified polyethylene terephthalate, epoxy-modified polyphenyl sulfite, epoxy-modified cellulose, epoxy-modified polypropylene, epoxy-modified polyvinyl chloride, epoxy-modified polycarbonate, Epoxy modified acrylic, epoxy modified polystyrene, epoxy modified polymethyl methacrylate, epoxy modified silicone, copolymer of epoxy modified polystyrene and epoxy modified polymethyl methacrylate, copolymer of epoxy modified acrylic and epoxy modified polystyrene, epoxy modified acrylic and epoxy modified Examples include silicone copolymers, preferably epoxy-modified acrylic, epoxy-modified polystyrene, and epoxy-modified polymers. Methacrylate and epoxy-modified silicone, more preferably a copolymer of epoxy-modified polystyrene and epoxy-modified polymethyl methacrylate, a copolymer of epoxy-modified acrylic and epoxy-modified polystyrene, and a copolymer of epoxy-modified acrylic and epoxy-modified silicone. .

<Ionizing radiation curable resin>
An ionizing radiation curable resin can be used as the heat transferable protective layer. By containing it in the thermal transferable protective layer, the plasticizer resistance and scratch resistance are particularly excellent. As the ionizing radiation curable resin, known ones can be used. For example, a radically polymerizable polymer or oligomer is crosslinked and cured by irradiation with ionizing radiation, and a photopolymerization initiator is added if necessary, and an electron beam is added. Those obtained by polymerization and crosslinking with ultraviolet rays can be used.

<UV blocking resin>
The main purpose of the protective layer containing the ultraviolet blocking resin is to impart light resistance to the printed material. As the ultraviolet blocking resin, for example, a resin obtained by reacting and bonding a reactive ultraviolet absorber to a thermoplastic resin or the above ionizing radiation curable resin can be used. More specifically, a conventionally known non-reactive organic ultraviolet absorber such as salicylate, benzophenone, benzotriazole, substituted acrylonitrile, nickel chelate or hindered amine is added to an addition polymerizable double bond ( Examples thereof include those in which a reactive group such as a vinyl group, an acryloyl group, a methacryloyl group), an alcoholic hydroxyl group, an amino group, a carboxyl group, an epoxy group, or an isocyanate group is introduced.

  The main protective layer provided in the heat transferable protective layer having a single layer structure or the heat transferable protective layer having a multilayer structure as described above is usually about 0.5 to 10 μm, although it depends on the kind of the resin for forming the protective layer. Form to thickness.

  The thermal transferable protective layer of the present invention is preferably provided on the base sheet via a non-transferable release layer.

  The non-transferable release layer always makes the adhesive force between the base sheet and the non-transferable release layer sufficiently higher than the adhesive force between the non-transferable release layer and the heat transferable protective layer, In addition, for the purpose of increasing the adhesive force between the non-transferable release layer and the heat transferable protective layer before application of heat to that after application of heat, (1) together with the resin binder, average particles 30 to 80% by mass of inorganic fine particles having a diameter of 40 nm or less, or (2) an alkyl vinyl ether / maleic anhydride copolymer, a derivative thereof, or a mixture thereof in a ratio of 20% by mass or more in total. Or (3) it preferably contains an ionomer in a proportion of 20% by mass or more. The non-transferable release layer may contain other additives as necessary.

  Examples of the inorganic fine particles include silica fine particles such as anhydrous silica and colloidal silica, and metal oxides such as tin oxide, zinc oxide, and zinc antimonate. The particle diameter of the inorganic fine particles is preferably 40 nm or less. If the thickness exceeds 40 nm, the unevenness of the surface of the heat transferable protective layer increases due to the unevenness of the surface of the release layer, and as a result, the transparency of the protective layer is lowered, which is not preferable.

  The resin binder to be mixed with the inorganic fine particles is not particularly limited, and any resin that can be mixed can be used. For example, polyvinyl alcohol resins (PVA) of various saponification degrees; polyvinyl acetal resins; polyvinyl butyral resins; acrylic resins; polyamide resins; cellulose resins such as cellulose acetate, alkyl cellulose, carboxymethyl cellulose, hydroxyalkyl cellulose; Examples thereof include resins.

  The blending ratio (inorganic particulate / other blending components) of the inorganic particulates and other blending components mainly composed of a resin binder is preferably in the range of 30/70 or more and 80/20 or less in terms of mass ratio. When the blending ratio is less than 30/70, the effect of the inorganic fine particles becomes insufficient. On the other hand, when the blending ratio exceeds 80/20, the release layer does not become a complete film, and the base sheet and the protective layer are in direct contact with each other. End up.

  Examples of the alkyl vinyl ether / maleic anhydride copolymer or derivatives thereof include those in which the alkyl group of the alkyl vinyl ether portion is a methyl group or an ethyl group, and the maleic anhydride portion is partially or completely alcohol (for example, methanol, ethanol, etc.). , Propanol, isopropanol, butanol, isobutanol and the like) can be used.

  The release layer may be formed only with an alkyl vinyl ether / maleic anhydride copolymer, a derivative thereof, or a mixture thereof, but for the purpose of adjusting the peeling force between the release layer and the protective layer, A resin or fine particles may be further added. In that case, the release layer preferably contains 20% by mass or more of an alkyl vinyl ether / maleic anhydride copolymer, a derivative thereof, or a mixture thereof. When the content is less than 20% by mass, the effect of the alkyl vinyl ether / maleic anhydride copolymer or its derivative cannot be sufficiently obtained.

  The resin or fine particles blended in the alkyl vinyl ether / maleic anhydride copolymer or its derivative is not particularly limited as long as it can be mixed and can provide high film transparency at the time of film formation, and any material can be used. I can do it. For example, the above-mentioned inorganic fine particles and resin binders that can be mixed with the inorganic fine particles are preferably used.

  As the ionomer, for example, Surlyn A (manufactured by DuPont), Chemipearl S series (manufactured by Mitsui Petrochemical Co., Ltd.) or the like can be used. Further, for example, the above-mentioned inorganic fine particles, a resin binder that can be mixed with the inorganic fine particles, or other resins and fine particles can be further added to the ionomer.

  In order to form a non-transferable release layer, a coating solution containing any of the above components (1) to (3) in a predetermined blending ratio is prepared, and the coating solution is subjected to a gravure coating method or gravure reverse. It apply | coats on a base material sheet | seat by well-known techniques like a coating method, and dries an application layer. The thickness of the non-transferable release layer is usually about 0.1 to 2 μm after drying.

  The thermal transferable protective layer laminated on the base sheet with or without the non-transferable release layer may have a multilayer structure or a single layer structure. In the case of a multi-layer structure, in addition to the main protective layer, which is the main component for imparting various durability to the image, thermal transfer protection is provided to enhance the adhesion between the heat transfer protective layer and the image receiving surface of the print. An adhesive layer disposed on the outermost surface of the layer, an auxiliary protective layer, and a layer for adding a function other than the original function of the protective layer (for example, an anti-counterfeit layer, a hologram layer, etc.) may be provided. The order of the main protective layer and the other layers is arbitrary, but usually other layers are arranged between the adhesive layer and the main protective layer so that the main protective layer becomes the outermost surface of the image receiving surface after transfer. .

  An adhesive layer may be formed on the outermost surface of the heat transferable protective layer. The adhesive layer may be formed of a resin having good adhesiveness when heated, such as acrylic resin, vinyl chloride resin, vinyl acetate resin, vinyl chloride / vinyl acetate copolymer resin, polyester resin, and polyamide resin. it can. In addition to the above resin, the above-mentioned ionizing radiation curable resin, ultraviolet blocking resin and the like may be mixed as necessary. The thickness of the adhesive layer is usually 0.1 to 5 μm.

  In order to form a thermal transferable protective layer on a non-transferable release layer or a substrate sheet, for example, a protective layer coating solution containing a protective layer forming resin, an adhesive layer coating containing a thermal adhesive resin A coating liquid for forming a liquid and other layers to be added as necessary is prepared in advance, and these are applied in a predetermined order on a non-transferable release layer or a substrate sheet and dried. Each coating solution may be applied by a conventionally known method. Moreover, you may provide an appropriate primer layer between each layer.

<UV absorber>
It is preferable that at least one layer of the heat transferable protective layer contains an ultraviolet absorber, but when it is contained in the transparent resin layer, the transparent resin layer is present on the outermost surface of the printed matter after transfer of the protective layer. The heat sensitive adhesive layer is particularly preferred because the effect is reduced over time due to the influence of the environment over a long period of time.

  Examples of the ultraviolet absorber include salicylic acid-based, benzophenone-based, benzotriazole-based, and cyanoacrylate-based ultraviolet absorbers. Specific examples thereof include Tinuvin P, Tinuvin 234, Tinuvin 320, Tinuvin 326, Tinuvin 327, and Tinuvin 328. Tinuvin 312, Tinuvin 315 (Ciba Geigy), Sumisorb-110, Sumisorb-130, Sumsorb-140, Sumisorb-200, Sumsorb-250, Sumisorb-300, Sumisorb-320, Sumisorb-340, 350 Sumisorb-400 (above, manufactured by Sumitomo Chemical Co., Ltd.), Mark LA-32, Mar LA-36, Mark 1413 (or more, Adeka Argus Chemical Co., Ltd.) can be obtained from the market under the trade name, etc., both can be used in the present invention.

  Further, a random copolymer having a Tg of 60 ° C. or higher, preferably 80 ° C. or higher, in which a reactive ultraviolet absorber and an acrylic monomer are randomly copolymerized may be used.

  The above-mentioned reactive ultraviolet absorbers are conventionally known salicylates, benzophenones, benzotriazoles, substituted acrylonitriles, nickel chelates, hindered amines and other non-reactive ultraviolet absorbers such as vinyl groups and acryloyl groups, Addition-polymerizable double bonds such as methacryloyl groups, or those having introduced an alcoholic hydroxyl group, amino group, carboxyl group, epoxy group, isocyanate group or the like can be used. Specifically, UVA635L, UVA633L (above, manufactured by BASF Japan Ltd.), PUVA-30M (manufactured by Otsuka Chemical Co., Ltd.) and the like can be obtained from the market, and any of them can be used in the present invention. .

  The amount of the reactive ultraviolet absorbent in the random copolymer of the reactive ultraviolet absorbent and the acrylic monomer as described above is in the range of 10 to 90 mass%, preferably 30 to 70 mass%. Moreover, the molecular weight of such a random copolymer can be about 5000-250,000, Preferably it can be about 9000-30000. The above-mentioned ultraviolet absorber and the random copolymer of the reactive ultraviolet absorber and the acrylic monomer may be contained alone or in combination. The addition amount of the random copolymer of the reactive ultraviolet absorber and the acrylic monomer is preferably 5 to 50% by mass with respect to the layer to be contained.

  Of course, other light-proofing agents may be included in addition to the ultraviolet absorber. Here, the light-proofing agent is an agent that prevents or alters the degradation or decomposition of the dye by absorbing or blocking the action of degrading or decomposing the dye, such as light energy, thermal energy, and oxidizing action. Besides antioxidants, antioxidants and light stabilizers conventionally known as additives for synthetic resins and the like can be mentioned. In this case, it may be contained in at least one of the heat transferable protective layers, that is, at least one of the release layer, the transparent resin layer, and the heat-sensitive adhesive layer, but is particularly preferably contained in the heat-sensitive adhesive layer.

  Examples of the antioxidant include primary antioxidants such as phenols, monophenols, bisphenols, and amines, and secondary antioxidants such as sulfur and phosphorus. Examples of the light stabilizer include hindered amines.

  Although the usage-amount of the light-proofing agent containing said ultraviolet absorber is not specifically limited, Preferably it is 0.05-10 mass parts per 100 mass parts of resin which forms the layer to contain, Preferably it is a ratio of 3-10 mass parts Used in. If the amount used is too small, it is difficult to obtain an effect as a light-proofing agent.

  In addition to the above light-proofing agent, various additives such as a fluorescent brightening agent and a filler can be added to the adhesive layer in an appropriate amount at the same time.

  The transparent resin layer of the protective layer transfer sheet may be provided alone on the substrate sheet, or may be provided in the surface order with the ink layer of the thermal transfer sheet.

(Heat resistant slipping layer)
In the thermal transfer sheet according to the present invention, it is preferable to provide a heat-resistant slipping layer on the surface opposite to the dye layer with the base sheet interposed therebetween.

  The heat resistant slipping layer is provided for the purpose of preventing thermal fusion between a heating device such as a thermal head and a base sheet, smooth running, and removing deposits on the thermal head.

  Examples of the resin used for the heat resistant slipping layer include cellulose resins such as ethyl cellulose, hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, cellulose acetate butyrate, and nitrocellulose, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, and polyvinyl. Vinyl resins such as acetal and polyvinyl pyrrolidone, acrylic resins such as polymethyl methacrylate, polyethyl acrylate, polyacrylamide, and acrylonitrile-styrene copolymers, polyimide resins, polyamide resins, polyamideimide resins, polyvinyltoluene resins, polymers A single or mixture of natural or synthetic resins such as malon indene resin, polyester resin, polyurethane resin, silicone-modified or fluorine-modified urethane is used. It is. In order to further improve the heat resistance of the heat resistant slipping layer, among the above resins, a resin having a hydroxyl group-based reactive group is used, and a polyisocyanate or the like is used in combination as a crosslinking agent. It is preferable to do.

  Further, in order to impart slidability with the thermal head, a solid or liquid release agent or lubricant may be added to the heat-resistant slip layer to give heat-resistant slip. Examples of release agents or lubricants include various waxes such as polyethylene wax and paraffin wax, higher aliphatic alcohols, organopolysiloxanes, anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants. Activators, fluorine surfactants, metal soaps, organic carboxylic acids and derivatives thereof, fluorine resins, silicone resins, fine particles of inorganic compounds such as talc, silica, and the like can be used. The amount of the lubricant contained in the heat resistant slipping layer is 5 to 50% by mass, preferably about 10 to 30% by mass. The thickness of such a heat-resistant slipping layer can be about 0.1 to 10 μm, preferably about 0.3 to 5 μm.

<Thermal transfer image-receiving sheet>
Next, a thermal transfer image receiving sheet comprising at least a substrate sheet and a dye receiving layer according to the present invention will be described.

(Substrate sheet)
The substrate sheet used in the thermal transfer image-receiving sheet has a role of holding the dye image-receiving layer, and since heat is applied during thermal transfer, it preferably has a mechanical strength that does not hinder handling even in an overheated state. .

  There are no particular limitations on the material of such a base material. For example, condenser paper, glassine paper, sulfuric acid paper, high-size paper, synthetic paper (polyolefin-based, polystyrene-based), high-quality paper, art paper, coated paper , Cast coated paper, wallpaper, backing paper, synthetic resin or emulsion impregnated paper, synthetic rubber latex impregnated paper, synthetic resin internal paper, paperboard, cellulose fiber paper, or polyester, polyacrylate, polycarbonate, polyurethane, polyimide, polyether Imide, cellulose derivative, polyethylene, ethylene-vinyl acetate copolymer, polypropylene, polystyrene, acrylic, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl butyral, nylon, polyether ether ketone, polysulfone, Examples include polyethersulfone, tetrafluoroethylene, perfluoroalkyl vinyl ether, polyvinyl fluoride, tetrafluoroethylene / ethylene, tetrafluoroethylene / hexafluoropropylene, polychlorotrifluoroethylene, and polyvinylidene fluoride. A white opaque film formed by adding a white pigment or a filler to these synthetic resins or a foamed foam sheet can be used, and is not particularly limited.

  Moreover, the laminated body by the arbitrary combinations of the said base material can also be used. Examples of typical laminates include cellulose fiber paper and synthetic paper, or synthetic paper of cellulose synthetic paper and a plastic film. The thickness of these substrate sheets may be arbitrary and is usually about 10 to 300 μm.

  In order to obtain higher printing sensitivity and high image quality without density unevenness or white spots, it is preferable to have a layer having fine voids. As the layer having fine voids, a plastic film or synthetic paper having fine voids inside can be used. Moreover, the layer which has a fine space | gap by various coating systems can be formed on various base material sheets. As a plastic film or synthetic paper having fine voids, polyolefin, especially polypropylene, is mainly blended with an inorganic pigment and / or a polymer incompatible with polypropylene, and these are used as void (void) formation initiators. A plastic film or synthetic paper obtained by stretching and forming a mixture of the above is preferable. If these are mainly polyester, etc., the viscoelastic or thermal properties make the cushioning and heat insulation properties inferior to those mainly made of polypropylene. Unevenness is also likely to occur.

Considering these points, the elastic modulus at 20 ° C. of the plastic film and synthetic paper is preferably 5 × 10 ⁸ Pa to 1 × 10 ¹⁰ Pa. In addition, since these plastic films and synthetic paper are usually formed by biaxial stretching, they shrink by heating. When these are left at 110 ° C. for 60 seconds, the shrinkage is 0.5 to 2.5%. The plastic film and the synthetic paper described above may be combined with each other as a single layer including fine voids, or may have a plurality of layers. In the case of a plurality of layer configurations, all layers constituting the layer may contain fine voids, or a layer having no fine voids may be contained. A white pigment may be mixed in the plastic film or synthetic paper as a concealing agent as necessary. In order to increase whiteness, an additive such as a fluorescent brightening agent may be included. The layer having fine voids preferably has a thickness of 30 to 80 μm.

  As a layer having fine voids, a layer having fine voids can be formed on a substrate by a coating method. As the plastic resin to be used, known resins such as polyester, urethane resin, polycarbonate, acrylic resin, polyvinyl chloride, and polyvinyl acetate can be used singly or in combination.

Further, if necessary, a resin such as polyvinyl alcohol, polyvinylidene chloride, polyethylene, polypropylene, modified polyolefin, polyethylene terephthalate, polycarbonate, or the like is provided on the surface of the substrate opposite to the side on which the image receiving layer is provided for the purpose of preventing curling. Or a layer of synthetic paper. As a bonding method, for example, known lamination methods such as dry lamination, non-solvent (hot melt) lamination, EC lamination method and the like can be used, but preferred methods are dry lamination and non-solvent lamination. Examples of the adhesive suitable for the non-solvent lamination method include Takenate 720L manufactured by Takeda Pharmaceutical Co., Ltd., and examples of the adhesive suitable for dry lamination include Takelac manufactured by Takeda Pharmaceutical Co., Ltd. Examples include A969 / Takenate A-5 (3/1), Polysol PSA SE-1400, Vinylol PSA AV-6200 series, manufactured by Showa High Polymer Co., Ltd., and the like. The amount of these adhesives, from about 1-8 g / m ² on a solids, and preferably from 2 to 6 g / m ^2.

  When a plastic film and synthetic paper as described above, or between them, or various types of paper and plastic film or synthetic paper are laminated, they can be bonded together by an adhesive layer.

  For the purpose of increasing the adhesive strength between the substrate sheet and the dye-receiving layer, it is preferable to subject the surface of the substrate sheet to various primer treatments and corona discharge treatments.

(Binder resin)
In the thermal transfer image-receiving sheet according to the present invention, a known binder resin can be used, and among them, a resin that is easily dyed is preferably used. Specifically, polyolefin resins such as polypropylene, halogenated resins such as polyvinyl chloride and polyvinylidene chloride, vinyl resins such as polyvinyl acetate and polyacrylate, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polystyrene Resins, polyamide resins, phenoxy resins, copolymers of olefins such as ethylene and propylene and other vinyl monomers, polyurethane, polycarbonate, acrylic resins, ionomers, cellulose derivatives, etc. Of these, polyester resins, vinyl resins and cellulose derivatives are preferred.

In the thermal transfer recording material of the present invention, the binder resin used in the thermal transfer image-receiving sheet has a glass transition temperature (Tg ₂ ) of at least one melting point (MP ₁₎ of the dye contained in the dye layer of the thermal transfer layer described above. ) And (MP ₁ -Tg ₂ ) is preferably -60 degrees to 60 degrees, more preferably (MP ₁ -Tg ₂ ) is -30 degrees to 30 degrees.

(Release agent)
It is preferable to add a release agent to the dye receiving layer according to the present invention for the purpose of preventing thermal fusion with the dye layer. As the mold release agent, a phosphoric ester plasticizer, a fluorine compound, silicone oil (including reaction curable silicone) and the like can be used, and among these, silicone oil is preferable. As the silicone oil, various modified silicones including dimethyl silicone can be used. Specifically, amino-modified silicones, epoxy-modified silicones, alcohol-modified silicones, vinyl-modified silicones, urethane-modified silicones, and the like can be blended or polymerized using various reactions. The release agent may be used alone or in combination of two or more. Further, the addition amount of the release agent is preferably 0.5 to 30 parts by mass with respect to 100 parts by mass of the binder resin for forming the dye image-receiving layer. When the range of the addition amount is not satisfied, there may be a problem such as fusion between the thermal transfer sheet and the dye image-receiving layer of the thermal transfer image-receiving sheet or a decrease in printing sensitivity. In addition, you may provide these mold release agents as a mold release layer separately on a dye receiving layer, without adding to a dye image receiving layer.

(Metal ion compound)
The dye-receiving layer according to the present invention preferably contains a metal ion-containing compound (hereinafter also referred to as a metal source).

Examples of the metal source include inorganic or organic salts and metal complexes of metal ions, and among them, salts and complexes of organic acids are preferable. Examples of the metal include monovalent and polyvalent metals belonging to Groups I to VIII of the Periodic Table. Among them, Al, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Sn, Ti And Zn are preferable, and Ni, Cu, Cr, Co and Zn are particularly preferable. Specific examples of the metal source include Ni ²⁺ , Cu ²⁺ , Cr ²⁺ , Co ²⁺ and Zn ²⁺ and aliphatic salts such as acetic acid and stearic acid, or aromatic carboxylic acids such as benzoic acid and salicylic acid. Examples include acid salts.

  In the present invention, the metal source is particularly preferably a complex represented by the following general formula (I) because it can be stably added to the binder resin in the post-heating region and is substantially colorless.

Formula (I)
[M (Q ₁ ) _X (Q ₂ ) _Y (Q ₃ ) _Z ] ^{P +} (L ⁻ ) _P
In the above general formula (1), M represents a metal ion, preferably Ni ²⁺ , Cu ²⁺ , Cr ²⁺ , Co ²⁺ or Zn ²⁺ . Q ₁ , Q _2, and Q ₃ each represent a coordination compound that can be coordinated to a metal ion represented by M, and may be the same or different from each other. These coordination compounds can be selected from, for example, coordination compounds described in Chelate Science (5) (Nan Edo). L ^- represents an organic anion group, and specific examples include tetraphenyl boron anion and alkylbenzene sulfonate anion. X represents 1, 2 or 3, Y represents 1, 2 or 0, and Z represents 1 or 0. P represents 1 or 2. Specific examples of this type of metal source include compounds exemplified in U.S. Pat. No. 4,987,049 or compound No. 9 exemplified in JP-A-9-39423. 1-99 etc. can be mentioned. Particularly preferred is a compound represented by the following general formula (II) described in JP-A-10-241410.

Formula (II)
M ²⁺ (X ₁ ^-) ₂
In the general formula (II), M ²⁺ represents a divalent transition metal ion, and among these, nickel and zinc are preferred from the color of the metal ion supply compound itself and the color tone of the chelated dye. X ₁ ^- represents a coordination compound capable of forming divalent metal ions and complexes. These compounds may have a neutral ligand depending on the central metal, and typical ligands include H ₂ O and NH ₃ .

(Middle layer)
The thermal transfer image receiving sheet may be provided with an intermediate layer between the base sheet and the dye receiving layer. The intermediate layer in the present invention refers to all layers existing between the base sheet and the dye-receiving layer, and may have a multilayer structure. Examples of the function of the intermediate layer include solvent resistance performance, barrier performance, adhesion performance, white color imparting ability, hiding performance, antistatic function, etc., but are not limited thereto, and all conventionally known intermediate layers can be applied. .

  In order to impart solvent resistance and barrier performance to the intermediate layer, it is preferable to use a water-soluble resin. Examples of water-soluble resins include cellulose resins such as carboxymethylcellulose, polysaccharide resins such as starch, proteins such as casein, gelatin, agar, and polyvinyl alcohol, ethylene vinyl acetate copolymer, polyvinyl acetate, vinyl chloride, Vinyl-based resins such as vinyl acetate copolymers (for example, Veopa manufactured by Japan Epoxy Resin Co., Ltd.), vinyl acetate (meth) acrylic copolymers, (meth) acrylic resins, styrene (meth) acrylic copolymers, and styrene resins. In addition, polyamide resins such as melamine resin, urea resin and benzoguanamine resin, polyester, polyurethane and the like can be mentioned. The water-soluble resin referred to here is completely dissolved (particle size of 0.01 μm or less), colloidal dispersion (0.01 to 0.1 μm), or emulsion (0.1 to 1 μm) in a solvent mainly composed of water. ) Or a resin in a slurry (1 μm or more) state. Of these water-soluble resins, particularly preferred are alcohols such as methanol, ethanol, and isopropyl alcohol, and dissolution with general-purpose solvents such as hexane, cyclohexane, acetone, methyl ethyl ketone, xylene, ethyl acetate, butyl acetate, and toluene. Of course, it is a resin that does not even swell. In this sense, a resin that is completely soluble in a solvent mainly composed of water is most preferable. In particular, a polyvinyl alcohol resin and a cellulose resin are mentioned.

  In order to give adhesive performance to the intermediate layer, a urethane-based resin and a polyolefin-based resin are generally used depending on the type of the base sheet and its surface treatment. Further, when a thermoplastic resin having active hydrogen and a curing agent such as an isocyanate compound are used in combination, good adhesiveness can be obtained. In order to give the intermediate layer a white color imparting ability, a fluorescent whitening agent can be used. The optical brightener used can be any conventionally known compound, including stilbene, distilbene, benzoxazole, styryl-oxazole, pyrene-oxazole, coumarin, aminocoumarin, imidazole, and benzimidazole. -Based, pyrazoline-based, and distyryl-biphenyl-based fluorescent whitening agents. The whiteness can be adjusted by the type and amount of the fluorescent brightener. Any method can be used as the method of adding the optical brightener. That is, a method of adding by dissolving in water, a method of adding by pulverizing and dispersing by a ball mill or a colloid mill, a method of dissolving in a high boiling point solvent and mixing with a hydrophilic colloid solution, and adding as an oil-in-water dispersion, There is a method of impregnating the polymer latex and adding it.

  Further, titanium oxide may be added to the intermediate layer in order to conceal the glaring feeling and unevenness of the base sheet. Furthermore, the use of titanium oxide is preferable in that the degree of freedom in selecting a base sheet is widened. There are two types of titanium oxide: rutile type titanium oxide and anatase type titanium oxide, but considering the effect of whiteness and fluorescent brightening agent, the absorption in the ultraviolet region is shorter than rutile type. Anatase type titanium oxide is preferred. If the binder resin in the intermediate layer is aqueous and titanium oxide is difficult to disperse, use titanium oxide with a hydrophilic treatment on the surface, or disperse it with a known dispersant such as a surfactant or ethylene glycol. be able to. As for the addition amount of a titanium oxide, 10-400 mass parts is preferable as a titanium oxide solid content with respect to 100 mass parts of resin solid content.

  In order to impart an antistatic function to the intermediate layer, a conventionally known conductive material such as a conductive inorganic filler or an organic conductive material such as polyaniline sulfonic acid may be appropriately selected and used in accordance with the intermediate layer binder resin. it can. The thickness of such an intermediate layer is preferably set in the range of about 0.1 to 10 μm.

  Next, a recording method using the thermal transfer recording material of the present invention will be described.

  An embodiment in the case where the thermal transfer protective layer or the post-heat treatment region is supplied in a surface sequence with the dye layer of the thermal transfer sheet will be described with reference to the drawings. FIG. 2 is a cross-sectional view showing an example of a mode in which one surface of the thermal transfer sheet according to the present invention is sequentially supplied. The thermal transfer sheet 21 in FIG. 2 includes dye layers 23Y, 23M, and 23C corresponding to yellow (Y), magenta (M), and cyan (C) dyes on the same plane of the base sheet, and the dye layer is separate from the dye layer. In this area, a heat transferable protective layer or a post-heat treatment area 23OP is provided in the surface order.

  In FIG. 2, a slight gap is provided between the dye layers, but a gap may be provided as appropriate in accordance with the control method of the thermal transfer recording apparatus. Further, in order to accurately locate each dye layer, it is preferable to provide a detection mark on the thermal transfer sheet, and the method of providing the detection mark is not particularly limited. Although each dye layer and thermal transferable protective layer or areas where post-heat treatment is performed are shown on the same plane of the base sheet, of course, each dye layer is provided on a separate base sheet. Needless to say. In addition, when a reactive dye is used for each dye layer, the dye itself contained in the dye layer is a compound before the reaction and strictly speaking, it cannot be said to be a Y, M, or C dye, In the sense of a layer for finally forming the M and C images, they are similarly expressed for convenience.

  In the present invention, particularly in chelate-type sublimation thermal transfer, post-heat treatment after dye transfer is preferably performed in order to terminate chelation after dye transfer. In this post-heat treatment step, it is preferable because a glossy image can be formed at the end of the reaction by heating with a thermal head so as to obtain a uniform heat distribution. Further, the post-heating treatment and the transfer of the heat transferable protective layer may be performed at the same time, and a glossy image can be formed by heating with a thermal head so as to obtain a uniform heat distribution in the process. .

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

<Production of thermal transfer sheet>
[Preparation of substrate sheet]
The surface of the polyethylene terephthalate film (Diafoil Hoechst Co., Ltd., K-203E-6F) that has been subjected to an easy adhesion treatment on one side having a thickness of 6 μm has a heat resistant slipping property having the following composition on the surface opposite the easy adhesion treatment surface After applying and drying the layer coating composition by a gravure coating method, heat curing treatment was performed to prepare a base sheet for a thermal transfer sheet having a heat-resistant slipping layer having a dry film thickness of 1 μm.

(Composition for heat resistant slipping layer application)
Polyvinyl butyral resin (Sekisui Chemical Co., Ltd., ESREC BX-1) 3.5 parts by mass Phosphate ester surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Prisurf A208S)
3.0 parts by mass Phosphate ester surfactant (Phosphanol RD720 manufactured by Toho Chemical Co., Ltd.)
0.3 part by mass Polyisocyanate (Bernock D750-45, manufactured by Dainippon Ink & Chemicals, Inc.)
19.0 parts by mass Talc (manufactured by Nippon Talc Co., Ltd. Y / X = 0.03) 0.2 parts by mass Methyl ethyl ketone 35 parts by mass Toluene 35 parts by mass [Preparation and Application of Dye Layer Coating Solution]
Next, on the surface opposite to the surface on which the heat-resistant slip layer of the polyethylene terephthalate film is formed, the dye layer coating liquids 1 to 12 having the composition shown in Table 1 are applied (dry solid content) by the wire bar coating method. 0.7 g / m ² ) and then dried at 100 ° C. for 1 minute to form each dye layer, and thermal transfer sheets 1 to 12 were produced.

  In addition, melting | fusing point (measured about one part dye) measured by DSC method and melting | fusing point of each dye used for preparation of the said thermal transfer sheets 1-12 are as follows.

Y1: Melting point = 93 ° C.
Y2: melting point = 170 ° C.
Y3: melting point = 70 ° C., heat of fusion = 84 J / g
M1: Melting point = 110 ° C., heat of fusion = 99 J / g
M3: Melting point = 161 ° C.
C1: Melting point = 111 ° C., heat of fusion = 69 J / g
C2: Melting point = 207 ° C. or more Details of each binder resin and solvent described in Table 1 are as follows.

KY-24: Polyvinyl butyral (manufactured by Denki Kagaku Kogyo Co., Ltd. KY-24 Tg = 103 ° C.)
BX-5: Polyvinyl acetal (manufactured by Sekisui Chemical Co., Ltd., BX-5 Tg = 86 ° C.)
BH-3: Polyvinyl acetal (Sekisui Chemical Co., Ltd. BH-3 Tg = 71 ° C.)
SP-2105: Urethane-modified silicone resin (Diaroma SP-2105 manufactured by Dainichi Seika Co., Ltd.)
* 1: Methyl ethyl ketone / toluene = 3/2 (mass ratio)

<< Preparation of thermal transfer image-receiving sheet >>
As a base sheet, the following intermediate layer coating solution is applied to one surface of a synthetic paper having a thickness of 150 μm (Yupo FPG-150 manufactured by Oji Oil Chemical Co., Ltd.) by a wire bar coating method. An undercoat layer having a dry solid content of 2.0 g / m ² was formed by drying at 0 ° C. for 1 minute.

Next, on the undercoat layer, each dye-receiving layer coating solution having the composition shown in Table 2 was applied by a wire bar coating method so that the dry solid content was 4 g / m ^2, and then heated to 110 ° C. And dried for 30 seconds to obtain thermal transfer image-receiving sheets 1 to 5.

[Intermediate layer coating solution]
35% aqueous solution of acrylic emulsion (Nicarbazole A-08, manufactured by Nippon Carbide Co., Ltd.) 5.7 parts by mass Pure water 94.0 parts by mass Details of each additive of the dye-receiving layer coating solution described in Table 2 Is as follows.

Resin 1: Vinyl chloride / vinyl acetate copolymer (vinyl chloride / vinyl acetate = 95/5 Tg = 78 ° C.)
Resin 2: Vinyl chloride / vinyl acetate copolymer (vinyl chloride / vinyl acetate = 76/24
Tg = 56 ° C)
Resin 3: Vinyl chloride / vinyl acetate copolymer (vinyl chloride / vinyl acetate = 25/75
Tg = 34 ° C)
Metal ion-containing compound: Ni ²⁺ [C ₇ H ₁₅ COC (COOCH ₃ ) O ⁻ ] ₂
Silicone 1: Epoxy-modified silicone (X-22-8300T manufactured by Shin-Etsu Chemical Co., Ltd.)
Silicone 2: Epoxy-modified silicone (KF-393 manufactured by Shin-Etsu Chemical Co., Ltd.)
Silicone 3: amino-modified silicone (KF-343, manufactured by Shin-Etsu Chemical Co., Ltd.)
* 2: Methyl ethyl ketone / toluene = 1/1 (mass ratio)

<< Image formation and evaluation >>
(Image formation)
The above-described fabrication was carried out on a thermal transfer apparatus equipped with a thermal head having a resistor shape of square (main scanning direction length 80 μm × sub-scanning direction length 120 μm), 300 dpi (hereinafter, dpi represents the number of dots per 2.54 cm) line head. An applied energy range of 5 to 80 mJ / mm ² while the dye receiving layer portion of the thermal transfer image-receiving sheet and the dye layer of the thermal transfer sheet are set to overlap each other according to the combinations shown in Table 3 and pressed with a thermal head and a platen roll. Steps that are sequentially increased at a feed rate of 10 msec / line, a feed length per line of 85 μm, heated from the back side of the ink layer to transfer the dye onto the dye receiving layer, and images 1 to 20 Created.

[Evaluation of formed image]
After printing as described above, the dye transfer property and the print density of the thermal transfer image-receiving sheet and its print were evaluated according to the following methods.

(Evaluation of dye transferability)
About the thermal transfer sheet after printing produced as mentioned above, the transmission optical density after printing was measured using the densitometer (X-rite310 status A). The measurement was carried out by applying energy ^{20mJ / mm 2, 40mJ / mm} 2, 60mJ / mm 2 of the 3 conditions. Next, the transfer rate was calculated according to the following equation from the transmission density before printing and the transmission density after printing.

Transfer rate = {(Transmission density before printing−Transmission density after printing) / (Transmission density before printing)} × 100 (%)
Next, for each transfer rate obtained, images 1 to 5 created using the thermal transfer sheets 1 to 3 having the dye (Y-1) are based on the image 6 (comparative example), and the dye (M-1) is used as a reference. Images 7 to 15 created using the thermal transfer sheets 5 to 7 having images 17 to 19 based on the sample 16 (comparative example) and using the thermal transfer sheets 9 to 11 containing the dye (C-1) Determined the relative transfer rate based on Sample 20 (Comparative Example), and evaluated dye transferability according to the following criteria.

A: The transfer rate is 110% or more with respect to the transfer rate of the comparative example as a reference. O: The transfer rate is 100% or more and less than 110% with respect to the transfer rate of the comparative example as a reference. The transfer rate is 90% or more and less than 100% with respect to the transfer rate of the comparative example to be ×: The transfer rate is less than 90% with respect to the transfer rate of the reference comparative example (evaluation method for print density)
The printed matter prepared as described above was measured for optical reflection density (OD) with a Macbeth reflection densitometer (manufactured by GretagMachbeth) and evaluated according to the following criteria.
Evaluation criteria That is, the prints (images 1 to 5) prepared using the thermal transfer sheets 1 to 3 having the dye (Y-1) are based on the sample 6 (comparative example) and have the dye (M-1). The prints (images 7 to 15) created using the thermal transfer sheets 5 to 7 are based on the sample 16 (comparative example), and are printed using the thermal transfer sheets 9 to 11 having the dye (C-1). For the objects (images 17 to 19), the image density was evaluated according to the following criteria with reference to the sample 20 (comparative example).

◎: OD is 110% or more in the same step as the step of OD≈1.0 of the reference comparative example ○: OD is 100 in the same step as the step of OD≈1.0 of the reference comparative example %: Less than 110% Δ: OD is 90% or more and less than 100% in the same step as that of the reference comparative example OD≈1.0 ×: The reference comparative example OD≈1. Table 3 shows the results obtained when the OD is less than 90% in the same step as step 0.

  As is apparent from the results in Table 3, an image formed using a dye having the melting point specified in the present invention, or a thermal transfer sheet in which the difference between the melting point of the dye and the Tg of the binder resin satisfies the conditions specified in the present invention, or It was confirmed that the printed matter had a sufficient printing density and excellent dye transferability as compared to the comparative example.

It is sectional drawing which shows an example of a structure of the thermal transfer sheet and thermal transfer image receiving sheet which comprise the thermal transfer recording material of this invention. It is sectional drawing which shows an example of the form supplied one surface sequentially of the thermal transfer sheet which concerns on this invention.

Explanation of symbols

1, 21 Thermal transfer sheet 2, 12, 22 Base sheet 3, 23Y, 23M, 23C Dye layer 23OP Thermal transfer protective layer or post-heat treatment region 4 Heat resistant slip layer 11 Thermal transfer image receiving sheet 13 Dye receiving layer 23Y, 23M, 23C Dye layer

Claims (11)

Consists of a thermal transfer sheet having a dye layer on at least one side of the base sheet and a thermal transfer image receiving sheet having a dye receiving layer on at least one side of the base sheet, and the dye layer and the receiving layer are overlaid Thereafter, in the thermal transfer recording material capable of transferring the dye in the dye layer to the dye receiving layer by a heating means, the dye layer contains a dye and a binder resin, and at least one melting point (MP A thermal transfer recording material characterized in that ₁ ) is 130 ° C. or lower. 2. The thermal transfer recording material according to claim 1, wherein at least one melting point (MP ₁ ) of the dye is 70 ° C. or less. A thermal transfer sheet having a dye layer on at least one side of the base sheet and a thermal transfer image receiving sheet having a dye receiving layer on at least one side of the base sheet, the dye layer and the dye receiving layer being stacked In the thermal transfer recording material in which the dye in the dye layer can be transferred to the dye receiving layer by heating means after combining, the dye layer contains a dye and a binder resin, and at least one melting point (MP ₁ ) is 130 ° C. or lower, and the difference (Tg ₁ −MP ₁ ) between the glass transition temperature (Tg ₁ ) of the main binder constituting the binder resin and the melting point (MP ₁ ) of the dye is 0 ° C. or higher. A thermal transfer recording material characterized by being. The difference (Tg ₁ -MP ₁ ) between the glass transition temperature (Tg ₁ ) of the main binder constituting the binder resin and the melting point (MP ₁ ) of the dye is 15 ° C. or more. The thermal transfer recording material described. The difference (Tg ₁ -MP ₁ ) between the glass transition temperature (Tg ₁ ) of the main binder constituting the binder resin and the melting point (MP ₁ ) of the dye is 30 ° C. or more. The thermal transfer recording material described. The thermal transfer recording material according to claim 3, wherein at least one melting point (MP ₁ ) of the dye is 70 ° C. or less. The thermal transfer recording material according to claim 3, wherein the heat of fusion of at least one of the dyes is 110 J / g or less. At least one melting point (MP ₁ ) of the dye contained in the dye layer of the thermal transfer sheet and the glass transition temperature (Tg ₂ ) of the main binder constituting the binder resin contained in the dye receiving layer of the thermal transfer image-receiving sheet The thermal transfer recording material according to claim 3, wherein the difference (MP ₁ −Tg ₂ ) is −60 degrees to 60 degrees. At least one melting point (MP ₁ ) of the dye contained in the dye layer of the thermal transfer sheet and the glass transition temperature (Tg ₂ ) of the main binder constituting the binder resin contained in the dye receiving layer of the thermal transfer image-receiving sheet The thermal transfer recording material according to claim 3, wherein the difference (MP ₁ −Tg ₂ ) is −30 degrees to 30 degrees. The thermal transfer recording material according to any one of claims 1 to 9, wherein the dye-receiving layer contains a metal ion-containing compound that can react with a dye to form a chelate compound. The thermal transfer recording material according to claim 10, wherein the dye is a dye capable of forming a chelate by reacting with a metal ion-containing compound.

Images