JP2005313359A - Thermal transfer ink sheet and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal transfer ink sheet which can prevent fogging with time and can bring about an image excellent in density and sensitivity, and an image forming method. <P>SOLUTION: This thermal transfer ink sheet, where an ink layer containing at least a thermally diffusible dye is provided on a substrate, is characterized in that a surface-active agent with an HLB of 10 or more is contained in the ink layer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to a thermal transfer ink sheet used for dye thermal transfer recording and an image forming method using the same, and more particularly, a thermal transfer ink sheet having good storage stability and an image having good sensitivity and density, and an image forming method using the thermal transfer ink sheet. About.

  Conventionally, as a color or monochrome image forming technique, an ink sheet containing a thermal diffusible dye having a property of diffusing and transferring by heating is opposed to an image receiving layer of an image receiving sheet, and a thermal printing means such as a thermal head or a laser is used. A technique (so-called dye thermal transfer method) is known in which an image is formed by transferring the thermal diffusible dye imagewise to the image receiving layer. Such a thermal transfer method is well-established as a method that enables image formation using 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.

  However, the thermal transfer ink sheet used in the dye thermal transfer system has a problem in storage stability. That is, in conventional thermal transfer ink sheets, the thermal diffusible dye is deposited on the surface of the ink layer by storage, and the surface of the image receiving sheet is contaminated with a dye during printing, and the portion without white image data (white background portion) is also colored. The phenomenon of so-called fogging that occurred was sometimes occurring.

  As a technique for improving the storage stability, in Patent Document 1, the cause of storage stability deterioration is that the disperse dye is dissolved or finely dispersed in the binder in the heat transfer ink sheet that is generally used. In order to heat and sublimate dye molecules in such a state, dye aggregation, crystal growth, and precipitation occur in the resin, and the heat within the interaction between the dye aggregate and the crystal is broken and the interaction with the binder resin is exceeded. Energy must be applied to the dye molecules and sublimated and dyed onto the thermal transfer ink sheet, which requires high energy, resulting in low thermal sensitivity of the thermal transfer ink sheet and deposition on the surface It is considered that the transferred material is contaminated by the dye thus obtained, and as a solution to this, a binder containing a dye that is transferred to the transferred material by transfer onto the substrate sheet by heating A thermal transfer layer made of fat is laminated, and the molecular weight of the binder resin is 60,000 to 200,000, the glass transition temperature is 60 to 110 ° C., and the polyvinyl butyral resin is 10% by mass to 90% by mass. By including the above, aggregation over time, crystal growth and precipitation of the dye in the thermal transfer layer are prevented, and a high density and clear image is formed with relatively low energy without causing background staining.

  Further, as another storability improvement technique, in Patent Document 2, the cause of storability deterioration is that the heat-sublimable dye molecule has a relatively small molecular weight of about 150 to 550 and is easy to move in a binder. When a binder having a low transition temperature (Tg) is used, development occurs that aggregates and precipitates over time, and the dye is dispersed in the form of particles, or bleeds to the surface of the thermal transfer layer. As a result, during recording, the pressure between the thermal head and the platen (platen) causes the dye to adhere to the surroundings of the heated part, causing scumming and significantly reducing the image quality. A thermal transfer ink sheet in which a thermal transfer layer containing a dye that is transferred by heating and transferred onto a transfer paper is laminated on a substrate sheet, wherein the thermal transfer layer is a binder component In particular, the polyvinyl acetoacetal resin as the binder component contains 50% or more by mass of the acetal part based on the total amount of the polymer, and more than 80% by mass of the acetal part. It is made of polyvinyl acetoacetal, and the dye used is a disperse dye. The disperse dye is substantially dissolved in the binder, so that the storage stability is improved.

  However, even with these techniques, the improvement in storage stability was not sufficient.

Further, as a technique for containing a surfactant in the ink layer, JP-A 1-20090 discloses a phosphoric ester surfactant as a release agent, and JP-A-4-218787 discloses a fluorine-based surfactant as an oil resistance improver for images. JP-A-2-289384 discloses a cationic surfactant as an antistatic agent, an anionic surfactant and a nonionic surfactant, JP-A-4-118288 discloses a fluorine-based surfactant as a leveling agent, JP-A-7- No. 290847 mentions the use of various surfactants as dispersants. The purpose of use of these surfactants is to release agents, improve oil resistance, etc. as described above. Absent. In addition, it is known that a surfactant is contained in the ink layer, but the prior art that defines the HLB is not known.
Japanese Examined Patent Publication No. 4-41679 Japanese Patent No. 2515310

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a thermal transfer ink sheet and an image forming method capable of preventing fogging with time and obtaining an image having excellent density and sensitivity. .

  The above object of the present invention is achieved by the following configurations.

(Claim 1)
A thermal transfer ink sheet having an ink layer containing at least a heat diffusible dye on a support, wherein the ink layer contains a surfactant having an HLB of 10 or more.

(Claim 2)
The thermal transfer ink sheet according to claim 1, wherein the surfactant has an HLB of 12 or more.

(Claim 3)
The thermal transfer ink sheet according to claim 1 or 2, wherein an addition amount of the surfactant in the ink layer is 1% by mass or more.

(Claim 4)
The thermal transfer ink sheet according to any one of claims 1 to 3, wherein the thermal diffusible dye is capable of forming a chelate complex with a metal ion-containing compound.

(Claim 5)
An image forming method using the thermal transfer ink sheet and the thermal transfer image receiving sheet according to claim 1.

  According to the present invention, it is possible to provide a thermal transfer ink sheet and an image forming method capable of preventing fogging with time and obtaining an image having excellent density and sensitivity.

  As a result of diligent research, the present inventor has found that a thermal transfer ink sheet having an ink layer containing at least a heat diffusible dye on a support contains a surfactant having an HLB of 10 or more in the ink layer. It has been found that a thermal transfer ink sheet can be obtained which can prevent fogging and can obtain an image having excellent density and sensitivity.

  The present invention will be described in detail below.

[Surfactant with HLB of 10 or more]
In the present invention, a surfactant having an HLB of 10 or more is used for the ink layer of the thermal transfer ink sheet.

In general, an HLB value indicating a balance between hydrophilicity and lipophilicity is known as a quantitative measure of the emulsification characteristics of a surfactant. Several empirical formulas proposed so far can be used to calculate the HLB value. For example,
In the case of polyhydric alcohol fatty acid ester,
HLB = 20 (1-S / A) However, S: Saponification value of ester, A: Acid value of fatty acid In the case of tall oil, pine oil, beeswax, lanolin polyhydric alcohol,
HLB = (E + P) / 5 where E: oxyethylene content (%), P: polyhydric alcohol content (%)
In the case of polyoxyethylene type nonionic surfactant (one that does not contain other hydrophilic groups)
HLB = E / 5
Further, the HLB of the surfactant obtained by mixing the surfactant a of HLBa and the surfactant b of HLBb is
HLB = {(Wa × HLBa) + (Wb × HLBb)} / (Wa + Wb)
However, it can represent with Wa: the mass fraction of the active agent a, and Wb: the mass fraction of the active agent b. In the present invention, the HLB value calculated by these equations is used.

  Examples of the surfactant having an HLB value of 10 or more used in the present invention include the following. That is, as the nonionic surfactant, polyoxyethylene lauryl ether (HLB value = 10.5 to 16.3), polyoxyethylene stearyl ether (13.9), polyoxyethylene oleyl ether (10.0 to 16.2), polyoxyethylene higher alcohol ether (12.1 to 13.3), polyoxyethylene nonylphenyl ether (10.8 to 18.9), polyoxyethylene derivative (12.8 to 13.2) , Polyoxyethylene lauryl ether (16.9), polyoxyethylene sorbitan monolaurate (13.3 to 16.7), polyoxyethylene sorbitan monopalmitate (15.6), polyoxyethylene sorbitan monostearate ( 14.9), polyoxyethylene sorbitan tristearate (1 .5), polyoxyethylene sorbitan monooleate (10.0 to 11.0), polyethylene glycol monolaurate (13.7), polyethylene glycol monostearate (13.4 to 19.1), polyethylene glycol di Stearates (18.3), polyethylene glycol monooleate (11.6), polyoxyethylene sorbitol tetraoleate (10.5 to 13.8) and the like, and as the anionic surfactant, triethanol is used. Amine oleate (12), sodium oleate (18), potassium oleate (20) and the like. These surfactants are commercially available and can be easily obtained.

  In the present invention, the HLB of the surfactant is preferably 12 or more, and more preferably 13 or more. The addition amount of the surfactant in the ink layer is preferably 1% by mass or more, and more preferably 3% by mass or more.

<Thermal transfer ink sheet>
The thermal transfer ink sheet according to the present invention has each dye layer containing a dye and a peelable protective transfer layer.

  FIG. 1 is a perspective view showing an example of a form of a thermal transfer ink sheet according to the present invention. In FIG. 1, the thermal transfer ink sheet 11 is formed with dye layers 13Y, 13M, and 13C corresponding to yellow (Y), magenta (M), and cyan (C) dyes on the same plane of the base sheet 12. A protective transfer layer unit 14 including a peelable protective transfer layer is provided in a region separate from the dye layer. The protective transfer layer unit 14 is configured on a base sheet 12 in the order of a non-transferable release layer 15, a protective transfer layer 16, and an adhesive layer 17. The other surface of the base sheet 2 is provided with a heat-resistant slip layer 18. The protective transfer layer 16 may be a laminate of a protective layer and an adhesive layer.

In FIG. 1, there are slight gaps between the dye layers or the protective transfer layer units 14, but the gaps may be appropriately adjusted according to the control method of the thermal transfer recording apparatus. Further, in order to increase the accuracy of cueing each dye layer, it is preferable to provide the detection mark on the thermal transfer ink sheet, and the method of providing the detection mark is not particularly limited. Although a dye layer and a heat transferable protective transfer layer or a region where post-heat treatment is performed are shown on the same plane of the base sheet, of course, each layer may be provided on a separate support. 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 Y, M, or C dye, but Y, M In the sense that it is the layer for finally forming the C image, it is expressed in the same way for convenience. [Support]
As the support used for the thermal transfer ink sheet according to the present invention, conventionally known materials can be used as the support (substrate sheet) for the thermal transfer ink sheet. Specific examples of preferable supports include thin papers such as glassine paper, condenser paper, and 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 and other plastic stretched or unstretched films, and these materials were laminated Things. The thickness of the support 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 support is poor, it is preferable to perform primer treatment or corona treatment on the surface.

[Dye layer]
The dye layer constituting the thermal transfer ink sheet according to the present invention is a heat sublimable colorant layer containing at least a dye and a binder resin.

<dye>
The dye-containing region used in the thermal transfer ink sheet according to the present invention can be two or more dye-containing regions that differ in hue. For example, the dye-containing region includes a yellow dye-containing region, a magenta dye-containing region, and An embodiment in which a dye-free region is formed next to a region containing a cyan dye, and a dye-free region is formed from an ink layer containing a black dye; And the dye-containing region is composed of a region containing a yellow dye, a region containing a magenta dye, a region containing a cyan dye, and a region containing a black dye. Examples include an embodiment in which a non-containing region is formed.

  The dyes used in the heat sublimation colorant layer are all dyes such as azo, azomethine, methine, anthraquinone, quinophthalone, and naphthoquinone that are used in heat transfer ink sheets of the conventional heat-sensitive sublimation transfer method. There are no particular restrictions. Specific examples of yellow dyes include Holon Brilliant Yellow 6GL, PTY-52, Macrolex Yellow 6G, etc., and red dyes include MS Red G, Macrolex Red Violet R, Ceres Red 7B, Samaron Red HBSL, and SK. Rubin SEGL and the like, and as blue dyes, Kayaset Blue 714, Waxoline Blue AP-FW, Holon Brilliant Blue S-R, MS Blue 100, Daito Blue No. 1 etc. are mentioned.

  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 Use cyan dye, magenta dye, yellow dye, etc. described in JP-A No. 59-109349, JP-A-4-94974, JP-A-4-97894, and Patent No. 2,856,225. can do.

  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 represent 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, an i-propyl group, and the like, and examples of the 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 groups (for example, 2-tetrahydrofuryl group, 2-thiophenyl group, 4-imidazolyl group, 2-pyridyl group, etc.), Logen 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 group Heterocyclic oxycarbonyl group, etc.), carbamoyl group (eg, dimethylcarbamoyl group, alkylcarbamoyl group such as 4- (2,4-di-t-amylphenoxy) butylaminocarbonyl group, phenylcarbamoyl group, 1-naphthylcarbamoyl) Arylcarbamoyl group such as a 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, pivaloyloxy) Alkylcarbonyloxy groups such as benzoyl Aryloxy groups such as ruoxy groups and pentafluorobenzoyloxy groups), urethane groups (for example, alkylurethane groups such as N, N-dimethylurethane groups, N-phenylurethane groups, N- (p-cyanophenyl) urethane groups. 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 (eg Methanesulfonylamino group, heptafluoropropanesulfonylamino group, alkylsulfonylamino group such as n-hexadecylsulfonylamino group, p-toluenesulfonylamino group, arylsulfonylamino group such as pentafluorobenzenesulfonylamino, etc.), sulfa Moylamino group (eg, alkylsulfamoylamino group such as N, N-dimethylsulfamoylamino group, arylsulfamoylamino group such as N-phenylsulfamoylamino group), acylamino group (eg, acetyl) Amino groups, alkylcarbonylamino groups such as myristoylamino groups, arylcarbonylamino groups such as benzoylamino groups, etc., ureido groups (eg, alkylureido groups such as N, N-dimethylaminoureido groups, N-phenylureido) , 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, etc.) Sulfamoyl groups (eg, dimethylsulfamoyl groups, alkylsulfamoyl groups such as 4- (2,4-di-t-amylphenoxy) butylaminosulfonyl group, and arylsulfamoyl groups such as phenylsulfamoyl group) Etc.), alkylthio groups (for example, methylthio group, t-octylthio group, etc.), arylthio groups (for example, phenylthio group, etc.), heterocyclic thio groups (for example, 1-phenyltetrazol-5-thio group, 5-methyl-1) , 3,4-oxadiazole-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 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 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, examples of preferred secondary or tertiary alkyl groups isopropyl, sec- butyl group, tert- butyl group, 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, examples of which include n- propyl group, n- butyl group, n- pentyl group, n- hexyl group, heptyl group n-, isopropyl, 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 of 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 condensed rings 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 ink sheet of a conventionally known heat-sensitive sublimation transfer method can be used. For example, cellulose resins such as cellulose addition compounds, cellulose esters, and cellulose ethers. , Polyvinyl acetal resins such as polyvinyl alcohol, polyvinyl formal, polyvinyl acetoacetal, polyvinyl butyral, polyvinyl pyrrolidone, polyvinyl acetate, polyacrylamide, styrene resin, poly (meth) acrylic acid ester, poly (meth) acrylic acid, ( Examples thereof include vinyl resins such as (meth) acrylic acid copolymers, rubber resins, ionomer resins, olefin resins, and polyester resins. Among these resins, polyvinyl butyral, polyvinyl acetoacetal or cellulose resin having excellent storage stability is preferable.

  As a binder resin for the dye layer, a reaction product of an isocyanate described in JP-B-5-78437 and a compound having active hydrogen selected from polyvinyl butyral, polyvinyl formal, polyester polyol and acrylic polyol, isocyan 10 to 200 parts by mass of the above reaction product with respect to 100 parts by mass of the above reaction product in which the natates are diisocyanate or triisocyanate and a compound having active hydrogen; natural and / or semi-synthetic water-soluble An organic solvent-soluble polymer obtained by esterification and / or urethanization of an intramolecular hydroxyl group of a polymer; a natural and / or semi-synthetic water-soluble polymer; the degree of acetylation described in JP-A-3-264393 is 2.4 or more and Cellulose acetate having a total substitution degree of 2.7 or more; polyvinyl alcohol (Tg = 8 ° C), polyvinyl acetate (Tg = 32 ° C), vinyl resin such as vinyl chloride / vinyl acetate copolymer (Tg = 77 ° C), polyvinyl butyral (Tg = 84 ° C), polyvinyl acetoacetal (Tg = 110 ° C) Polyvinyl acetal resins such as polyacrylamide (Tg = 165 ° C.), vinyl resins such as aliphatic polyester (Tg = 130 ° C.), and the like; isocyanates described in JP-A-7-52564; A reaction product with polyvinyl butyral in which the mass of the vinyl alcohol moiety contained is 15 to 40%, the reaction product in which the isocyanate is a diisocyanate or a triisocyanate; described in JP-A-7-32742 Phenylisocyanate-modified polyvinyl acetal resin of general formula (I); JP-A-6-155935 One of the isocyanate-reactive cellulose or isocyanate-reactive acetal resin described in 1), an isocyanate-reactive acetal resin, an isocyanate-reactive vinyl resin, an isocyanate-reactive acrylic resin, an isocyanate-reactive phenoxy resin, and an isocyanate Cured product of composition containing one kind of resin selected from reactive styrene resin and polyisocyanate compound; polyvinyl butyral resin (preferably having a molecular weight of 60,000 or more, glass transition temperature of 60 ° C. or more, more preferably 70 ° C. 110 ° C. or less, and the mass% of the vinyl alcohol portion is 10 to 40%, preferably 15 to 30% in the polyvinyl butyral resin); acrylic modified cellulose resin and cellulose resin include ethyl cellulose, hydroxyethyl cellulose, ethylene Cellulose-based resins (preferably ethyl cellulose) such as ruhydroxycellulose, hydroxypropylcellulose, methylcellulose, cellulose acetate, and cellulose butyrate can be used.

  One of these various binder resins can be used alone, or two or more thereof can be used in combination.

  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 transfer layer)
The thermal transfer ink sheet according to the present invention preferably includes a peelable protective transfer layer. The peelable protective transfer layer is a protective layer that covers the surface of the image formed by thermal transfer on the image receiving sheet, and is mainly composed of a transparent resin layer.

  Examples of the resin forming the protective transfer 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, 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 protective transfer layer, and 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 transfer 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.

  In the present invention, as a method for forming a protective transfer layer on a substrate sheet, a coating solution in which additives such as an antistatic agent and wax are added to a synthetic resin as necessary is prepared. Examples of the method include coating and drying on a release layer already formed on a sheet using a known means such as gravure coating, gravure reverse coating, and roll coating. The thickness of the protective transfer layer to be formed is about 0.5 to 5 μm, preferably about 1 to 2 μm.

(Release layer)
The peelable protective transfer layer according to the present invention is preferably provided on the base sheet via a non-transferable release layer.

  The non-transfer mold release layer always makes the adhesive force between the base sheet and the non-transfer mold release layer sufficiently higher than the adhesive force between the non-transfer mold release layer and the protective transfer layer, For the purpose of increasing the adhesive force between the non-transferring release layer before applying heat and the protective transfer layer relative to that after applying heat, (1) together with the resin binder, the average particle diameter Contains 30 to 80% by mass of inorganic fine particles of 40 nm or less, or (2) contains 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) The ionomer is preferably contained 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 it exceeds 40 nm, the unevenness on the surface of the protective transfer layer is increased due to the unevenness on the surface of the release layer, and as a result, the transparency of the protective transfer 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 transfer 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 moiety is a methyl group or an ethyl group, and the maleic anhydride moiety 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 transfer layer, other layers may be used. These resins or fine particles may be further added. In that case, it is desirable that the release layer 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. be able to. 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 protective transfer layer laminated on the base sheet with or without the non-transfer 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 transfer layer as a main component for imparting various durability to the image, a protective transfer layer is used to increase the adhesion between the protective transfer layer and the image receiving surface of the printed material. May be provided with an adhesive layer disposed on the outermost surface, an auxiliary protective transfer layer, or a layer for adding a function other than the original function of the protective transfer layer (for example, an anti-counterfeit layer, a hologram layer). . The order of the main protective transfer layer and the other layers is arbitrary, but in general, other layers are provided between the adhesive layer and the main protective transfer layer so that the main protective transfer layer becomes the outermost surface of the image receiving surface after transfer. Place.

[Adhesive layer]
An adhesive layer is preferably formed on the outermost surface of the protective transfer layer. The adhesive layer should 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, polyamide resin. Can do. 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 protective transfer layer on a non-transferable release layer or on a substrate sheet, for example, a protective transfer layer coating solution containing a protective transfer layer forming resin, or an adhesive layer containing a thermal adhesive resin A coating solution for forming a coating solution and other layers to be added according to need 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.

[Others]
<UV absorber>
It is preferable that at least one layer of the protective transfer layer unit (peeling layer, protective transfer layer and adhesive layer) contains an ultraviolet absorber, but when it is contained in the transparent resin layer, after the transfer of the protective transfer layer Since the transparent resin layer is present on the outermost surface of the printed material, the effect is reduced over time due to the influence of the environment and the like over a long period of time. Therefore, the transparent resin layer is particularly preferably contained in the heat-sensitive adhesive layer.

  Examples of the ultraviolet absorber include salicylic acid-based, benzophenone-based, benzotriazole-based, and cyanoacrylate-based ultraviolet absorbers. Specifically, for example, Tinuvin P, Tinuvin 234, Tinuvin 320, Tinuvin 326, Tinuvin 327, Tinuvin 328 , Tinuvin 312, Tinuvin 315 (above, manufactured by Ciba Geigy), Sumisorb-110, Sumisorb-130, Sumisorb-140, Sumisorb-200, Sumisorb-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, Adeka Argus Chemical Co., Ltd.) available on the market under the trade names such as, any 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 absorber is a conventionally known salicylate-based, benzophenone-based, benzotriazole-based, substituted acrylonitrile-based, nickel chelate-based, hindered amine-based non-reactive ultraviolet absorber, for example, vinyl group, acryloyl group, 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-described 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.

<Light resistance>
In addition to the ultraviolet absorber, another light-proofing agent may be included. 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 altering or decomposing the dye, such as light energy, thermal energy, and oxidizing action. Besides antioxidants, antioxidants and light stabilizers known as additives for conventional synthetic resins and the like can be mentioned. In this case, it may be contained in at least one of the protective transfer 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.

<Antioxidant>
Examples of the antioxidant include primary antioxidants such as phenols, monophenols, bisphenols, and amines, or 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, while if it is too large, it is not economical.

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

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

[Heat resistant slipping layer]
In the thermal transfer ink 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 material 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 provide heat-resistant slip. Examples of release agents or lubricants include various waxes such as polyethylene wax and paraffin wax, higher aliphatic alcohols, organopolysiloxanes, organic carboxylic acids and derivatives thereof, fluorine resins, silicone resins, talc, silica, and the like. Fine particles of inorganic compounds 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.

  When the protective transfer layer unit is a laminate of a protective transfer layer and an adhesive layer, the adhesive layer serves to facilitate the transfer of the protective transfer layer to the transfer target. As an adhesive for forming this adhesive layer, it is possible to use a hot-melt adhesive such as acrylic, styrene acrylic, vinyl chloride, styrene-vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer. it can. The adhesive layer can be formed by known means such as gravure coating, gravure reverse coating, roll coating, etc., and the thickness of the adhesive layer is preferably about 0.1 to 5 μm.

<Thermal transfer image-receiving sheet>
Next, a thermal transfer image receiving sheet having at least a heat diffusible dye receiving layer on the support according to the present invention will be described.

(Substrate sheet)
The support used in the thermal transfer image-receiving sheet has a role of holding the heat-diffusible dye image-receiving layer and has a mechanical strength that does not hinder handling even in an overheated state because heat is applied during thermal transfer. Is preferred.

  The material of such a support is not particularly limited. For example, condenser paper, glassine paper, sulfuric acid paper, high-size paper, synthetic paper (polyolefin-based, polystyrene-based), fine 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 polyether sulfone, 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 support body can also be used. As an example of a typical laminated body, the synthetic paper of a cellulose fiber paper and a synthetic paper or a cellulose synthetic paper and a plastic film is mentioned. 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. In the case of those mainly composed of polyester or the like, the cushioning property and heat insulation are inferior to those mainly composed of polypropylene due to their viscoelastic or thermal properties, so that the printing sensitivity is inferior and the density unevenness is inferior. Etc. are also likely to occur.

Considering these points, the elastic modulus at 20 ° C. of the plastic film and the synthetic paper is preferably 5 × 10 ⁸ 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 or synthetic paper described above may itself be a single layer including a fine void or may have a plurality of layer configurations. In the case of a plurality of layer structures, all the layers constituting the structure may contain fine voids, or a layer containing 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. Further, 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.

In addition, 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 support opposite to the side on which the image receiving layer is provided for the purpose of preventing curling. And 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 laminating a plastic film and synthetic paper as described above, or between them, or various papers and a plastic film or synthetic paper, they can be bonded together with an adhesive layer.

  For the purpose of increasing the adhesive strength between the substrate sheet and the heat diffusible 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 with other vinyl monomers, polyurethane, polycarbonate, acrylic resins, ionomers, cellulose derivatives, etc. Of these, polyester resins, vinyl resins and cellulose derivatives are preferred.

(Release agent)
It is preferable to add a release agent to the heat diffusible dye receiving layer according to the present invention for the purpose of preventing heat fusion with the heat diffusible dye receiving 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, problems 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 may occur. In addition, you may provide these mold release agents as a mold release layer separately on a heat | fever diffusible pigment | dye receiving layer, without adding to a dye image receiving layer.

(Metal ion compound)
The heat-diffusible dye-receiving layer according to the present invention preferably contains the same metal ion-containing compound as that used in the resin layer of the transferable image protective layer unit.

(Middle layer)
The thermal transfer image receiving sheet may be provided with an intermediate layer between the base sheet and the heat diffusible dye receiving layer. The intermediate layer referred to in the present invention refers to all layers existing between the base sheet and the heat-diffusible 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 carboxymethyl cellulose, 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.

  Furthermore, titanium oxide may be added to the intermediate layer in order to conceal the glare of the base sheet and unevenness. 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 whitening 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 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.

(Image forming method)
As the thermal transfer recording apparatus used in the image forming method of the present invention, for example, a thermal transfer recording apparatus as shown in FIG. 2 can be used. In FIG. 2, 21 is a thermal transfer sheet supply roll, 11 is a thermal transfer sheet, 22 is a take-up roll for winding the used thermal transfer sheet 11, 23 is a thermal head, 24 is a platen roller, 1 is a thermal head 23 and a platen roller. 24 is a thermal transfer image receiving sheet inserted in between.

  A process for forming an image using the thermal transfer recording apparatus shown in FIG. 2 and using, for example, the thermal transfer sheet shown in FIG. 1 will be described. First, the dye layer 13Y containing the yellow dye in FIG. 1 of the thermal transfer sheet and the image receiving layer of the thermal transfer image receiving sheet are overlapped, and the yellow dye in the dye layer 13Y is transferred to the image receiving sheet according to the image data by applying heat from the thermal head 23. A yellow image is then formed, and then the magenta dye is transferred imagewise in the same manner from the dye layer 13M containing the magenta dye on the yellow image, and then the cyan dye is contained on the transferred image. In the same manner, the cyan dye is transferred in an image-like manner from the dye layer 13C to be transferred, and finally, the protective transfer layer unit 14 including the transferable protective transfer layer is thermally transferred from the thermal transfer sheet to the entire surface of the image to complete the image formation. To do.

  In the thermal transfer recording apparatus used in the present invention, it is preferable that glossy tone and matte tone control can be selected in the same apparatus because a printed product having a desired surface property can be obtained with one model. The selection method is not particularly limited. For example, control data corresponding to the glossy tone and matte tone of the present invention is held in the thermal transfer recording apparatus, the control data selected by a simple operation of the operator is read, and the control unit is controlled according to the data. Alternatively, when a personal computer is connected to the recording apparatus, the control data may be held on the personal computer side and the selected control data may be sent to the recording apparatus by a simple operation by the operator. In addition, when heating with a heat roller, a material that alters the surface, for example, a release sheet that gives gloss, a sheet with unevenness for matting is applied to the surface of the image receiving layer after image recording. By heating with a heat roller from the back side of the sheet, recording bodies having different surfaces can be obtained.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these. Unless otherwise specified, “%” and “parts” in the examples represent “parts by mass” and “mass%”, respectively.

Example 1
<Preparation of protective layer transfer sheet>
[Protective layer transfer sheet 1]
(Preparation of support A with back coat layer)
A back coat layer coating solution 1 having the following composition is applied to the surface of a 6 μm thick polyethylene terephthalate film (manufactured by Toray Industries, Inc.) by a gravure coating method and dried, followed by heat curing treatment to obtain a dry film thickness of 1 A support A having a back coat layer of 0.0 μm was prepared.

<Preparation of backcoat layer coating solution 1>
Polyvinyl butyral resin (Sekisui Chemical Co., Ltd., ESREC BX-1) 3.5 parts Phosphate ester surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Prisurf A208S)
3.0 parts Phosphate ester surfactant (Phosphanol RD720 manufactured by Toho Chemical Co., Ltd.)
0.3 part polyisocyanate (Dainippon Ink & Chemicals, Barnock D750-45)
19.0 parts Talc (manufactured by Nippon Talc Co., Ltd. Y / X = 0.03) 0.2 parts Methyl ethyl ketone 35.0 parts Toluene 35.0 parts On the support A, a transferable protective layer coating solution 1 having the following composition Was applied and dried so that the dry film thickness was 1.0 μm to prepare a protective layer transfer sheet 1.

<Preparation of transferable protective layer coating solution 1>
Acrylic resin (Dianar DB90, manufactured by Mitsubishi Rayon) 10.0 parts Methyl ethyl ketone 60.0 parts << Preparation of thermal transfer image-receiving sheet >>
[Thermal transfer image-receiving sheet 1]
As a base material, on one side of a synthetic paper having a thickness of 150 μm (manufactured by Oji Oil Synthetic Paper Co., Ltd., Yupo FPG-150), an image-receiving layer coating solution 1 having the following composition is dried by a wire bar coating method. Was applied so that the solid content of the resin became 4 g / m ^2, and dried at 110 ° C. for 30 seconds to obtain a thermal transfer image-receiving sheet 1.

<Preparation of image-receiving layer coating solution 1>
Polyvinyl butyral resin (Sekisui Chemical Co., Ltd., ESREC BX-1) 7.5 parts Release agent (Shin-Etsu Chemical Co., Ltd., KF410, methylstyryl-modified silicone oil)
0.5 parts methyl ethyl ketone (MEK) 80.0 parts butyl acetate 10.0 parts [thermal transfer image receiving sheet 2]
As a base material, on the one side of a synthetic paper having a thickness of 150 μm (manufactured by Oji Oil Synthetic Paper Co., Ltd., Yupo FPG-150), an image-receiving layer coating liquid 2 having the following composition is dried by a wire bar coating method. After coating so that the solid content amount of the toner was 4 g / m ² , it was dried at 110 ° C. for 30 seconds to obtain a thermal transfer image-receiving sheet 2.

<Preparation of image-receiving layer coating solution 2>
Polyvinyl butyral resin (Sekisui Chemical Co., Ltd. ESREC BX-1) 4.5 parts Metal ion-containing compound (MS-1) 3.0 parts Mold release agent (Shin-Etsu Chemical Co., Ltd., KF410, methylstyryl-modified silicone oil)
0.5 parts methyl ethyl ketone 80.0 parts by mass butyl acetate 10.0 parts by mass MS-1: Ni ²⁺ [C ₇ H ₁₅ COC (COOCH ₃ ) ═C (CH ₃ ) O ⁻ ] ₂
<Preparation of thermal transfer ink sheet>
[Thermal transfer ink sheets 1 to 25]
(Coating back coat layer)
The protective layer transfer sheet has a thickness of 6 μm and a surface of the polyethylene terephthalate film (Mitsubishi Chemical Polyester Film Co., Ltd., K-203E-6F) that has been subjected to easy adhesion treatment on the opposite side to the easy adhesion treatment surface. A thermal transfer ink sheet having a backcoat layer with a dry film thickness of 1.0 μm is applied and dried by a gravure coating method using the same backcoat layer coating solution 1 used for the production of the above, followed by heat curing treatment. Support B was prepared.

(Formation of ink layer)
A coating liquid having the composition shown in Table 1 below is applied to the surface of the support B prepared on the side opposite to the surface provided with the backcoat layer by a gravure coating method and dried to prepare thermal transfer ink sheets 1 to 25. did. The thickness of the ink layer after drying was 0.8 μm.

  Details of the abbreviation compounds described in Table 1 are shown in Tables 2 and 3.

<Image formation>
A thermal transfer recording apparatus equipped with a thermal head having a resistor shape of square (main scanning direction length 80 μm × sub scanning direction length 120 μm) and 300 dpi (dpi represents the number of dots per 2.54 cm) is shown in the table below. In combination, the image receiving layer portion of the thermal transfer image receiving sheet and the ink layer of the thermal transfer ink sheet are set in an overlapping manner, and sequentially in the applied energy range of 5 to 80 mJ / mm ² while being pressed by the thermal head and the platen roll. The step pattern to be increased is a feed rate of 10 msec / line, a feed length per line of 85 μm, heated from the back side of the ink layer, and each dye is transferred onto the image receiving layer of the thermal transfer image receiving sheet to transfer the image. Formed.

Next, using the same thermal transfer recording apparatus used for image formation, the image-receiving sheet on which the image was formed and the produced protective layer transfer sheet were superposed and pressed with a thermal head and a platen roll, and 60 mJ / mm Image formations 1 to 25 were produced by heating from the back side of the protective layer transfer sheet at an applied energy of ² and a feed rate of 10 msec / line to transfer the protective layer to the entire surface of the image of the image receiving sheet.

<< Evaluation of image formation >>
The following evaluations were performed on each image produced as described above.

(Evaluation of concentration)
The reflection optical density of the maximum density portion of the produced image pattern was measured using a densitometer (X-rite 310), and the density was evaluated according to the following criteria.

◎: Concentration is 2.2 or more ○: Concentration is 2.1 or more and less than 2.2 △: Concentration is 1.9 or more and less than 2.1 ×: Concentration is less than 1.9 (fogging evaluation)
The prepared image formed product was stored in a constant temperature and humidity chamber of 60 °, 80% RH for one month, and then the reflection optical density (blue filter density) of the white background portion of the image was measured using a densitometer (X-rite 310). The fog was evaluated according to the following criteria by measuring and comparing with the concentration before storage treatment for 1 month in a constant temperature and humidity chamber of 60 ° and 80% RH.

◎: White background density increase less than 0.01 ○: White background density increase is 0.01 or more and less than 0.03 Δ: White background density increase is 0.03 or more and less than 0.1 ×: White background part Concentration increase of 0.1 or more (Evaluation of sensitivity)
The applied energy (E) giving a reflection density of 1.0 was measured with an optical densitometer, and the sensitivity was evaluated according to the following criteria.

A: E ≦ 4.8 × 10 ⁻³ J
○: 4.8 × 10 ⁻³ J <E ≦ 5.2 × 10 ⁻³ J
Δ: 5.2 × 10 ⁻³ J <E ≦ 5.6 × 10 ⁻³ J
×: E> 5.6 × 10 ⁻³ J
Table 4 shows the results obtained as described above.

  As is apparent from the results in Table 4, it can be seen that the thermal transfer ink sheet of the present invention has little fogging with time and an image having excellent density and sensitivity.

It is a perspective view which shows an example of the thermal transfer sheet which concerns on this invention. It is a schematic diagram showing an example of a thermal transfer recording apparatus used in the image forming method of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermal transfer image-receiving sheet 11 Thermal transfer sheet 12 Base material sheet 13Y, 13M, 13C Dye layer 14 Protective transfer layer unit 15 Non-transferable peeling layer 16 Protective transfer layer 17 Adhesive layer 21 Roll of supply of thermal transfer sheet 22 Used thermal transfer sheet Winding roll for winding 23 Thermal head 24 Platen roller

Claims (5)

A thermal transfer ink sheet having an ink layer containing at least a heat diffusible dye on a support, wherein the ink layer contains a surfactant having an HLB of 10 or more. The thermal transfer ink sheet according to claim 1, wherein the surfactant has an HLB of 12 or more. The thermal transfer ink sheet according to claim 1 or 2, wherein an addition amount of the surfactant in the ink layer is 1% by mass or more. The thermal transfer ink sheet according to any one of claims 1 to 3, wherein the thermal diffusible dye is capable of forming a chelate complex with a metal ion-containing compound. An image forming method using the thermal transfer ink sheet and the thermal transfer image receiving sheet according to claim 1.

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