JP2011073375A - Thermal transfer sheet, image forming method, and printed matter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal transfer sheet capable of attaining an image of excellent light-resistance, high sensitivity and high density, and an image forming method and a printed matter using the sheet. <P>SOLUTION: This thermal transfer sheet includes at least a yellow dye layer and a cyan dye layer on a base material sheet, a yellow dye comprises one kind selected from the group comprising compounds shown by general formula (1) and the like, and a cyan dye comprises anthraquinone compounds or the like, the thermal transfer sheet is used combinedly with an image reception sheet, a dye reception layer contains a styrene-acrylic copolymer, a cooling gelling agent, and a mold release agent, and a molar ratio of a styrene unit to an acrylic compound unit is 60-80/40-20 in the styrene-acrylic copolymer. In the general formula (1), R<SP>1</SP>represents hydrogen atom, a substituted or nonsubstituted alkyl group, or an alkoxy group, R<SP>2</SP>represents an alkoxycarbonyl group, an alkyl amino carbonyl group, an alkoxy group, an alkoxyalkoxy group, an alkyl group, a cycloalkyl group, or a heterocyclic group, and X represents hydrogen atom, or a halogen atom. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a thermal transfer sheet, an image forming method, and a printed matter.

As a method of forming an image using thermal transfer, a thermal transfer sheet in which a thermal diffusion dye (sublimation dye) as a recording material is carried on a base sheet such as a plastic film, and another base such as paper or plastic film A thermal diffusion transfer system (sublimation thermal transfer system) is known in which a thermal transfer image receiving sheet provided with a dye receiving layer on a sheet is superposed on each other to form a full color image.
In the sublimation type thermal transfer system, generally, full color expression is performed by sequentially superimposing three primary colors (three colors of yellow, magenta, and cyan; black may be added if necessary) and sequentially printing gradations.

The image obtained by such a sublimation type thermal transfer method can form a high quality image similar to a silver salt photograph, and accordingly, light, heat, humidity, etc. are maintained while maintaining a high image density. There is an increasing demand for preventing image quality deterioration due to these factors.

Development of novel dyes, image forming methods, and the like has been conventionally performed in order to improve image storage stability of image objects.
For example, Patent Document 1 discloses an image forming method using a heat-sensitive transfer sheet having a dye layer containing a specific dye and a heat-sensitive transfer image-receiving sheet having a receiving layer and a specific heat insulating layer.
However, in such an image forming method, depending on the relationship between the dye of the heat-sensitive transfer sheet and the heat-sensitive transfer image-receiving sheet, both image storability and print density are not always satisfactory, and further improvements can be made. It was sought after.

JP 2008-87298 A

An object of the present invention is to provide a thermal transfer sheet that is excellent in light resistance and capable of realizing a high-sensitivity and high-density image, an image forming method using the sheet, and a printed matter.

The present invention is a thermal transfer sheet having at least a yellow dye layer and a cyan dye layer on a substrate sheet, wherein the dye contained in the yellow dye layer is a compound represented by the general formula (1), a general formula The dye represented by (2) and at least one selected from the group consisting of the compound represented by formula (3), and the dye contained in the cyan dye layer is represented by formula (4) A thermal transfer image-receiving sheet comprising at least a dye-receiving layer and a porous layer on another substrate sheet, the thermal transfer sheet comprising a compound represented by formula (5) and / or a compound represented by the general formula (5): Used in combination to form an image, the dye-receiving layer contains a styrene-acrylic copolymer (a), a cooling gelling agent (b) and a release agent (c), and the styrene-acrylic Of the copolymer (a) The molar ratio of styrene unit and an acrylic compound unit ([styrene unit] / [acrylic compound]) is a thermal transfer sheet, which is a 60-80 / 40-20.

In the general formula (1), R ¹ represents a hydrogen atom, a substituted or unsubstituted alkyl group, or an alkoxy group, and R ² represents an alkoxycarbonyl group, an alkylaminocarbonyl group, an alkoxy group, an alkoxyalkoxy group, An alkyl group, a cycloalkyl group, or a heterocyclic group is represented, and X represents a hydrogen atom or a halogen atom. ;

In the general formula (2), R ³ and R ⁴ are the same or different functional groups, and are a substituted or unsubstituted lower alkyl group, a substituted or unsubstituted lower alkenyl group, or a substituted or unsubstituted aryl. R ⁵ and R ⁶ are the same or different functional groups and represent a substituted or unsubstituted lower alkyl group. ;

In the general formula (3), R ⁷ and R ⁸ are the same or different functional groups, and are a hydrogen atom, a substituted or unsubstituted alkyl group, an allyl group, a substituted or unsubstituted aryl group, or cycloalkyl. R ⁹ represents a hydrogen atom, a substituted or unsubstituted alkyl group, an NR ¹¹ R ¹² group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkoxycarbonyl group, a substituted or unsubstituted aryl group, Or, it represents a C (O 2) NR ¹³ R ¹⁴ group, R ¹⁰ represents a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, and the above R ¹¹ , R ¹² , R ¹³ and R ¹⁴ Each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group;

In the general formulas (4) and (5), R ¹⁵ and R ¹⁶ are the same or different functional groups, and are substituted or unsubstituted alkyl groups, substituted or unsubstituted cycloalkyl groups, or substituted or non-substituted groups. R ¹⁷ represents a substituted or unsubstituted alkoxycarbonyl group, a substituted or unsubstituted alkylaminocarbonyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkyl group, substituted or unsubstituted R ¹⁸ represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylcarbonylamino group, a substituted or unsubstituted cycloalkyl group, a heterocyclic group, or a halogen atom. Alkylsulfonylamino group, substituted or unsubstituted alkylaminocarbonyl group, Represents a substituted or unsubstituted alkylaminosulfonyl group or a halogen atom; R ¹⁹ represents CONHR ²¹ , SO ₂ NHR ²¹ , NHCOR ²² , NHSO ₂ R ^22, or a halogen atom, and R ²⁰ represents a substituted or unsubstituted atom. X represents a halogen atom, and R ²¹ represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted group. R ²² represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, or a substituted group. Alternatively, it represents an unsubstituted aromatic heterocyclic group.

In the thermal transfer sheet, the dye contained in the yellow dye layer is represented by the compound represented by the formula (1-1), the compound represented by the formula (2-1), and the formula (3-1). And the dye contained in the cyan dye layer is represented by the compound represented by the formula (4-1) and / or the formula (5-1). It preferably consists of a compound.

The present invention also includes a thermal transfer sheet having at least a yellow dye layer and a cyan dye layer on a base sheet, and a thermal transfer image receiving sheet having at least a dye receiving layer and a porous layer on another base sheet. An image forming method using an image forming method, wherein the dye contained in the yellow dye layer includes a compound represented by the general formula (1), a compound represented by the general formula (2), and a general formula The dye which consists of at least 1 sort (s) selected from the group which consists of a compound represented by (3), and is contained in the said cyan dye layer is a compound represented by General formula (4), and / or General formula (5) The dye-receiving layer of the thermal transfer image-receiving sheet contains a styrene-acrylic copolymer (a), a cooling gelling agent (b) and a release agent (c), and the styrene -Of the acrylic copolymer (a) The molar ratio of styrene unit and an acrylic compound unit ([styrene unit] / [acrylic compound]) is, is also an image forming method characterized in that it is a 60-80 / 40-20.

In the general formula (1), R ¹ represents a hydrogen atom, a substituted or unsubstituted alkyl group, or an alkoxy group, and R ² represents an alkoxycarbonyl group, an alkylaminocarbonyl group, an alkoxy group, an alkoxyalkoxy group, Represents an alkyl group, a cycloalkyl group or a heterocyclic group, and X represents a hydrogen atom or a halogen atom. ;

In the general formula (2), R ³ and R ⁴ are the same or different functional groups, and are a substituted or unsubstituted lower alkyl group, a substituted or unsubstituted lower alkenyl group, or a substituted or unsubstituted aryl. R ⁵ and R ⁶ are the same or different functional groups and represent a substituted or unsubstituted lower alkyl group. ;

In the general formula (3), R ⁷ and R ⁸ are the same or different functional groups, and are a hydrogen atom, a substituted or unsubstituted alkyl group, an allyl group, a substituted or unsubstituted aryl group, or cycloalkyl. R ⁹ represents a hydrogen atom, a substituted or unsubstituted alkyl group, an NR ¹¹ R ¹² group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkoxycarbonyl group, a substituted or unsubstituted aryl group, Or, it represents a C (O 2) NR ¹³ R ¹⁴ group, R ¹⁰ represents a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, and the above R ¹¹ , R ¹² , R ¹³ and R ¹⁴ Each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. ;

In the general formulas (4) and (5), R ¹⁵ and R ¹⁶ are the same or different functional groups, and are substituted or unsubstituted alkyl groups, substituted or unsubstituted cycloalkyl groups, or substituted or non-substituted groups. R ¹⁷ represents a substituted or unsubstituted alkoxycarbonyl group, a substituted or unsubstituted alkylaminocarbonyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkyl group, substituted or unsubstituted R ¹⁸ represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylcarbonylamino group, a substituted or unsubstituted cycloalkyl group, a heterocyclic group, or a halogen atom. Alkylsulfonylamino group, substituted or unsubstituted alkylaminocarbonyl group, Represents a substituted or unsubstituted alkylaminosulfonyl group or a halogen atom; R ¹⁹ represents CONHR ²¹ , SO ₂ NHR ²¹ , NHCOR ²² , NHSO ₂ R ^22, or a halogen atom, and R ²⁰ represents a substituted or unsubstituted atom. X represents a halogen atom, and R ²¹ represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted group. R ²² represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, or a substituted group. Alternatively, it represents an unsubstituted aromatic heterocyclic group.

In the image forming method, the dye contained in the yellow dye layer is represented by the compound represented by the formula (1-1), the compound represented by the formula (2-1), and the formula (3-1). And the dye contained in the cyan dye layer is represented by the compound represented by formula (4-1) and / or the formula (5-1). It is preferable to consist of a compound.

The present invention is also a printed matter obtained by the image forming method described above.
The present invention is described in detail below.

In recent years, as materials for thermal transfer sheets and thermal transfer image-receiving sheets used in image forming methods in the sublimation thermal transfer system, conversion to water-based materials has been attempted in order to further reduce the burden on the environment. The inventors of the present invention have previously developed a thermal transfer image-receiving sheet made of an aqueous material excellent in high sensitivity, light resistance and releasability of a printed material.
On the other hand, a wide variety of sublimation dyes used for thermal transfer sheets are known. However, depending on the dye contained in the dye layer of the thermal transfer sheet, an image having desired light resistance, sensitivity, and density could not be obtained even in combination with such a thermal transfer image-receiving sheet made of an aqueous material.

As a result of intensive studies, the present inventors have combined a thermal transfer image-receiving sheet having a specific dye-receiving layer made of such an aqueous material with a thermal transfer sheet having a yellow dye layer containing a specific dye and a cyan dye layer. By using this method and forming an image by the sublimation thermal transfer method, it is possible to obtain a highly sensitive, high-density green image object that has extremely excellent light resistance compared to conventional image objects. For the first time, and completed the present invention.

Hereinafter, the thermal transfer sheet of the present invention will be described.
(Thermal transfer sheet)
The thermal transfer sheet of the present invention has at least a yellow dye layer and a cyan dye layer on a base sheet.
The dye contained in the yellow dye layer is a group consisting of a compound represented by the general formula (1), a compound represented by the general formula (2), and a compound represented by the general formula (3). It consists of at least one selected from more. By forming a thermal transfer sheet having such a yellow dye layer containing a specific dye and a cyan dye layer containing a specific dye described later, and performing image formation by thermal transfer in combination with a specific thermal transfer image receiving sheet described later, A green image with excellent light resistance, high sensitivity, and high density can be obtained.

Among them, the dye contained in the yellow dye layer is a compound represented by the above formula (1-1) in that a green image with high sensitivity and higher density and excellent light resistance can be obtained. It is preferably composed of at least one selected from the group consisting of the compound represented by the above formula (2-1) and the compound represented by the above formula (3-1).
Furthermore, the dye contained in the yellow dye layer is composed of a compound represented by the above formula (2-1) and a compound represented by the above formula (3-1), or the above formula (1-1). ) And a compound represented by the above formula (3-1) are more preferable.

The dye content in the yellow dye layer is preferably 35 to 70% by mass. If it is less than 35% by mass, the print density may be insufficient. When it exceeds 70 mass%, when the thermal transfer sheet of the present invention is placed under high temperature and high humidity, the dye may be precipitated. The content of the dye is more preferably 50 to 70% by mass. In addition, content of the said dye is those total amounts, when the said dye is contained 2 or more types.

In the yellow dye layer, when the compound of the above formula (2-1) and the compound of the above formula (3-1) are used in combination as the dye, the content ratio thereof [compound of formula (2-1) / formula The compound of (3-1)] is preferably 4/6 to 6/4 in terms of solid content mass ratio.
Moreover, when using together the compound of said Formula (1-1), and the compound of said Formula (3-1), these content ratio [The compound of Formula (1-1) / The compound of Formula (3-1) ] Is preferably 4/6 to 6/4 in solid content ratio.
By setting the content ratio in the above range, it is possible to obtain a green image having excellent light resistance, higher sensitivity, and higher density.

The dye contained in the cyan dye layer comprises a compound represented by the general formula (4) and / or a compound represented by the general formula (5). By forming a thermal transfer sheet having such a cyan dye layer containing a specific dye and the above-described yellow dye layer, image formation by thermal transfer in combination with a thermal transfer image receiving sheet described later is excellent in light resistance and sensitivity. And a green image with a high density can be obtained.

Among them, the dye contained in the cyan dye layer is a compound represented by the above formula (4-1) in that a green image with high sensitivity and higher density and excellent light resistance can be obtained. And / or preferably composed of a compound represented by the above formula (5-1), more preferably composed of a compound of the above formula (4-1) and a compound of the above formula (5-1).

The content of the dye in the cyan dye layer is preferably 35 to 70% by mass. If it is less than 35% by mass, the print density may be insufficient. When it exceeds 70 mass%, when the thermal transfer sheet of the present invention is placed under high temperature and high humidity, the dye may be precipitated. The content of the dye is more preferably 50 to 70% by mass. In addition, content of the said dye is those total amounts, when the said dye is contained 2 or more types.

In the cyan dye layer, when the compound represented by the above formula (4-1) and the compound represented by the above formula (5-1) are used in combination, the content ratio [formula (4- The compound of 1) / the compound of formula (5-1)] is preferably 4/6 to 6/4 in terms of solid content mass ratio.
By setting the content ratio in the above range, it is possible to obtain a green image having excellent light resistance, higher sensitivity, and higher density.

The yellow dye layer and the cyan dye layer contain a binder resin.
As the binder resin for these dye layers, generally, those having heat resistance and moderate affinity with the dye can be used.
Examples of the binder resin include cellulose resins such as ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, cellulose butyrate; polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetoacetal, polyvinyl pyrrolidone. Vinyl resins such as poly (meth) acrylates, poly (meth) acrylamides and the like; polyurethane resins; polyamide resins; polyester resins;
Among these, a cellulose resin, a vinyl resin, an acrylic resin, a polyurethane resin, and a polyester resin are preferable, and a vinyl resin is more preferable in terms of excellent heat resistance and dye transfer.

The yellow dye layer and the cyan dye layer may use additives such as a release agent, inorganic fine particles, and organic fine particles, if desired. As these additives, known ones can be used. Moreover, these dye layers may contain dyes other than the dye mentioned above in the range which does not inhibit the effect of this invention.

The yellow dye layer and the cyan dye layer are dye layer-forming coatings obtained by dissolving or dispersing the above-described dye and binder resin in an appropriate organic solvent or water, together with additives to be added as necessary. It is good to form by a well-known method using a liquid. The yellow dye layer and the cyan dye layer are preferably formed in the surface order.

The base sheet of the thermal transfer sheet is not particularly limited as long as it has a certain degree of heat resistance and strength. For example, a polyethylene terephthalate film, a 1,4-polycyclohexylenedimethylene terephthalate film, a polyethylene naphthalate film, Polyphenylene sulfide film, polystyrene film, polypropylene film, polysulfone film, aramid film, polycarbonate film, polyvinyl alcohol film, cellophane, cellulose derivatives such as cellulose acetate, polyethylene film, polyvinyl chloride film, nylon film, polyimide film, ionomer film, etc. Resin film; paper such as condenser paper, paraffin paper, synthetic paper; nonwoven fabric; composite of paper or nonwoven fabric and resin; It is below.
The substrate sheet generally has a thickness of preferably about 0.5 to 50 μm, and more preferably about 1.5 to 10 μm.

The base sheet may be subjected to various known surface treatments in order to improve adhesion with adjacent layers. Among these surface treatments, corona treatment or plasma treatment is preferred because of its low cost. Moreover, you may form an undercoat layer (primer layer) in the one surface or both surfaces as needed.

The thermal transfer sheet may have other layers such as a transfer protective layer, a heat-resistant slip layer, and an undercoat layer in addition to the dye layer and the base sheet described above. These layer configurations may be generally known layer configurations.
The heat-resistant slipping layer is a layer that plays a role in preventing problems caused by poor running of the thermal head during thermal transfer. The heat-resistant slip layer is usually located on a surface side different from the surface side of the substrate sheet on which the dye layer is located.
The heat resistant slipping layer may be formed by a known method using a known material.
Examples of the transfer protective layer include those composed of an adhesive layer, a release layer, and a release layer. By forming the transfer protective layer in the surface order with the above-described dye layer, the protective layer for protecting the image surface can be transferred after image formation.
The configuration and preparation of the transfer protective layer are not particularly limited, and can be selected from conventionally known techniques depending on the characteristics of the base material sheet, the dye layer, and the like to be used.
The undercoat layer is not particularly limited, and a composition that improves the adhesion between the substrate and the dye layer and the transfer efficiency of the dye can be appropriately selected and provided.

(Thermal transfer image receiving sheet)
The thermal transfer sheet of the present invention is used in combination with a specific thermal transfer image receiving sheet to form an image.
The thermal transfer image-receiving sheet used in combination with the thermal transfer sheet of the present invention has at least a dye receiving layer and a porous layer on a base sheet, and the dye receiving layer has a specific copolymerization ratio. It contains a copolymer (a), a cooling gelling agent (b) and a release agent (c). For this reason, it can be set as the thermal transfer image receiving sheet which consists of a water-system material excellent in the high sensitivity of a printed matter, light resistance, and mold release property.
When the thermal transfer sheet of the present invention is formed by thermal transfer in combination with a specific thermal transfer image-receiving sheet made of such an aqueous material, it is excellent in light resistance and forms a green image with high sensitivity and high density. Can do.

The dye receiving layer is a layer that receives the above-described dye from the thermal transfer sheet when heated. The dye-receiving layer contains at least a styrene-acrylic copolymer (a) a cooling gelling agent (b) and a mold release (c).

The styrene-acrylic copolymer (a) is not particularly limited as long as it is a copolymer formed from styrene units and acrylic compound units, and these essential monomers in addition to styrene and acrylic compounds. A monomer copolymerizable with a small amount may also be used.
In the present specification, “acrylic compound” means (meth) acrylic acid and / or an alkyl ester thereof.
Examples of the acrylic compound include acrylic acid; acrylic acid salts such as calcium acrylate, zinc acrylate, magnesium acrylate, and aluminum acrylate; methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and 2-ethoxy. Acrylic acid esters such as ethyl acrylate, 2-hydroxyethyl acrylate, lauryl acrylate, n-stearyl acrylate, tetrahydrofurfuryl acrylate, trimethylolpropane triacrylate; methacrylic acid; methyl methacrylate, ethyl methacrylate, t-butyl methacrylate, Tridecyl methacrylate, cyclohexyl methacrylate, triethylene glycol dimethacrylate, 1,3-butylene dimethacrylate, trimeta Methacrylic acid esters such as acrylic acid trimethylol propane, and the like. Among these, when a long-chain acrylic compound is used as a monomer, the light resistance is remarkably improved.

The molar ratio of styrene units to acrylic compound units ([styrene unit] / [acrylic compound]) in the styrene-acrylic copolymer (a) is preferably 60 to 80/40 to 20. By setting the styrene unit in the styrene-acrylic copolymer (a) to 60 mol% or more, the glass transition temperature (Tg) becomes relatively high. Therefore, the dye receiving layer containing such a copolymer is In addition to excellent heat resistance, light resistance can be improved. If the styrene unit exceeds 80 mol%, Tg increases and the heat resistance is excellent, but there is a possibility that the dye dyeability is lowered and the image density is lowered.
The styrene-acrylic copolymer (a) may be a random copolymer or a block copolymer.

The styrene-acrylic copolymer (a) preferably has a number average molecular weight (polystyrene conversion) of 150,000 or more. If the number average molecular weight is less than 150,000, the releasability may be reduced during thermal transfer. The upper limit of the number average molecular weight (in terms of polystyrene) of the styrene-acrylic copolymer (a) is practically about 250,000 from the polymerization conditions.

The styrene-acrylic copolymer (a) is preferably contained in the dye-receiving layer in an amount of 50 to 95% by weight, more preferably 70 to 95% by weight, and still more preferably 80 to 90% by weight. In the present invention, as the resin for forming the dye receiving layer, only one kind may be used, or two or more kinds having different average molecular weights may be used.

The minimum temperature (minimum film forming temperature (MFT)) for the styrene-acrylic copolymer (a) to form a smooth and transparent continuous coating film is preferably 30 to 90 ° C, more preferably 40 to 80 ° C, 45-75 degreeC is still more preferable. A film-forming aid can be added to control the minimum film-forming temperature. In the present invention, the minimum film forming temperature of the styrene-acrylic copolymer (a) is preferably higher than the glass transition temperature.

The styrene-acrylic copolymer (a) can be produced by a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, a dispersion polymerization method, an ionic polymerization method, or the like. Among these, since the styrene-acrylic copolymer (a) is preferably added as a latex from the viewpoint that the forming coating solution for forming the dye-receiving layer is formed in an aqueous solvent, The emulsion polymerization method obtained as a latex is most preferred.
In the present invention, “aqueous” means that 50% by mass or more of the coating liquid is water or an organic solvent that can be mixed with water uniformly (for example, alcohols such as methanol, ethanol, isopropanol, n-propanol; ethylene glycol) And glycols such as diethylene glycol and glycerine; esters such as ethyl acetate and propyl acetate; ketones such as acetone and methyl ethyl ketone; amides such as N, N-dimethylformamide and the like].

In the emulsion polymerization method, water or a mixed solution of water and the organic solvent that can be uniformly mixed with water is used as a dispersion medium, and for example, 10 to 150 parts by mass of styrene and the acrylic system with respect to 100 parts of the dispersion medium. This is a polymerization method in which a compound, a polymerization emulsifier, a polymerization initiator and the like are used and polymerized with stirring at a temperature of 20 to 100 ° C. for about 1 to 20 hours.
As the polymerization initiator, radical agents such as inorganic peroxides and azo compounds can be used. The amount of the polymerization initiator added is preferably 0.2 to 3.0 parts by mass with respect to 100 parts by mass of the monomer.
As the polymerization emulsifier, an anionic surfactant, a cationic surfactant, an amphoteric surfactant and the like can be used. The addition amount of the polymerization emulsifier is preferably 0.2 to 10.0 parts by mass with respect to 100 parts by mass of the monomer. In the emulsion polymerization method, a chain transfer agent or a chelating agent may be used.

The cooling gelling agent (b) has a property of gelling when cooled, and examples thereof include gelatin, polyvinyl alcohol, agar, κ-carrageenan, λ-carrageenan, ι-carrageenan, and pectin. be able to. Of these, gelatin is preferable. The cooling gelling agent (b) preferably has a viscosity at 15 ° C. in a state dissolved in water of 3 times or more, particularly 5 times or more, more preferably 10 times or more of the viscosity at 80 ° C. .

Here, the gelatin is composed of a peptide chain obtained by denaturing collagen having a triple helix structure. The gelatin partially recovers the triple helix structure by being cooled, and the recovered triple helix structure. By forming a three-dimensional network starting from the helix structure, it exhibits cooling gelation characteristics. As a raw material for gelatin, gelatin obtained from collagen made from pork skin, pork bone, cow skin, cow bone, fish scale, fish skin and the like can be used. Further, the type of gelatin is not particularly limited, and lime-processed gelatin, acid-processed gelatin, and so-called derivative gelatin in which the amino groups of gelatin are completely or partially blocked can also be used.

The derivative gelatin is preferably a derivative gelatin in which the amino group of gelatin is blocked, and includes those obtained by isocyanate addition, acylation, or deamination. Specifically, gelatin obtained by adding gelatin and phenyl isocyanate, alkyl isocyanate or the like, or a product obtained by reacting acid anhydride such as phthalic anhydride or acid chloride such as phthalic chloride is preferable. The ratio of amino group blocking in gelatin is 70% or more, preferably 80% or more, more preferably 90% or more of the amino group. The film using gelatin may be hardened with a hardener in a range satisfying water solubility. In the present invention, gelatin having a molecular weight of 10,000 to 1,000,000 is preferably used. The gelatin used in the present invention may contain anions such as Cl ⁻ and SO ₄ ²⁻ , and may contain cations such as Fe ²⁺ , Ca ²⁺ , Mg ²⁺ , Sn ²⁺ and Zn ^2+. . It is preferable to add gelatin dissolved in water.

The gelatin may be a commercially available one. For example, gelatin manufactured by Nitta Gelatin (trade names: MJ, R, APH-200, etc.), gelatin manufactured by Nippi (trade names: DP, DG, DB, MAX-F, etc.), Gelatin (trade name: AU, AU-P, AU-G, AU-S, etc.) manufactured by Zerais Co., Ltd., and the like.

The content of the cooling gelling agent (b) is the desired surface tension and viscosity characteristics of the dye-receiving layer-forming coating solution used for forming the dye-receiving layer when the thermal transfer image-receiving sheet is produced. However, it is preferably 2 to 30% by mass in the dye-receiving layer. When the content is less than 2% by mass, for example, when the dye-receiving layer-forming coating liquid is applied and dried on the substrate sheet, unevenness may easily occur. On the other hand, when it exceeds 30% by mass, the dyeing property of the dye may be lowered during image formation, and the image density may be lowered. The content is more preferably 2 to 25% by mass, still more preferably 2 to 20% by mass.

Examples of the release agent (c) include conventionally known release agents, for example, solid waxes such as silicone oil, polyethylene wax, amide wax, and Teflon (registered trademark), fluorine-based and phosphate-based surfactants. And silicone. Of these, modified silicone oil is preferred. The said mold release agent may be used independently and may use 2 or more types together.

The content of the release agent (c) is preferably 2 to 30% by mass in the dye receiving layer. When the content of the release agent is less than 2% by mass, there is a possibility that the thermal transfer sheet and the thermal transfer image receiving sheet are fused and cannot be printed normally when a printed product is produced using the thermal transfer image receiving sheet. On the other hand, if it exceeds 30% by mass, the print sensitivity may be lowered when a printed product is produced. The content of the release agent is more preferably 2 to 25% by mass, and further preferably 2 to 20% by mass.

In addition to the above-described components, the dye-receiving layer may include a surfactant, an antioxidant, an ultraviolet absorber, a light stabilizer, a filler, a pigment, an antistatic agent, a plasticizer, a hot-melt material, etc. The additive may be included. These can use a well-known thing.
The dye-receiving layer may be formed by a known method using a dye-receiving layer-forming coating solution obtained by dispersing the above-described components in water or an organic solvent that can be uniformly mixed with water. .

The thickness of the dye-receiving layer is not particularly limited as long as the desired image density can be expressed, but is preferably in the range of 0.5 to 20 μm, more preferably 1 to 20 μm, 1-15 micrometers is still more preferable.

The thermal transfer image receiving sheet has a porous layer.
The porous layer is a layer having a heat insulating property and cushioning property that suppresses heat applied from the thermal head to the dye receiving layer from being transferred to the base sheet side when an image is formed by thermal transfer.
The porous layer preferably contains hollow particles (d) and a cooling gelling agent (e).

The hollow particles are not particularly limited as long as they can impart desired heat insulating properties and cushioning properties to the porous layer, and include, for example, expanded particles or non-expanded particles, independent expanded particles or continuous expanded particles, and resins. Organic hollow particles, inorganic hollow particles composed of glass and the like, crosslinked hollow particles, and the like.

Examples of the resin constituting the hollow particles (d) include styrene resins such as crosslinked styrene-acrylic resins, (meth) acrylic resins such as acrylonitrile-acrylic resins, phenolic resins, fluorine resins, and polyamide resins. , Polyimide resin, polycarbonate resin, polyether resin and the like.

The average particle diameter of the hollow particles (d) is not particularly limited as long as desired heat insulating properties and cushioning properties can be imparted to the porous layer according to the type of resin constituting the hollow particles (d). Although it is not a thing, 0.1-15 micrometers is preferable normally and 0.1-10 micrometers is more preferable. If the average particle size is too small, the amount of hollow particles (d) used may increase and the cost may increase. If the average particle size is too large, it may be difficult to form a smooth porous layer.
The hollow particles preferably have a hollow ratio of about 30 to 80%. Further, two or more hollow ratios may be mixed and used.

The content of the hollow particles (d) in the porous layer is not particularly limited as long as a porous layer having desired heat insulating properties and cushioning properties can be obtained. For example, 50 to 90% by mass is preferable. 60 to 85% by mass is more preferable.
When there is too little content of the said hollow particle (d), the space | gap in a porous layer will decrease and there exists a possibility that sufficient heat insulation and cushioning properties may not be obtained. On the other hand, when there is too much said content, there exists a possibility that adhesiveness may fall.

Examples of the cooling gelling agent (e) contained in the porous layer include the same cooling gelling agent (b) contained in the dye receiving layer as described above. It may be a combination of two or more.

The porous layer may contain other components as needed in addition to the hollow particles (d) and the cooling gelling agent (e) described above. Examples of the other components include a binder resin, a nonionic silicone surfactant, a curing agent such as an isocyanate compound, a wetting agent, and a dispersant.

The porous layer uses the porous layer coating liquid obtained by mixing and dispersing the hollow particles, the cooling gelling agent, and other components in water or an aqueous solvent as necessary. It may be formed by a known method.

The thickness of the porous layer is preferably 10 to 100 μm, and more preferably 10 to 50 μm. The density of the porous layer, for example, preferably 0.1 to 0.8 g / cm ^3, more preferably 0.2 to 0.7 g / cm ^3.

The porous layer may have a configuration composed of a single layer, or may have a configuration in which a plurality of layers are laminated. The porous layer having a structure in which a plurality of layers are stacked may have a structure in which layers having the same composition are stacked, or a structure in which layers having different compositions are stacked. There may be.

The base sheet of the thermal transfer image-receiving sheet has a function of supporting the porous layer and the dye-receiving layer, and has a desired heat resistance depending on the printing temperature when an image is formed from the thermal transfer sheet by thermal transfer. Although it will not specifically limit if it is provided, Specifically, a resin coat paper, a resin-made film base material, a paper-made base material, etc. can be mentioned, Resin coat paper is especially preferable.

The resin-coated paper is usually one in which a base resin layer is laminated on both sides of a base paper. Examples of the base paper constituting the base paper include natural pulp, synthetic pulp, and pulp paper made from a mixture thereof. Among these, it is preferable to use paper mainly composed of wood pulp. The base paper may be subjected to a conventionally known process such as a calendar process to be described later if necessary.
10-1000 micrometers is preferable and, as for the thickness of the said base paper, 50-300 micrometers is more preferable.

The base paper can be produced by a known method, but a base paper that is calendered is preferable. This is because when a base paper that has been calendered is used for the base paper, the smoothness can be improved and the glossiness of the resulting thermal transfer image-receiving sheet can be enhanced. The resin for forming the base resin layer is preferably a resin having a small neck-in and a good drawdown property. For example, a polyolefin resin, a polystyrene resin, a vinyl resin, a polyester resin, an ionomer Resin, nylon, polyurethane and the like can be mentioned, and a polyolefin resin is preferable in that a film excellent in water resistance, strength, gloss and the like can be obtained.
Examples of the polyolefin resin include high-density polyethylene, medium-density polyethylene, low-density polyethylene, polypropylene, polybutene, and polypentene. Among these, high-density polyethylene, medium-density polyethylene, low-density polyethylene, and polypropylene are preferable, and polypropylene is particularly preferable. Is preferred.

The base resin layer may be a film or sheet obtained by mixing one or more of the resins, or a film or sheet formed by adding a pigment, a filler or the like to the resin. It may be. Further, the resin may be one obtained by blending an additive such as a modifier to improve adhesiveness. Examples of the modifier include olefin copolymers such as trade name: Tuffmer manufactured by Mitsui Chemicals.
The resin-coated paper can be produced by a known laminating method such as dry lamination, wet lamination, or extrusion. Each of the above layers can be appropriately subjected to primer treatment or corona discharge treatment for the purpose of improving interlayer adhesion.
10-1000 micrometers is preferable and, as for the thickness of the said resin coat paper, 50-300 micrometers is more preferable.

Examples of the resin film substrate include polyester, polyacrylate, polycarbonate, polyurethane, polyimide, polyetherimide, cellulose derivative, polyethylene, ethylene-vinyl acetate copolymer, polypropylene, polystyrene, acrylic, polyvinyl chloride, poly Vinylidene chloride, polyvinyl alcohol, polyvinyl butyral, nylon, polyether ether ketone, polysulfone, polyether sulfone, tetrafluoroethylene, perfluoroalkyl vinyl ether, polyvinyl fluoride, tetrafluoroethylene-ethylene, tetrafluoroethylene-hexafluoropropylene, Examples thereof include polychlorotrifluoroethylene and polyvinylidene fluoride. Among these, in the present invention, polyethylene terephthalate and polypropylene resin can be preferably used.
The thickness of the resin film substrate is preferably 20 to 100 μm, more preferably 25 to 60 μm, and still more preferably 30 to 50 μm.

Examples of the paper substrate include condenser paper, glassine paper, sulfuric acid paper, or high-size paper, synthetic paper (polyolefin-based, polystyrene-based), high-quality paper, art paper, coated paper, cast-coated paper, Examples include wallpaper, backing paper, synthetic resin or emulsion-impregnated paper, synthetic rubber latex-impregnated paper, synthetic resin-added paper, paperboard, and cellulose fiber paper.
Although it does not specifically limit as thickness of the said paper-made base material, Generally it is 80-400 micrometers, 100-300 micrometers is preferable and 100-210 micrometers is more preferable.

The thermal transfer image-receiving sheet has at least a base sheet, a dye-receiving layer, and a porous layer formed between the dye-receiving layer and the base sheet, but has any other configuration as necessary. It may be. Examples of such other configurations include an undercoat layer formed between the porous layer and the base sheet, and a primer layer formed between the porous layer and the dye receiving layer. .

The primer layer is formed between the porous layer and the dye-receiving layer, and prevents image transfer to the porous layer side of the thermal transfer image-receiving sheet in a high-temperature and high-humidity environment. It has a function to improve. The primer layer is mainly composed of a thermoplastic resin forming the primer layer (hereinafter sometimes referred to as primer layer forming resin) and a cooling gelling agent, and a water-soluble polymer such as polyvinyl alcohol (PVA). It is also possible to form the layer from

The primer layer is preferably formed from a layer mainly composed of a primer layer forming resin and a cooling gelling agent. The primer layer-forming resin is a porous layer and a dye on a base sheet as a coating liquid for forming an aqueous primer layer together with a cooling gelling agent (hereinafter sometimes referred to as primer layer-forming coating liquid). Since it is desirable to form it together with the coating liquid for forming the receiving layer by the slide coating method, it is desirable to use it by emulsifying it in an aqueous solvent.

Examples of the primer layer forming resin include polyolefin resin, polyvinyl resin, polyester resin, polyurethane resin, polycarbonate resin, polyamide resin, poly (meth) acrylic acid resin, cellulose derivative resin, or polyether resin. Etc. In the present invention, any of these resins can be suitably used, but among them, a polyvinyl resin is preferably used. Examples of the polyvinyl resin include vinyl chloride-vinyl acetate copolymer, vinyl chloride-acrylic compound copolymer, ethylene-vinyl chloride-acrylic ester copolymer, ethylene-vinyl acetate-vinyl chloride copolymer, etc. Can be mentioned.

The primer layer preferably contains a cooling gelling agent. The cooling gelling agent used for the primer layer is the same as that described in the section of the “dye-receiving layer”, and the description thereof is omitted here.
When the primer layer containing the primer layer forming resin and the cooling gelling agent is used, the ratio of the primer layer forming resin and the cooling gelling agent is the primer layer forming ratio when forming the primer layer. There is no particular limitation as long as the desired viscosity characteristics can be imparted to the coating liquid. For example, in the primer layer forming coating solution, it is preferable that the cooling gelling agent is contained in a solid content in a proportion of 1 to 50% by mass. When the content of the cooling gelling agent is less than the above range, for example, when applying the dye-receiving layer-forming coating liquid on the substrate sheet, unevenness or the like may easily occur, When the above range is exceeded, for example, the adhesion to other layers may be lowered. A more preferable content of the cooling gelling agent is 2 to 40% by mass, and a more preferable content is 4 to 75% by mass.

Examples of water-soluble polymers that can be used for the primer layer formation include acrylic polymers such as sodium polyacrylate, polyacrylamide, and copolymers thereof, and vinyl polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, and polyvinyl pyrrolidone. Examples of other polymers such as polymers include polyethylene glycol, polypropylene glycol, polyisopropylacrylamide, polymethyl vinyl ether, polyethyleneimine, maleic acid copolymer, maleic acid monoester copolymer, and water-soluble polyester.
Among the water-soluble polymers, polyvinyl alcohol, its completely saponified product, partially saponified product, and modified polyvinyl alcohol are preferably used. Polyvinyl alcohol can be adjusted in viscosity and stabilized by an additive.

In addition to the primer layer-forming resin and the cooling gelling agent, the primer layer includes, for example, a nonionic silicone-based surfactant, a curing agent such as an isocyanate compound, a wetting agent, and a dispersing agent. It may be.

Although it does not specifically limit as thickness of the said primer layer, For example, it is preferable that it is 1-40 micrometers, 1-20 micrometers is more preferable, and 1-10 micrometers is still more preferable.

The undercoat layer is formed between the base sheet and the porous layer and has a function of improving the adhesion between the base sheet and the porous layer.
The undercoat layer is not particularly limited as long as the adhesion between the base sheet and the porous layer can be improved to a desired level, but (i) a resin that forms the undercoat layer (hereinafter, It is preferably formed from a layer mainly composed of an undercoat layer-forming resin) and a cooling gelling agent, but (ii) a water-soluble polymer or the like can also be used.
In addition, (i) undercoat layer forming resin and cooling gelling agent, and (ii) water-soluble polymer in the undercoat layer are the primer layer forming resin, cooling gelling agent, and water-soluble polymer described in the primer layer. And the description thereof is omitted.
The undercoat layer contains, in addition to the undercoat layer-forming resin and the cooling gelling agent, for example, a nonionic silicone-based surfactant, a curing agent such as an isocyanate compound, a wetting material, a dispersant, and the like. May be. The curing agent is particularly effective when, for example, a thermoplastic resin having active hydrogen is used as the undercoat layer forming resin.

The coating liquid for forming the undercoat layer (hereinafter sometimes referred to as an undercoat layer forming coating liquid) may contain hollow particles. When hollow particles are contained in the coating liquid for forming the undercoat layer, the hollow particles are preferably in the range of 20 to 90% by mass, and more preferably 40 to 80% by mass as the solid content. In addition, about the hollow particle used for the said undercoat layer forming coating liquid, since it is the same as that used for the porous layer mentioned above, description here is abbreviate | omitted.
As solid content concentration in the coating liquid for undercoat layer formation, 2-10 mass% is more preferable within the range of 1-50 mass%, for example. If the solid content concentration is too low, the drying time may become longer, and if the solid content concentration is too high, the storage stability of the coating liquid may be lowered and the viscosity may increase.

As a method for producing the thermal transfer image-receiving sheet, for example, a simultaneous multilayer coating step (1) in which at least a porous layer-forming coating solution and a dye-receiving layer-forming coating solution are simultaneously coated on a substrate sheet, It is preferable to have a cooling treatment step (2) for cooling the coating film composed of a plurality of layers formed on the substrate sheet, and a drying step (3) for drying the coating film cooled in the cooling treatment step. .

Examples of the method for simultaneously applying and forming a plurality of layers including a dye receiving layer on the base material sheet in the simultaneous multilayer coating step (1) include a gravure method, a curtain method, and a slide method. Above all, the surface tension and viscosity of the coating liquid of each layer is adjusted, and the coating liquid that forms each layer with a uniform thickness is slid and applied without overlapping each other. A coating method is preferred.

The slide coating method is, for example, a method in which a plurality of coating liquids constituting each layer of the thermal transfer image receiving sheet are applied to a base sheet wound around a back roll while being stacked one above the other. From the viewpoint of coating quality, the slide coating method is excellent in film thickness uniformity, and since there is no rotating part, quality defects due to scattering of the coating liquid are unlikely to occur, and there is no friction part, so there is no friction part. There is an advantage that loss due to cutting is less likely to occur. Also, from the viewpoint of handling properties of the coating liquid, the slide coating method can use a coating liquid that is less likely to change in concentration, viscosity, and composition of the coating liquid and that has high reactivity and changes over time. Further, since the coating liquid can be used up, waste is hardly generated, and since a high solid content coating liquid can be used, there is an advantage that the amount of solvent used can be reduced.

In the simultaneous multilayer coating step (1), a plurality of layers are simultaneously coated on the substrate sheet. (I) A porous layer, a dye receiving layer on the substrate sheet, (ii) On the substrate sheet An undercoat layer, a porous layer, a dye receiving layer, (iii) a porous layer, a primer layer, a dye receiving layer on a substrate sheet, and (iv) an undercoat layer, a porous layer, a primer layer on a substrate sheet. An embodiment in which the dye receiving layer is applied simultaneously can be mentioned.
In the simultaneous multilayer coating step (1), among the above-described modes, the above (iv) mode in which the undercoat layer, the porous layer, the primer layer, and the dye receiving layer are simultaneously coated on the substrate sheet is preferable. According to such an embodiment, it is possible to obtain a thermal transfer image receiving sheet having excellent adhesion between layers and excellent printing sensitivity.

As the porous layer forming coating solution and the dye receiving layer forming coating solution, the porous layer forming coating solution described in the above-mentioned "porous layer" and "dye receiving layer" section, and The thing similar to the coating liquid for dye receiving layer formation can be mentioned.

Next, the cooling process step (2) will be described. The step (2) is a step of cooling the plurality of coating films formed on the substrate sheet in the simultaneous multilayer coating step (1).
The method for cooling the plurality of coating films formed on the substrate sheet in the cooling treatment step (2) is not particularly limited as long as the method can cool the coating films to a desired temperature. As such a method, for example, a method of applying the coating film on a cooled substrate sheet, a surface of a roll that conveys the substrate sheet is cooled, and the coating film is applied via the substrate sheet. Examples thereof include a method of cooling, a method of spraying cold air on the coating film, and a method of passing the substrate sheet on which the coating film is formed through a cooling zone adjusted to a room temperature below a desired temperature. In particular, in the step, it is preferable to use a method of applying the coating film on a cooled substrate sheet. According to such a method, since the coating film can be forcibly cooled immediately after the coating film is applied on the base sheet, it is prevented that a plurality of layers constituting the coating film are mixed. it can.

In the cooling treatment step (2), the temperature for cooling the coating film is particularly limited as long as the viscosity of each layer constituting the coating film can be improved to such an extent that the layers do not mix with each other. It is not a thing.
Moreover, the cooling temperature in the said cooling process process (2) also depends on the kind of cooling gelling agent mentioned above. Especially in this process, 0-30 degreeC is preferable, as for cooling temperature, 0-25 degreeC is more preferable, and also 3-20 degreeC is especially preferable.

Next, the said drying process (3) is demonstrated. The step (3) is a step of drying the plurality of coating films cooled in the cooling treatment step (2). By drying the coating film in the step (3), these coating films can be cured to obtain a dye-receiving layer having excellent releasability.
In the said drying process (3), 30 to 90 degreeC is preferable and, as for the temperature which dries the coating film cooled in the said cooling process process, 40 to 60 degreeC is more preferable. The method for drying the coating film is not particularly limited as long as the aqueous solvent remaining in the coating film can be reduced to a predetermined amount or less within a predetermined time. About such a drying method, generally a well-known method can be used as a method of drying a coating film.

(Image forming method)
As a method of forming an image using the thermal transfer sheet of the present invention and the above-described thermal transfer image-receiving sheet, the thermal transfer sheet of the present invention and the above-mentioned thermal transfer image-receiving sheet are overlapped with each other on the base material of the thermal transfer sheet. On the other hand, from the surface side different from the surface type on which the dye layer is present (for example, the heat-resistant slipping layer side), a portion corresponding to the printing portion is heated and pressurized using a thermal head or the like, and corresponds to the printing portion of the dye layer. Examples include a method in which a dye (yellow dye and cyan dye) at a portion to be transferred is transferred to the thermal transfer image-receiving sheet as a transfer material by a thermal diffusion transfer method (sublimation thermal transfer method) and printed to form an image. it can.
As described above, when a green image is formed using the thermal transfer sheet of the present invention and the above-described thermal transfer image-receiving sheet, a green image having excellent light resistance, high sensitivity and high density can be suitably formed. Such an image forming method is also one aspect of the present invention.
The printer used when performing thermal transfer is not particularly limited, and a known thermal transfer printer can be used.
Thus, the printed matter obtained by the above image forming method using the thermal transfer sheet of the present invention and the above-described thermal transfer image receiving sheet is also one aspect of the present invention.

The green image obtained by the above image forming method using the thermal transfer sheet of the present invention preferably has an optical density (OD value) of 1.5 or more at the highest achieved density, and preferably 2.0 or more. More preferred.
The optical density can be determined using a commercially available spectrophotometer SpectroLino (manufactured by Gretag Macbeth, light source: D65, viewing angle: 2 °, density measurement filter: ANSI Status A).

In addition, a green image obtained by the above image forming method using the thermal transfer sheet of the present invention is xenon weatherweather (Atlas, Ci4000: black panel temperature 45 ° C., filter: CIRA, soda lime, 30 ° C. in the testing machine. It is preferable that the hue change ΔE * ab before and after irradiation is 10.0 or less when irradiation is performed for 96 hours at 30%, ultraviolet light with irradiation control of 420 nm fixed at 1.2 w / m ² . More preferably, it is 0 or less.
The above ΔE * ab is ΔE * ab in the vicinity of OD = 1 before irradiation = ((post-irradiation L * −pre-irradiation L *) ² + (post-irradiation a * −pre-irradiation a *) ² + (post-irradiation b * -Before irradiation b *) ² ) ^1/2 ; (where L *, a * and b * are based on the CIE 1976 L * a * b * color system, L * is the lightness, a * and b * represents a perceptual chromaticity index.)

Since the thermal transfer sheet of the present invention has the above-described configuration, it is excellent in light resistance, and can form a green image with high sensitivity and high density. For this reason, the thermal transfer sheet of the present invention can be suitably applied to an image forming method using a sublimation thermal transfer system.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples and comparative examples.
In the text, “part” or “%” is based on mass unless otherwise specified.

Production Example 1
A dye ink and a thermal transfer sheet were prepared according to the following procedure.
(Preparation of dye ink)
The following components were mixed and dispersed to prepare yellow dye ink and cyan dye ink, respectively.
<Yellow dye ink composition>
Dye (2-1) 2.3 parts by mass Dye (3-1) 2.4 parts by mass Solvent (Toluene / MEK = 1/1) 91.8 parts by mass Polyvinyl acetal resin (ESREC KS-5, Sekisui Chemical Co., Ltd.) 3.5 parts by mass <Cyan dye ink composition>
Dye (4-1) 3.5 parts by mass Dye (5-1) 3.0 parts by mass Solvent (Toluene / MEK = 1/1) 90 parts by mass Polyvinyl acetal resin (ESREC KS-5, manufactured by Sekisui Chemical Co., Ltd.) 3.5 parts by weight

(Preparation of thermal transfer sheet)
As a base sheet, the above dye ink was applied to a polyethylene terephthalate film having a thickness of 4.5 μm by gravure coating so that the dry coating amount was 0.6 g / m ² and dried at 80 ° C. for 2 minutes. Then, a yellow dye layer and a cyan dye layer were formed in the surface order to produce a thermal transfer sheet.
In addition, a heat-resistant slipping layer coating solution having the following composition was applied to the other surface of the base sheet with a wire bar in advance so that the dry coating amount was 1.0 g / m ² , dried, and heat-resistant A slipping layer was formed.

<Heat resistant slipping layer coating solution composition>
Polyvinyl butyral resin (ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.) 13.6 parts by mass polyisocyanate curing agent (Takenate D218, manufactured by Takeda Pharmaceutical Co., Ltd.) 0.6 parts by mass phosphate ester (Plysurf A208S, Daiichi Kogyo) (Manufactured by Pharmaceutical Co., Ltd.) 0.8 parts by mass methyl ethyl ketone 42.5 parts by mass toluene 42.5 parts by mass

Production Examples 2-8
Except having changed the composition of each dye ink as shown in Table 1, the thermal transfer sheets of Production Examples 2 to 8 were produced in the same manner as Production Example 1. In addition, the dye (1-1), the dye (2-1), the dye (3-1), the dye (4-1), the dye (5-1), and the dyes A to G in Table 1 are as follows. It is.

Production Example 9 Production of thermal transfer image-receiving sheet Thermal transfer image-receiving sheet 1 was produced by the following method.
(1) Preparation of thermal transfer image-receiving sheet 1 RC paper (product name: STF-150, manufactured by Mitsubishi Paper Industries Co., Ltd.) was used as a base sheet, and a porous layer-forming coating solution 1 having the following composition and a dye-receiving layer-forming coating were used. The working fluid 1 is heated to 50 ° C., applied by slide coating to a thickness of 30 μm and 5 μm, respectively, cooled and gelled at 5 ° C. for 1 minute, and then at 50 ° C. for 5 minutes. It dried and the thermal transfer image receiving sheet 1 was obtained.

(I) Porous layer forming coating solution 1
Hollow particles (Rohm and Haas, trade name: HP-91) (as solids) 70 parts by weight Gelatin (Nitta Gelatin, trade name: RR) (as solids) 30 parts by weight surfactant (day Product name: Surfynol 440, manufactured by Shin Chemical Industry Co., Ltd. In a 1 part by mass porous layer forming coating solution, the above components were diluted with water so that the total solid content was 17% by mass.

(Ii) Dye-receiving layer forming coating solution 1
Emulsion 1 (as solids) 90 parts by weight gelatin (made by Nitta Gelatin, trade name: RR) (as solids) 10 parts by weight silicone release agent (made by Shin-Etsu Chemical Co., Ltd., trade name: KF615A) 10 parts by weight Part surfactant (manufactured by Nissin Chemical Industry Co., Ltd., trade name: Surfinol 440) In 1 part by weight of the dye-receiving layer forming coating solution, the above components are diluted with water so that the total solid content is 25% by weight did.
The method for synthesizing emulsion 1 is shown below.

(Iii) Synthesis of Emulsion 1 In a 500 mL (liter) Erlenmeyer flask, 121 g of styrene, 77 g of ethyl acrylate and 2 g of acrylic acid as copolymer forming monomers, and Aqualon HS-10 (Daiichi Kogyo Seiyaku Co., Ltd.) 1 as an emulsifier .9 g was added and stirred and mixed (hereinafter referred to as monomer A). In a 1 L three-necked flask, 200 g of distilled water was added and heated to 80 ° C., and about 20% of the total amount of monomer A was added and stirred for 10 minutes. Thereafter, 0.4 g of ammonium persulfate dissolved in 20 g of pure water was added and stirred for 10 minutes, and then the remaining 80% of the monomer A was dropped with a dropping funnel over 3 hours and further stirred for 3 hours. Thereafter, the mixture was cooled to room temperature and filtered through # 150 mesh (Japanese woven fabric) to obtain Emulsion 1 (molecular weight 240000, Tg 50 ° C.). Further, from the molecular weight of styrene and ethyl acrylate and the amount used for the reaction, the respective molar ratios are 60% and 40%.

Production Example 10 Production of thermal transfer image receiving sheet 2 The thermal transfer image receiving sheet 2 was produced by the following method.
(2) Preparation of thermal transfer image-receiving sheet 2 As a base sheet, an adhesive layer coating liquid having the following composition is applied to the surface of the 39 μm-thick microvoided film of the fine void layer on the side opposite to the surface on which the dye receiving layer described later is formed. It was applied and dried, and the coated paper (186.1 g / m ² ), which was a support provided with a back layer on one side under the following conditions, was adhered to the surface on which the back layer was not laminated. A primer layer coating solution having the following composition was applied to the surface to be coated with the receiving layer by wire bar coating so that the dry coating amount was 2.0 g / m ² and dried to form a primer layer. On the primer layer, the dye receiving layer coating solution 2 having the following composition was applied by wire bar coating so that the dry coating amount was 4.0 g / m ² and dried (110 ° C., 1 minute). A dye-receiving layer was formed to obtain a thermal transfer image-receiving sheet 2.

(I) Adhesive layer coating liquid polyfunctional polyol (Takelac A-969V, manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.) 30 parts by mass isocyanate (Takenate A-5, manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.) 10 parts by mass Ethyl acetate 60 parts by mass

(Ii) Conditions for forming the back surface layer Using a coated paper with a basis weight of 157 g / m ² , after applying corona discharge treatment on one side, high-density polyethylene was applied to the surface as a back side grip layer by extrusion coating (basis weight 29.1 g / m ² ) to provide a back layer on the coated paper.

(Iii) Primer layer coating liquid polyester polyol (manufactured by Toyo Morton, Adcoat) 15.0 parts by mass Methyl ethyl ketone / toluene (mass ratio 2: 1) 85.0 parts by mass

(Iv) Dye-receiving layer coating solution 2
Vinyl chloride-vinyl acetate copolymer resin (Solvine C manufactured by Nissin Chemical Industry Co., Ltd., PVC / vinyl acetate = 87/13, number average molecular weight 31000, Tg 70 ° C.) 20.0 parts by mass carboxyl-modified silicone (Shin-Etsu Chemical Co., Ltd.) Manufactured, X-22-3701E) 1.0 part by mass methyl ethyl ketone / toluene (mass ratio 1: 1) 79.0 parts by mass

Examples 1-2 and Comparative Examples 1-6
<Image density and hue change>
Using the thermal transfer image-receiving sheet 1 or 2 of Production Examples 9 and 10 as a transfer target, the dye layer of the thermal transfer sheet obtained in Production Examples 1 to 8 and the dye receiving surface of the transfer target are opposed to each other. At the same time, thermal transfer recording was performed from the back side of the thermal transfer sheet using a thermal head, and green gradation images with equal printing energy were formed. Further, after the image formation, an overcoat of a ribbon exclusively for the P-400 printer (made by OLYMPUS) was thermally transferred.
Table 1 shows the thermal transfer sheet and thermal transfer image receiving sheet used in each example and comparative example.
(Printing conditions)
・ Thermal head: F3598 (Toshiba Hokuto Electronics Co., Ltd.)
-Heating element average resistance: 5176 (Ω)
・ Print density in the main scanning direction: 300 dpi
-Sub-scanning direction printing density: 300 dpi
・ Printing power: 0.12 (W / dot)
1 line cycle: 2 (msec.)
・ Pulse duty: 85%
-Printing start temperature: 35.5 (° C)

(Colorimetric conditions)
Colorimeter: Spectrometer SpectroLino (manufactured by Gretag Macbeth)
・ Light source: D65
-Viewing angle: 2 °
Concentration filter: ANSI Status A

The obtained green image was converted to xenon weatherweather (Atlas, Ci4000: black panel temperature 45 ° C., filter: CIRA, soda lime, 30% 30 ° C. in the test machine, UV light with irradiation control 420 nm to 1.2 w / m ² . (Fixed) for 96 hours, hue change before and after irradiation (ΔE * ab near OD = 1 before irradiation = ((post-irradiation L * −pre-irradiation L *) ² + (post-irradiation a * −pre-irradiation a) *) ² + (post-irradiation b * −pre-irradiation b *) ² ) ^1/2 ; (where L *, a * and b * are based on the CIE 1976 L * a * b * color system, L * was the lightness, and a * and b * were the perceptual chromaticity index.) The results are shown in Table 1. As the image density, the highest achieved density before irradiation is shown in Table 1. .

From Table 1, in the examples, green images with excellent light resistance, high sensitivity and high density were obtained. On the other hand, in the comparative example, a green image having desired light resistance and density was not obtained.

The thermal transfer sheet of the present invention can be suitably applied to an image forming method using a sublimation type thermal transfer system.

Claims (5)

A thermal transfer sheet having at least a yellow dye layer and a cyan dye layer on a substrate sheet,
The dye contained in the yellow dye layer is selected from the group consisting of a compound represented by the general formula (1), a compound represented by the general formula (2), and a compound represented by the general formula (3). Consisting of at least one
The dye contained in the cyan dye layer comprises a compound represented by the general formula (4) and / or a compound represented by the general formula (5),
The thermal transfer sheet is used to form an image in combination with a thermal transfer image-receiving sheet having at least a dye-receiving layer and a porous layer on another substrate sheet,
The dye-receiving layer contains a styrene-acrylic copolymer (a), a cooling gelling agent (b) and a release agent (c),
The styrene-acrylic copolymer (a) has a molar ratio of styrene units to acrylic compound units ([styrene unit] / [acrylic compound]) of 60 to 80/40 to 20. Heat transfer sheet.

In the general formula (1), R ¹ represents a hydrogen atom, a substituted or unsubstituted alkyl group, or an alkoxy group,
R ² represents an alkoxycarbonyl group, an alkylaminocarbonyl group, an alkoxy group, an alkoxyalkoxy group, an alkyl group, a cycloalkyl group, or a heterocyclic group,
X represents a hydrogen atom or a halogen atom. ;

In the general formula (2), R ³ and R ⁴ are the same or different functional groups, and are a substituted or unsubstituted lower alkyl group, a substituted or unsubstituted lower alkenyl group, or a substituted or unsubstituted aryl. Represents a group,
R ⁵ and R ⁶ are the same or different functional groups and represent a substituted or unsubstituted lower alkyl group. ;

In the general formula (3), R ⁷ and R ⁸ are the same or different functional groups, and are a hydrogen atom, a substituted or unsubstituted alkyl group, an allyl group, a substituted or unsubstituted aryl group, or cycloalkyl. Represents a group,
R ⁹ is a hydrogen atom, a substituted or unsubstituted alkyl group, an NR ¹¹ R ¹² group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkoxycarbonyl group, a substituted or unsubstituted aryl group, or C ( O) represents an NR ¹³ R ¹⁴ group,
R ¹⁰ represents a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group,
R ¹¹ , R ¹² , R ¹³ and R ¹⁴ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group;

In the general formulas (4) and (5), R ¹⁵ and R ¹⁶ are the same or different functional groups, and are substituted or unsubstituted alkyl groups, substituted or unsubstituted cycloalkyl groups, or substituted or non-substituted groups. Represents a substituted aralkyl group,
R ¹⁷ represents a substituted or unsubstituted alkoxycarbonyl group, a substituted or unsubstituted alkylaminocarbonyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a heterocyclic ring Represents a group or a halogen atom,
R ¹⁸ represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylcarbonylamino group, a substituted or unsubstituted alkylsulfonylamino group, a substituted or unsubstituted alkylaminocarbonyl group, Represents a substituted or unsubstituted alkylaminosulfonyl group, or a halogen atom;
R ¹⁹ represents CONHR ²¹ , SO ₂ NHR ²¹ , NHCOR ²² , NHSO ₂ R ²² or a halogen atom;
R ²⁰ represents a substituted or unsubstituted alkyl group,
X represents a halogen atom,
R ²¹ represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aromatic heterocyclic group;
R ²² represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aromatic heterocyclic group. Represents. The dye contained in the yellow dye layer is selected from the group consisting of a compound represented by formula (1-1), a compound represented by formula (2-1), and a compound represented by formula (3-1). Consisting of at least one kind selected
The thermal transfer sheet according to claim 1, wherein the dye contained in the cyan dye layer comprises a compound represented by formula (4-1) and / or a compound represented by formula (5-1).

A thermal transfer sheet having at least a yellow dye layer and a cyan dye layer on the base sheet;
An image forming method for forming an image using a thermal transfer image receiving sheet having at least a dye receiving layer and a porous layer on another substrate sheet,
The dye contained in the yellow dye layer is selected from the group consisting of a compound represented by the general formula (1), a compound represented by the general formula (2), and a compound represented by the general formula (3). Consisting of at least one
The dye contained in the cyan dye layer comprises a compound represented by the general formula (4) and / or a compound represented by the general formula (5),
The dye-receiving layer of the thermal transfer image-receiving sheet contains a styrene-acrylic copolymer (a), a cooling gelling agent (b) and a release agent (c),
The styrene-acrylic copolymer (a) has a molar ratio of styrene units to acrylic compound units ([styrene unit] / [acrylic compound]) of 60 to 80/40 to 20. Image forming method.

In the general formula (1), R ¹ represents a hydrogen atom, a substituted or unsubstituted alkyl group, or an alkoxy group,
R ² represents an alkoxycarbonyl group, an alkylaminocarbonyl group, an alkoxy group, an alkoxyalkoxy group, an alkyl group, a cycloalkyl group, or a heterocyclic group,
X represents a hydrogen atom or a halogen atom. ;

In the general formula (2), R ³ and R ⁴ are the same or different functional groups, and are a substituted or unsubstituted lower alkyl group, a substituted or unsubstituted lower alkenyl group, or a substituted or unsubstituted aryl. Represents a group,
R ⁵ and R ⁶ are the same or different functional groups and each represents a substituted or unsubstituted lower alkyl group. ;

In the general formula (3), R ⁷ and R ⁸ are the same or different functional groups, and are a hydrogen atom, a substituted or unsubstituted alkyl group, an allyl group, a substituted or unsubstituted aryl group, or cycloalkyl. Represents a group,
R ⁹ is a hydrogen atom, a substituted or unsubstituted alkyl group, an NR ¹¹ R ¹² group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkoxycarbonyl group, a substituted or unsubstituted aryl group, or C ( O) represents an NR ¹³ R ¹⁴ group,
R ¹⁰ represents a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group,
R ¹¹ , R ¹² , R ¹³ and R ¹⁴ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group;

In the general formulas (4) and (5), R ¹⁵ and R ¹⁶ are the same or different functional groups, and are substituted or unsubstituted alkyl groups, substituted or unsubstituted cycloalkyl groups, or substituted or non-substituted groups. Represents a substituted aralkyl group,
R ¹⁷ represents a substituted or unsubstituted alkoxycarbonyl group, a substituted or unsubstituted alkylaminocarbonyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a heterocyclic ring Represents a group or a halogen atom,
R ¹⁸ represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylcarbonylamino group, a substituted or unsubstituted alkylsulfonylamino group, a substituted or unsubstituted alkylaminocarbonyl group, Represents a substituted or unsubstituted alkylaminosulfonyl group, or a halogen atom;
R ¹⁹ represents CONHR ²¹ , SO ₂ NHR ²¹ , NHCOR ²² , NHSO ₂ R ²² or a halogen atom;
R ²⁰ represents a substituted or unsubstituted alkyl group,
X represents a halogen atom,
R ²¹ represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aromatic heterocyclic group;
R ²² represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aromatic heterocyclic group. Represents. The dye contained in the yellow dye layer is selected from the group consisting of a compound represented by formula (1-1), a compound represented by formula (2-1), and a compound represented by formula (3-1). Consisting of at least one kind selected
The image forming method according to claim 3, wherein the dye contained in the cyan dye layer comprises a compound represented by Formula (4-1) and / or a compound represented by Formula (5-1).

A printed matter obtained by the image forming method according to claim 3.