Ink and sheet for thermal transfer recording

Abstract

This ink comprises a medium and carrier particles that are dyed with a compound represented by general formula (1), a compound represented by general formula (2), and a compound represented by general formula (3).

Description

Ink and Sheet for Thermal Transfer Recording

[0001] The present invention relates to an ink and a sheet for thermal transfer recording.

[0002] In the apparel field, a large amount of industrial wastewater generated in the dyeing process for various fabrics is regarded as a problem from the viewpoint of environmental load. Therefore, digital textile printing methods using an inkjet method or an electrophotographic method have been actively developed in recent years as a method that can provide printed products with low energy and low cost. Examples include a method using an ink containing a pigment, a method using an ink containing resin particles dyed with a dye, and a method using an ink containing a sublimable dye.

[0003] Aqueous inks containing pigments (aqueous pigment inks) are excellent in light resistance, but have a problem that color development tends to be low. In addition, for inks containing resin particles dyed with a dye, it is difficult to achieve both light resistance and color development.

[0004] For example, inkjet inks using resin particles colored with anthraquinone dyes, azo dyes, or methine dyes as colorants have been reported, but according to studies by the present inventor, it has been found that further improvement in light resistance is required.

[0005] Furthermore, in the field of writing instruments (especially ballpoint pens), there is a growing demand for differences in ink and functionality to meet user requirements such as writing feel, initial writing performance, and consistent handwriting. Ballpoint pens come in various types, including oil-based ballpoint pens, water-based ballpoint pens, and gel ink ballpoint pens, and in a variety of colors such as black, red, blue, yellow, pink, green, and orange. Dyes, pigments, and mixtures thereof are used as colorants in inks. For example, oil-based inks using pigments have excellent ink fastness, but they have storage stability problems because the pigments tend to aggregate or settle in the ink, and using oil-based inks where the pigments have aggregated or settled can result in problems with the handwriting. In contrast, oil-based inks using dyes have the characteristic that the dyes are easily soluble in solvents, so they are less prone to aggregation and settling compared to pigments and have better storage stability, but tend to have poor lightfastness. For example, Patent Document 1 reports a ballpoint pen paste (ink for writing instruments) using anthraquinone dyes, azo dyes, or methine dyes as colorants.

[0006] Furthermore, in sublimation transfer image recording methods that use inks containing sublimation dyes, not only are high optical density images required, but color fluctuations due to heat press temperature must be suppressed to ensure color stability when repeatedly recording images. In addition, with the expansion of applications to sports apparel and other fields, the demand for lightfastness is also increasing. For example, Patent Document 2 reports an example of using an ink that combines a sublimation dye having fluorescence and a sublimation dye that does not have fluorescence.

[0007] Furthermore, sublimation dyes can also be used in image recording methods using a thermal transfer recording system that can be printed in a dry process, employing a thermal transfer recording sheet having a colorant layer containing sublimation dyes. In thermal transfer recording systems, each colorant layer is usually formed by mixing two to three types of compounds. Therefore, there has been a problem that color fading can occur due to mixing between compounds during image recording. For this reason, studies have been conducted to suppress this fading in thermal transfer recording sheets, and for example, Patent Document 3 proposes a solution by including a colorfastness inhibitor in the colorant layer. Patent Document 4 also reports a combination of yellow, magenta, and cyan colorants mixed to represent black.

[0008] Japanese Patent Publication No. Hei 8-20669, Japanese Patent Publication No. 2016-132756, Japanese Patent Publication No. 2001-158879, Japanese Patent Publication No. 2016-193545

[0009] However, our investigations have revealed that the inks described in Patent Documents 1 to 4 all have issues that need improvement. Specifically, the ink described in Patent Document 1 requires further improvement in terms of lightfastness. The ink described in Patent Document 2 does not have sufficient stability of image density due to differences in black image density and heat press temperature (hereinafter also referred to as color development stability), nor does it have sufficient lightfastness, and therefore requires further improvement. Furthermore, the inks described in Patent Documents 3 and 4 require further improvement in terms of fading due to color mixing (hereinafter also referred to as color mixing fading).

[0010] Therefore, an object of the present invention is to provide an ink with good storage stability and high lightfastness. Another object of the present invention is to provide an ink with high optical density and excellent color development stability and lightfastness during heat pressing. Furthermore, another object of the present invention is to provide a thermal transfer recording sheet that can suppress fading due to color mixing in the formulation of three types of colorants used in the black colorant layer of the thermal transfer recording sheet: yellow colorant, magenta colorant, and cyan colorant.

[0011] According to one aspect of the present invention, there is provided an ink characterized by comprising: a medium; and carrier particles dyed with a compound represented by the following general formula (1), a compound represented by the following general formula (2), and a compound represented by the following general formula (3).

[0012]

[0013] [In general formula (1), R １ represents a halogen atom, and R ２ and R ３ each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an aryl group. ];

[0014]

[0015] [In general formula (2), R ４ represents a -NH ２ group, a monoalkylamino group, a dialkylamino group, or an acetylamino group, R ５ represents a halogen atom, and R ６ represents a hydroxyl group or an alkoxy group. ];

[0016]

[0017] [In general formula (3), R ７ represents a hydrogen atom, an alkyl group, or an acetylamino group, and R ８ and R ９ each independently represent an alkyl group having 1 to 8 carbon atoms. ].

[0018] According to another aspect of the present invention, there is provided an ink characterized by comprising: an aqueous medium, a dispersant, a compound represented by the following general formula (1), a compound represented by the following general formula (2), and a compound represented by the following general formula (3).

[0019]

[0020] [In general formula (1), R １ represents a halogen atom, and R ２ and R ３ each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an aryl group. ];

[0021]

[0022] [In general formula (2), R ４ is, -NH ２ R represents a group, a monoalkylamino group, a dialkylamino group, or an acetylamino group. ５ R represents a halogen atom. ６ [This represents a hydroxyl group or an alkoxy group.]

[0023]

[0024] [In general formula (3), R ７ R represents a hydrogen atom, an alkyl group, or an acetylamino group. ８ and R ９ Each of these independently represents an alkyl group having 1 to 8 carbon atoms.

[0025] Furthermore, according to another aspect of the present invention, a thermal transfer recording sheet is provided, comprising a substrate and a black colorant layer formed on the substrate, wherein the black colorant layer contains a compound represented by the following general formula (1), a compound represented by the following general formula (2), and a compound represented by the following general formula (3).

[0026]

[0027] [In general formula (1), R １ represents a halogen atom, R ２ and R ３ Each of these independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an aryl group.

[0028]

[0029] [In general formula (2), R ４ is, -NH ２ R represents a group, a monoalkylamino group, a dialkylamino group, or an acetylamino group. ５ R represents a halogen atom. ６ [This represents a hydroxyl group or an alkoxy group.]

[0030]

[0031] [In general formula (3), R ７ R represents a hydrogen atom, an alkyl group, or an acetylamino group. ８ and R ９ Each of these independently represents an alkyl group having 1 to 8 carbon atoms.

[0032] According to one aspect of the present invention, an ink with good storage stability and high lightfastness can be provided. Furthermore, according to another aspect of the present invention, an ink with high optical density and excellent color development stability and lightfastness during heat pressing can be provided. In addition, according to yet another aspect of the present invention, a thermal transfer recording sheet can be provided in which discoloration due to mixing of yellow, magenta, and cyan pigments used in the black pigment layer of the thermal transfer recording sheet can be suppressed.

[0033] The present invention will be described in detail below.

[0034] <First Embodiment> As a result of diligent research to solve the above problems, the present inventors have found that by using a medium and carrier particles dyed with compounds represented by general formulas (1), (2), and (3), it is possible to provide an ink with good storage stability and high lightfastness.

[0035] Conventionally, inks using individual carrier particles of compounds represented by general formulas (1), (2), and (3) were prone to aggregation, resulting in problems with storage stability or lightfastness.

[0036] Through the inventors' research, it was found that by using carrier particles dyed with a combination of compounds represented by general formulas (1), (2), and (3), each of which have problems when used individually as colorants, an ink with good storage stability and high lightfastness can be obtained. The mechanism by which the above effects are produced by mixing these compounds represented by general formulas (1), (2), and (3) is not clearly understood, but the inventors speculate as follows.

[0037] The compounds represented by general formulas (1), (2), and (3) are structurally of similar size, and overlapping occurs between the three compounds due to π-π stacking interactions or hydrogen bonds between the benzene rings of each compound. We believe that the aforementioned effects are produced by the stabilization of the three compounds through this overlapping.

[0038] The configuration of the ink according to this embodiment will be described in detail below.

[0039] The ink according to this embodiment contains a medium and carrier particles dyed with compounds represented by general formulas (1), (2), and (3). The ink according to this embodiment is suitable as an ink because it has good storage stability and high lightfastness by using carrier particles dyed with three specific types of compounds.

[0040] [Colorants] (Compounds represented by general formula (1)) First, we will explain the compounds represented by the following general formula (1), which are yellow colorants.

[0041]

[0042] [In general formula (1), R １ represents a halogen atom, R ２ and R ３ Each of these independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an aryl group. In general formula (1), R １ The halogen atoms in this are not particularly limited. Specifically, examples include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms. Among these, chlorine atoms or bromine atoms are preferred because they make it easier to obtain a thermal transfer recording sheet in which color mixing and fading are suppressed in the three formulations of yellow, magenta, and cyan pigments used in the black pigment layer.

[0043] In general formula (1), R ２ and R ３The alkyl group having 1 to 8 carbon atoms is not particularly limited, but specifically, examples include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, tert-butyl group, and 2-ethylhexyl group. In particular, in the formulation of the three pigments used in the black pigment layer—yellow pigment, magenta pigment, and cyan pigment—it is easier to obtain a thermal transfer recording sheet in which color mixing and fading is suppressed, so methyl group, ethyl group, n-propyl group, or n-butyl group is preferred.

[0044] In general formula (1), R ２ and R ３ The aryl group in this compound is not particularly limited, but specifically, examples include phenyl groups and naphthyl groups. In particular, a phenyl group is preferred in the formulation of the three pigments used in the black pigment layer: yellow, magenta, and cyan, because it is easier to obtain a thermal transfer recording sheet in which color mixing and fading is suppressed.

[0045] Compounds represented by general formula (1) have azo-hydrazo tautomers, which are within the scope of this invention. In this paragraph and subsequent descriptions of chemical formulas, only structures similar to general formula (1) will be described, but both azo-hydrazo tautomers will be included. Furthermore, the compound represented by general formula (1) may be a mixture of these tautomers.

[0046] Preferred examples of compounds represented by general formula (1) are shown below as compounds (1-1) to (1-9), but the list is not limited to these compounds.

[0047]

[0048] The compound represented by the above general formula (1) may be used alone, or two or more may be used in combination to adjust the color tone, etc., depending on the application. Furthermore, it may be used in combination with known pigments and dyes to the extent that the effects of the present invention are not impaired. The known pigments and dyes used in combination may be one or two or more.

[0049] Among these, in general formula (1), R １ However, it is a chlorine atom, R２ is a methyl group, R ３ However, it is preferable that the alkyl group has 1 to 8 carbon atoms. In particular, it is preferable that it be compound (1-1) to (1-5). When any of these compounds are used, it is easier to obtain a thermal transfer recording sheet in which color mixing and fading are suppressed in the three formulations of yellow, magenta, and cyan pigments used in the black pigment layer.

[0050] Compounds represented by general formula (1) can be synthesized by known methods, but they can also be obtained commercially.

[0051] (Compound represented by general formula (2)) Next, we will explain the compound represented by general formula (2), which is a magenta colorant.

[0052]

[0053] [In general formula (2), R ４ is, -NH ２ R represents a group, a monoalkylamino group, a dialkylamino group, or an acetylamino group. ５ R represents a halogen atom. ６ [This represents a hydroxyl group or an alkoxy group.]

[0054] In general formula (2), R ４ The monoalkylamino group in this context is not particularly limited, but specific examples include monomethylamino group, monoethylamino group, monobutylamino group, etc. The dialkylamino group is not particularly limited, but specific examples include dimethylamino group, diethylamino group, etc. ４ Among them, -NH ２ The functional group is preferably a monomethylamino group or a dimethylamino group. These functional groups make it particularly easy to obtain a thermal transfer recording sheet in which color mixing and fading are suppressed in the three formulations of yellow, magenta, and cyan pigments used in the black pigment layer.

[0055] In general formula (2), R ５The halogen atoms in this are not particularly limited. Specifically, examples include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms. Among these, chlorine atoms or bromine atoms are preferred because they make it easier to obtain a thermal transfer recording sheet in which color mixing and fading are suppressed in the three formulations of yellow, magenta, and cyan pigments used in the black pigment layer.

[0056] In general formula (2), R ６ The alkoxy group in this is not particularly limited. Specifically, examples include methoxy, ethoxy, propoxy, butoxy, and phenoxy groups. ６ In particular, in the formulations of the yellow, magenta, and cyan pigments used in the black pigment layer, it is more preferable that the pigments be hydroxyl or methoxy groups, as this makes it easier to obtain a thermal transfer recording sheet in which color mixing and fading are suppressed.

[0057] Preferred examples of compounds represented by general formula (2) are shown below as compounds (2-1) to (2-9), but the list is not limited to these compounds.

[0058]

[0059] The compound represented by the above general formula (2) may be used alone, or two or more may be used in combination to adjust the color tone, etc., depending on the application. Furthermore, it may be used in combination with known pigments and dyes to the extent that the effects of the present invention are not impaired. The known pigments and dyes used in combination may be one or two or more.

[0060] Among these, in general formula (2), R ４ ga-NH ２ It is a group or a monomethylamino group, R ５ is a bromine atom, R ６It is preferable that the group is a hydroxyl group or a methoxy group. In particular, it is preferable that it is compound (2-2), (2-3), or (2-7). Using any of these compounds makes it easier to obtain a thermal transfer recording sheet in which color mixing and fading are suppressed in the three formulations of yellow, magenta, and cyan colorants used in the black colorant layer.

[0061] Compounds represented by general formula (2) can be synthesized by known methods, but they can also be obtained commercially.

[0062] (Compounds represented by general formula (3)) Next, we will explain the compounds represented by general formula (3) that are cyan colorants.

[0063]

[0064] [In general formula (3), R ７ R represents a hydrogen atom, an alkyl group, or an acetylamino group. ８ and R ９ Each of these independently represents an alkyl group having 1 to 8 carbon atoms.

[0065] In general formula (3), R ７ The alkyl group in is not particularly limited, but specifically, examples include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, and tert-butyl group. Among these, linear or branched alkyl groups having 1 to 4 carbon atoms are preferred. In particular, in the formulation of the three pigments used in the black pigment layer—yellow pigment, magenta pigment, and cyan pigment—a thermal transfer recording sheet in which color mixing and fading is suppressed is easily obtained, so a methyl group or ethyl group is preferred, and a methyl group is particularly preferred.

[0066] In general formula (3), R ８ and R ９The alkyl group having 1 to 8 carbon atoms is not particularly limited, but specifically, examples include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, tert-butyl group, and 2-ethylhexyl group. In particular, in the formulation of the three pigments used in the black pigment layer—yellow pigment, magenta pigment, and cyan pigment—it is easier to obtain a thermal transfer recording sheet in which color mixing and fading is suppressed, so methyl group, ethyl group, n-propyl group, or n-butyl group is preferred.

[0067] Compounds represented by general formula (3) have azo-hydrazo tautomers, which are within the scope of the present invention. In this paragraph and subsequent descriptions of chemical formulas, only structures similar to general formula (3) will be described, but both azo-hydrazo tautomers will be included. Furthermore, compounds represented by general formula (3) may be mixtures of these tautomers.

[0068] Preferred examples of compounds represented by general formula (3) are shown below as compounds (3-1) to (3-5), but the list is not limited to these compounds.

[0069]

[0070] The compound represented by the above general formula (3) may be used alone, or two or more may be used in combination to adjust the color tone, etc., depending on the application. Furthermore, it may be used in combination with known pigments and dyes to the extent that the effects of the present invention are not impaired. The known pigments and dyes used in combination may be one or two or more.

[0071] Among these, in general formula (3), R ７ R is a methyl group or an acetylamino group, ８ and R ９ However, it is more preferable that each of them be an alkyl group having 1 to 4 carbon atoms. In particular, compounds (3-3) to (3-5) are preferred. Using any of these compounds makes it easier to obtain a thermal transfer recording sheet in which color mixing and fading are suppressed in the three formulations of yellow, magenta, and cyan colorants used in the black colorant layer.

[0072] Compounds represented by general formula (3) can be synthesized by known methods, but they can also be obtained commercially.

[0073] In the ink of this embodiment, the total amount of the compound represented by general formula (1), the compound represented by general formula (2), and the compound represented by general formula (3) is not particularly limited. Preferably, it is 0.5% by mass or more and 10.0% by mass or less, based on the total mass of the ink, and more preferably 1.0% by mass or more and 7.0% by mass or less.

[0074] Furthermore, the blending ratio of the compound represented by general formula (1), the compound represented by general formula (2), and the compound represented by general formula (3) is not particularly limited. Preferably, the blending ratio (mass ratio) of the compound represented by general formula (1), the compound represented by general formula (2), and the compound represented by general formula (3) is as follows: For every 10 parts by mass of the compound represented by general formula (1), it is preferable that the compound represented by general formula (2) is 3 to 9 parts by mass, and the compound represented by general formula (3) is 1 to 6 parts by mass. In particular, it is more preferable that the compound represented by general formula (2) is 4 to 8 parts by mass, and the compound represented by general formula (3) is 2 to 5 parts by mass. It is even more preferable that the compound represented by general formula (2) is 4 to 6 parts by mass, and the compound represented by general formula (3) is 2 to 4 parts by mass. By using carrier particles dyed with colorants within this range, it is easy to obtain an ink with good storage stability and high lightfastness.

[0075] In the ink of this embodiment, as described above, at least one compound represented by general formulas (1), (2), and (3) is used as a coloring agent in combination. However, known coloring agents may also be used in combination, as long as they do not impede solubility or dispersibility in the medium. Examples include condensed azo compounds, azo metal complexes, methine compounds, etc.

[0076] In the ink of this embodiment, the content of the colorant is set appropriately according to the application and is not particularly limited. Preferably, the total amount including any known colorant is 1.0 part by mass or more and 30.0 parts by mass or less based on 100 parts by mass of the medium, more preferably 2.0 parts by mass or more and 20.0 parts by mass or less, and even more preferably 3.0 parts by mass or more and 15.0 parts by mass or less. Within the above range, sufficient coloring power can be obtained and the dispersibility of the colorant is also good.

[0077] [Carrier Particles] In this specification, "carrier particles" means carriers that are dispersed in a medium and may exist in the medium in a state having particle size. Carrier particles exist dispersed in the ink. When the medium is an aqueous medium, they exist dispersed in the aqueous medium, i.e., in the state of a carrier emulsion.

[0078] In carrier particles stained with a coloring agent, the coloring agent is dispersed or present within the carrier particles.

[0079] The cumulative 50% particle size (D50) of the volume-based particle size distribution of the carrier particles is preferably between 140 nm and 300 nm. A D50 of 140 nm or higher can suppress a decrease in image lightfastness. On the other hand, a D50 of 300 nm or lower can suppress a decrease in ink ejection stability.

[0080] When dyeing carrier particles with compounds represented by general formulas (1), (2), and (3), the mixing ratio (mass ratio) of the compounds represented by general formulas (1), (2), and (3) to the carrier particles is not particularly limited. On a mass basis, it is preferable that the total amount of compounds represented by general formulas (1), (2), and (3) is 0.5 parts by mass or more and 20 parts by mass or less, and more preferably 1 part by mass or more and 10 parts by mass or less, per 100 parts by mass of carrier particles.

[0081] Furthermore, the content of dyed carrier particles is preferably 1% by mass or more and 10% by mass or less, based on the total amount of ink, and more preferably 3% by mass or more and 6% by mass or less.

[0082] Examples of carrier particles include resins and cellulose nanofibers. Examples of resin types include styrene polymers, acrylic acid polymers, methacrylic acid polymers, polyester resins, polyvinyl ether resins, polyvinyl methyl ether resins, polyvinyl alcohol resins, polyvinyl butyral resins, polyurethane resins, polypeptide resins, etc. These resins may be used individually or in combination of two or more as needed. When the carrier particles are formed from resin, they are sometimes also referred to as "resin particles." From the viewpoint of ease of dyeing with colorants, it is preferable that the carrier particles be resin particles.

[0083] Cellulose nanofibers are selected according to their application, but for example, they can be obtained by chemically and / or mechanically defibrating plant fibers. They are extremely fine fibers with an average width of several nm to 20 nm and an average length of 0.5 μm to several μm. The size (fiber diameter) of these cellulose nanofibers varies depending on the type of cellulose nanofiber. Furthermore, the fiber diameter is selected to be within a range that is suitable in terms of thickening effect, long-term stability, color development, etc., without hindering the properties of the various applications.

[0084] Materials containing cellulose fibers can include plants such as wood, bamboo, kenaf, hemp, jute, wood pulp, recycled paper, crystalline cellulose, agricultural waste, and recycled pulp; animals such as sea squirts; algae; and microorganisms.

[0085] Cellulose nanofibers are commercially available and can also be used. Examples of commercially available products include the product names "Leocrysta I-2AX," "CNF 03," and "CNF 04" (all manufactured by Daiichi Chemical Industry Co., Ltd.), "ELLEX-S" (manufactured by Daio Paper Corporation), and "nanoforest-S" (manufactured by Chuetsu Pulp & Paper Co., Ltd.).

[0086] [Method for producing dyed carrier particles] When resin particles are used as carrier particles, the resin particles can be produced by conventionally known methods such as emulsion polymerization, miniemulsion polymerization, seed polymerization, and phase inversion emulsification. Methods for dyeing the resin particles include polymerizing a monomer mixture in which compounds represented by general formulas (1), (2), and (3) are dissolved to form resin particles, and adding compounds represented by general formulas (1), (2), and (3) to the resin particles and heating them.

[0087] When using cellulose nanofibers as carrier particles, the dyeing method for cellulose nanofibers involves contacting the cellulose nanofibers with compounds represented by general formulas (1), (2), and (3) in an aqueous medium. Subsequently, heating or oxidation treatment is performed as needed, and then the medium is removed by distillation to obtain dyed cellulose nanofibers.

[0088] [Medium] In this embodiment, the "medium" is selected according to the use and purpose of the ink and is not particularly limited, but means water or an organic solvent. When an organic solvent is used as the medium, the type of organic solvent is selected according to the purpose and use of the ink and is not particularly limited.

[0089] Examples of organic solvents include alcohols such as methanol, ethanol, isopropanol, butanol, 2-methyl-2-butanol, 3-pentanol, benzyl alcohol, and cyclohexanol; glycols such as methyl cellosolve, diethylene glycol, and diethylene glycol monobutyl ether; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; esters such as ethyl acetate, butyl acetate, and cellosolve acetate; aliphatic hydrocarbons such as octane, petroleum ether, and cyclohexane; aromatic hydrocarbons such as toluene and xylene; ethers such as diethyl ether, dimethyl glycol, trioxane, and tetrahydrofuran; acetals such as diethyl acetal; organic acids such as formic acid, acetic acid, and propionic acid; and sulfur or nitrogen-containing organic compounds such as monoethanolamine, pyridine, dimethyl sulfoxide, and dimethylformamide.

[0090] Furthermore, polymerizable monomers can also be used as organic solvents. Examples of polymerizable monomers include addition polymerizable monomers and condensate polymerizable monomers, with addition polymerizable monomers being preferred. Specifically, polymerizable monomers include styrene monomers such as styrene, methylstyrene, and ethylstyrene; acrylate monomers such as methyl acrylate, ethyl acrylate, behenyl acrylate, 2-ethylhexyl acrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, acrylonitrile, and acrylamide; methacrylate monomers such as methyl methacrylate, ethyl methacrylate, diethylaminoethyl methacrylate, methacrylonitrile, and methacrylateamide; ethylene, p Examples include olefin monomers such as polypropylene, butylene, butadiene, isoprene, isobutylene, and cyclohexene; halogenated vinyl monomers such as vinyl chloride, vinylidene chloride, vinyl bromide, and vinyl iodide; vinyl ester monomers such as vinyl acetate, vinyl propionate, and vinyl benzoate; vinyl ether monomers such as vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether; and vinyl ketone monomers such as vinyl methyl ketone, vinyl hexyl ketone, and methyl isopropenyl ketone. These may be used individually or in combination of two or more as needed.

[0091] In inks, the content of the medium is selected according to the purpose and application of the ink, and is not particularly limited.

[0092] The medium is preferably an aqueous medium containing at least water. The aqueous medium may also contain a water-soluble organic solvent in addition to water. Deionized water or ion-exchanged water is preferred as the water.

[0093] The water content in the ink is preferably 50.0% by mass or more and 95.0% by mass or less, based on the total mass of the ink. Furthermore, the water-soluble organic solvent content in the ink is preferably 2.0% by mass or more and 40.0% by mass or less, based on the total mass of the ink. As the water-soluble organic solvent, those commonly used in inks can be used. Examples include alcohols, (poly)alkylene glycols, glycol ethers, nitrogen-containing compounds, sulfur-containing compounds, etc. The water-soluble organic solvent content in the ink can be appropriately selected and is not particularly limited. The water-soluble organic solvent may be used alone or in combination of two or more types.

[0094] [Dispersant] When using an aqueous medium, it is preferable to use a dispersant to obtain good dispersion stability of the carrier particles dyed with the compounds represented by general formulas (1), (2), and (3) in the aqueous medium. The dispersant is not particularly limited, but ionic surfactants, nonionic surfactants, polymeric surfactants, etc., can be used.

[0095] Examples of ionic surfactants include aliphatic monocarboxylates, polyoxyethylene alkyl ether carboxylates; N-acyl sarcosine salts, N-acyl glutamate salts, dialkyl sulfosuccinates; alkanesulfonates, alpha-olefin sulfonates, linear or branched alkylbenzene sulfonates, naphthalene sulfonate formaldehyde condensates, alkylnaphthalene sulfonates; N-methyl-N-acyl taurate salts; alkyl sulfates, polyoxyethylene alkyl ether sulfates, oil sulfates; alkyl phosphates, polyoxyethylene alkyl ethers Examples include anionic surfactants such as phosphates and polyoxyethylene alkylphenyl ether phosphates; cationic surfactants such as alkylamine salts, alkyltrimethylammonium chloride, bromide, or iodide, dialkyldimethylammonium chloride, bromide, or iodide, alkylbenzalkonium chloride, and alkylpyridinium chloride; and amphoteric surfactants such as alkylbetaine, fatty acid amidopropyl betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, alkyl or dialkyldiethylenetriaminoacetic acid, and alkylamine oxide.

[0096] Examples of nonionic surfactants include glycerin fatty acid esters, sorbitan fatty acid esters, sucrose fatty acid esters; polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene polyoxypropylene glycol; fatty acid polyethylene glycol, fatty acid polyoxyethylene sorbitan, fatty acid alkanolamide, etc.

[0097] Examples of polymeric surfactants include anionic polymers such as polyacrylates, styrene-acrylic acid copolymers, vinylnaphthalene-acrylic acid copolymers, styrene-maleic acid copolymers, vinylnaphthalene-maleic acid copolymers, and polyphosphates; and nonionic polymers such as polyvinyl alcohol, polyvinylpyrrolidone, and polyalkylene glycols.

[0098] Examples of commercially available dispersants include styrene-based resin dispersants such as X-200, X-1, X-205, X-220 (all manufactured by Seikoh PMC Co., Ltd.) and Nopco Spers 6100 (manufactured by Sunopco Co., Ltd.), acrylic-based resin dispersants such as BYK-190, BYK-187, BYK-191, BYK-194N, BYK-199, BYKJET-9171 (all manufactured by Bic Chemie Co., Ltd.) and Aron A-6114 (all manufactured by Toagosei Co., Ltd.), and urethane-based resin dispersants such as BYK-184, BYK-182, BYK-183, BYK-185 (all manufactured by Bic Chemie Co., Ltd.) and TEGO Disperse 710 (all manufactured by Evonic Tego Chemi Co., Ltd.).

[0099] Among these, BYK-190, BYK-187, BYK-191, BYK-194N, BYK-199, and BYKJET-9171 are preferred, and BYK-190 and BYKJET-9171 are more preferred.

[0100] The amount of dispersant in the ink is selected as appropriate and is not particularly limited. The amount of dispersant in the ink (mass%) is preferably 0.1% by mass or more and 20.0% by mass or less, and more preferably 0.5% by mass or more and 15.0% by mass or less, based on the total mass of the ink.

[0101] [Additives] The following additives may be added to the ink as appropriate, to the extent that they do not impair the properties for various applications: Polyhydric alcohols such as trimethylolpropane and trimethylolethane; Urea derivatives such as urea and ethylene urea; Water-soluble resins and undyed resin particles; pH adjusters, rust inhibitors, preservatives, fungicides, antioxidants, reduction inhibitors, evaporation accelerators, lubricants, wetting agents, UV absorbers, defoamers, leveling agents, chelating agents, and cellulose nanofibers.

[0102] Examples of UV absorbers include benzophenone-based, benzotriazole-based, cyanoacrylate-based, and triazine-based UV absorbers.

[0103] Examples of commercially available UV absorbers include Tinuvin P, Tinuvin 326, Tinuvin 571, Tinuvin 360 (all manufactured by BASF), and ADEKA stab LA-24, LA-29, LA-31RG, LA-32, LA-36, LA-46, LA-F70, and 1413 (all manufactured by ADEKA Corporation). Among these, ADEKA stab LA-29, LA-32, LA-36, and LA-46 are preferred, and ADEKA stab LA-29, LA-32, and LA-36 are particularly preferred.

[0104] Examples of antioxidants include phenolic compounds.

[0105] Examples of commercially available antioxidants include ADEKA STAB AO-20, AO-30, AO-40, AO-50, AO-50F, AO-60, AO-60G, AO-80, and AO-330 (all manufactured by ADEKA Corporation).

[0106] [Ink Properties] It is preferable to use an ink with appropriately controlled surface tension and viscosity according to its intended use. For example, when used as an inkjet ink, the following is preferable.

[0107] The surface tension of the ink at 25°C is preferably 10 mN / m or more and 60 mN / m or less, more preferably 20 mN / m or more and 60 mN / m or less, and particularly preferably 30 mN / m or more and 50 mN / m or less.

[0108] Furthermore, the viscosity of the ink at 25°C is preferably 1.0 mPa·s or more and 10 mPa·s or less, and more preferably 1.0 mPa·s or more and 5 mPa·s or less.

[0109] [Method for producing the ink] The ink according to this embodiment can be produced as follows.

[0110] Carrier particles dyed with compounds represented by general formulas (1), (2), and (3) are prepared according to the method described above. The prepared carrier particles dyed with compounds represented by general formulas (1), (2), and (3), along with other colorants, emulsifiers, resins, etc. as needed, are gradually added to a medium selected according to the application while stirring, and thoroughly mixed with the medium. Furthermore, by applying mechanical shear force using a disperser to stably dissolve or finely disperse the mixture, the ink of the present invention can be obtained.

[0111] [Disperser] The disperser used to disperse each component into the medium is not particularly limited, but media-type dispersers such as rotary shear homogenizers, ball mills, sand mills, and attritors, as well as high-pressure opposing impact dispersers, can be used.

[0112] [Ink Applications] The ink according to this embodiment is suitable as an ink for oil-based writing instruments, water-based writing instruments, inkjet ink, textile printing ink, printing ink, and paint ink. Among these, it is preferable to use it as an ink for oil-based writing instruments, water-based writing instruments, and inkjet ink. The following describes examples of applications of the ink according to this embodiment. For items not specifically described, the contents described for the ink according to this embodiment apply as is.

[0113] [Ink for Oil-Based Writing Instruments] Ink for oil-based writing instruments comprises carrier particles dyed with the compounds represented by the general formulas (1), (2), and (3) described above, and an oil-based medium. As the oil-based medium, an organic solvent from among the aforementioned mediums can be used. Among these, the oil-based medium preferably contains alcohol or glycol ether. Furthermore, it is preferable that the medium does not contain water. In addition to these, it is preferable that the ink for oil-based writing instruments contains a resin that is dissolved in the medium. The content of carrier particles dyed with the compounds represented by the general formulas (1), (2), and (3) is appropriately selected depending on the application and is not particularly limited.

[0114] [Variables containing alcohol or glycol ether] Examples of alcohols include alkyl monoalcohols without substituents such as ethanol, isopropanol, n-butanol, isobutanol, tert-butanol, sec-butanol, 2-methyl-2-butanol, 3-pentanol, octanol, and cyclohexanol; alkyl monoalcohols with substituents such as 2-phenoxyethanol and 3-methyl-3-methoxy-1-butanol; alkyl polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, 3-methyl-1,3-butanediol, and 1,3-butanediol; and aromatic alcohols such as benzyl alcohol. Examples of substituents in alkyl monoalcohols with substituents include alkoxy groups and aryloxy groups.

[0115] In addition, while monoalcohol monoethers also exist as glycol ethers, these are listed as alcohols. Examples of diethers are given below: ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dipropylene glycol, ethylene glycol diethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, etc.

[0116] Furthermore, in addition to alcohols and glycol ethers, the medium may also contain water; and ester-based solvents such as 3-methyl-3-methoxybutyl acetate, butyl acetate, and methyl propionate.

[0117] The amount of writing medium used is not particularly limited and can be selected appropriately depending on the type of writing instrument, such as ballpoint pens, felt-tip pens, or marking pens.

[0118] [Resin present in a dissolved state in the medium] It is preferable to include a resin present in a dissolved state in the medium in order to adjust the viscosity of the ink and improve its abrasion resistance.

[0119] The resin used is determined according to the purpose and application of the ink and is not particularly limited, but examples include butyral resin, ketone resin, polyvinylpyrrolidone resin, styrene resin, styrene-acrylic resin, styrene-maleic acid resin, terpene resin, acrylic resin, polyvinyl acetal resin, polyvinyl butyral resin, terpene phenol resin, rosin-modified maleic acid resin, rosin-phenol resin, maleic acid resin, phenol resin, xylene resin, urea resin, polyamide resin, phenoxy resin, and cellulose-based resins. Butyral resin and ketone resin are preferably used to produce a writing experience that does not cause smudging.

[0120] Butyral resin and ketone resin may be commercially available products. Examples of commercially available ketone resins include the low-polymerization type products "Eslec BL-1," "BL-2," and "BL-10," and the high-polymerization type products "BH-3," "BH-6," "BX-1," "BX-5," and "BH-S" (all manufactured by Sekisui Chemical Co., Ltd.).

[0121] Furthermore, commercially available ketone resins include, for example, the product name "Ketone Resin K-90" (manufactured by Arakawa Chemical Industries, Ltd.), and the product names "Hi-Luck 901," "Hi-Luck 110H," and "Hi-Luck 111" (all manufactured by Hitachi Chemical Co., Ltd.).

[0122] By incorporating these resins into the ink, viscosity can be easily adjusted, pen tip wear can be prevented, and a consistently good writing experience can be achieved. Furthermore, because film formation can be moderately suppressed, ink solidification can be inhibited even if the pen tip is exposed for an extended period, thus suppressing the "skimming phenomenon" at the start of writing.

[0123] The content of these resins is selected as appropriate and is not particularly limited.

[0124] [Water-based writing instrument ink] Water-based writing instrument ink comprises carrier particles dyed with the compounds represented by the general formulas (1), (2), and (3) described above, and an aqueous medium. Water-based writing instrument ink preferably further contains a dispersant. Water-based writing instrument ink may also contain a water-soluble resin as needed. The content of carrier particles dyed with the compounds represented by the general formulas (1), (2), and (3) is not particularly limited and can be appropriately selected depending on the application.

[0125] [Inkjet Ink] Inkjet ink comprises carrier particles dyed with the compounds represented by the general formulas (1), (2), and (3) described above, and a medium. It is preferable to use an aqueous medium among the aforementioned mediums. It is also preferable that the inkjet ink further contains a dispersant. The content of carrier particles dyed with the compounds represented by the general formulas (1), (2), and (3) is appropriately selected depending on the application and is not particularly limited.

[0126] [Inkjet Recording Method] The inkjet ink according to this embodiment can be applied to an inkjet recording method in which an image is recorded on a recording medium by ejecting ink from an inkjet recording head. Methods for ejecting the ink include methods that impart mechanical energy to the ink and methods that impart thermal energy to the ink. Aside from using the ink according to this embodiment, the steps of the inkjet recording method can be those of known origin.

[0127] Any recording medium can be used as the recording medium to be recorded using the inkjet ink according to this embodiment. Recording media with ink absorption properties can be used, such as recording media without a coating layer, such as plain paper, and recording media with a coating layer, such as glossy paper or matte paper. In addition, recording media with low ink absorption or no ink absorption properties, such as printing paper, coated paper, resin sheets, and resin films, can be used.

[0128] [Ink for Textile Printing] The ink for textile printing comprises carrier particles dyed with the compounds represented by the general formulas (1), (2), and (3) described above, and a medium. It is preferable to use an aqueous medium among the aforementioned mediums. The ink for textile printing further preferably contains a dispersant. The content of carrier particles dyed with the compounds represented by the general formulas (1), (2), and (3) is appropriately selected depending on the application and is not particularly limited.

[0129] [Printing Method] The printing ink according to this embodiment can be applied to known printing methods. In particular, it can be applied to direct printing recording methods.

[0130] The following describes a direct printing method as an example of a recording method using the printing ink according to this embodiment, but the method is not limited to this method.

[0131] The direct printing method is a recording method that involves a process of directly applying ink to fabric using an inkjet method to record an image, without using an intermediate transfer medium.

[0132] For inkjet-based recording heads, piezo-type and thermal-type recording heads can be used.

[0133] The fabric to which the ink has been applied is subjected to a heat and pressure treatment to fix the image onto the fabric. The heat and pressure treatment time is preferably 30 seconds to 180 seconds. The heating temperature in this process is not particularly limited, but is preferably 180°C to 220°C, more preferably 185°C to 205°C, and particularly preferably 190°C to 200°C.

[0134] When using the ink according to this embodiment as a printing ink, the fabric that can be printed is not particularly limited as long as it is dyeable, but examples include fabrics made of fibers containing polyester, acetate, or triacetate. The fabric may be woven, knitted, or nonwoven. Fabrics made of cotton, silk, linen, polyurethane, acrylic, nylon, wool, and rayon fibers, or fabrics made by combining two or more of these fibers, can also be used. In addition, objects having three-dimensional shapes such as sheets, spheres, or rectangular prisms, such as polyester-coated mugs, may also be used.

[0135] The thickness of the yarn that makes up the fabric is preferably in the range of 10 denier to 100 denier. The thickness of the fibers that make up the yarn is not particularly limited, but is preferably 1 denier or less.

[0136] <Second Embodiment> As a result of diligent research to solve the above problems, the present inventors have found that the following configuration can provide an ink with high optical density and excellent color development stability and lightfastness during heat pressing.

[0137] The ink according to this embodiment contains an aqueous medium, a dispersant, a compound represented by general formula (1), a compound represented by general formula (2), and a compound represented by general formula (3).

[0138] When compounds represented by the above general formulas (1), (2), and (3) are used, inks with high optical density and excellent color development stability and lightfastness during hot pressing can be obtained. The mechanism contributing to this color development stability is not clearly understood, but the inventors speculate as follows.

[0139] The compounds represented by general formulas (1), (2), and (3) are structurally of similar size, and overlapping occurs due to π-π stacking interactions or hydrogen bonding of the benzene rings in each compound. We believe that the aforementioned effects are produced when the three compounds are stabilized by this overlap.

[0140] Furthermore, the ink according to this embodiment can be used for a wide range of textile applications, including dyeing polyester fibers, sports apparel made by weaving polyester with polyurethane, and high-end dresses with processed fiber shapes.

[0141] The components of the ink according to this embodiment will be described in detail. Note that the compounds represented by general formulas (1), (2), and (3), the additives, and the disperser used to disperse each component in the aqueous medium can be the same as those described in the first embodiment, so their description will be omitted. Furthermore, the ink according to this embodiment can be used as an inkjet ink (aqueous ink) containing an aqueous medium. The composition of the inkjet ink containing an aqueous medium, the physical properties of the ink, and the method of manufacturing the ink can also be adjusted in the same way as those described in the first embodiment, so their description will be omitted.

[0142] [Dispersant] In the ink according to this embodiment, a dispersant is used to obtain good dispersion stability in an aqueous medium for the compounds represented by general formulas (1), (2), and (3). The dispersant is not particularly limited, but the same as that described in the first embodiment above can be used.

[0143] [Aqueous Medium] The ink according to this embodiment is an aqueous ink containing at least water as the aqueous medium. The aqueous medium is not particularly limited, but the same as that described in the first embodiment above can be used.

[0144] [Recording Method] The ink according to this embodiment can be applied to a sublimation transfer method or a direct print method of recording.

[0145] The following describes a sublimation transfer method as an example of a recording method using the ink according to this embodiment, but the method is not limited to this method.

[0146] The sublimation transfer recording method comprises (1) a step of applying ink to an intermediate transfer medium to record an image, and (2) a transfer step of transferring the image from the intermediate transfer medium to a fabric.

[0147] (Step of recording an image on an intermediate transfer medium) In the step of recording an image on transfer paper, the ink according to this embodiment is applied to the transfer paper, which is the intermediate transfer medium, by an inkjet method. The transfer paper is not particularly limited, but the use of sublimation transfer printing paper is preferred.

[0148] For inkjet printing, recording heads of the piezo or thermal type can be used.

[0149] (Process of transferring the image to the fabric) The transfer paper on which the image has been recorded, after going through the image recording process, is placed on top of the fabric which is the recording medium, and is subjected to heating and pressing treatment with a heating and pressing device such as a heat press. As a result, the image is transferred to the fabric and the image can be recorded on the fabric. The same type of fabric as described in the first embodiment above can be used. In particular, with polyester and polyurethane mixed materials that have been widely used in sportswear in recent years, conventional sublimation dyes tended to cause variations in color development depending on the heat pressing temperature, but with the ink according to this embodiment, dyed products with excellent color development stability during heat pressing can be obtained. The heating and pressing treatment time is preferably 30 seconds or more and 180 seconds or less. In addition, the lower limit of the heating temperature in this process is not particularly limited, but is preferably 180°C or more and 220°C or less, more preferably 185°C or more and 205°C or less, and particularly preferably 190°C or more and 200°C or less.

[0150] The hot pressing pressure in this process is not particularly limited, but is preferably 30 PSI or more and 120 PSI or less, and particularly preferably 40 PSI or more and 90 PSI or less.

[0151] Alternatively, a sublimation transfer machine that performs transfer under vacuum and at low temperatures (for example, product name "PSH-4230," manufactured by Europort Co., Ltd.) can also be used instead of a heat press.

[0152] <Third Embodiment> As a result of diligent research to solve the above problems, the inventors have found that color mixing and fading can be suppressed by the following configuration.

[0153] The thermal transfer recording sheet according to this embodiment comprises a substrate and a black colorant layer formed on the substrate. In the thermal transfer recording sheet, the black colorant layer contains a compound represented by general formula (1), a compound represented by general formula (2), and a compound represented by general formula (3).

[0154] As a result of their investigation, the inventors found that by using a combination of compounds represented by general formulas (1), (2), and (3), which each have problems when used individually as black colorants, color mixing and fading can be suppressed.

[0155] The mechanism by which the black colorant suppresses color mixing and fading caused by mixing compounds with different structures of different colors is not clearly understood, but the inventors speculate as follows.

[0156] Compounds represented by general formulas (1), (2), and (3) are structurally of similar size, and overlapping occurs between the compounds due to π-π stacking interactions or hydrogen bonding of the benzene rings in each compound. It is believed that the aforementioned effect is achieved through stabilization by this overlap. Furthermore, color fading can be evaluated by the lightfastness of the image recording. For example, the presence or absence of color fading can be evaluated by a lightfastness test in which light is irradiated onto the image recording using a xenon test apparatus and the color difference ΔE before and after irradiation (before and after exposure) is calculated.

[0157] The structure of the thermal transfer recording sheet will be described in detail below. Note that the compounds represented by general formulas (1), (2), and (3) used in the thermal transfer recording sheet are the same as those described in the first embodiment, so their explanation will be omitted.

[0158] The thermal transfer recording sheet preferably has, in addition to the black colorant layer, a yellow colorant layer, a magenta colorant layer, and a cyan colorant layer. Furthermore, it is more preferable that the yellow colorant layer, the magenta colorant layer, the cyan colorant layer, and the black colorant layer are formed sequentially on the substrate.

[0159] [Substrate] The substrate of the thermal transfer recording sheet preferably supports at least the four colorant layers described above. The substrate is not particularly limited, and any substrate with appropriate heat resistance and strength that is conventionally known in the field of thermal transfer recording sheets can be used.

[0160] Examples of suitable base materials include polyethylene terephthalate film, polyethylene naphthalate film, polycarbonate film, polyimide film, polyamide film, aramid film, polystyrene film, 1,4-polycyclohexylenedimethylene terephthalate film, polysulfone film, polypropylene film, polyphenylene sulfide film, polyvinyl alcohol film, cellophane film, cellulose derivative film, polyethylene film, polyvinyl chloride film, nylon film, condenser paper, and paraffin paper. Among these, polyethylene terephthalate film is preferred as a base material from the viewpoint of mechanical strength, solvent resistance, and economic efficiency.

[0161] - Substrate thickness The substrate thickness can be 0.5 μm or more and 50 μm or less, but from the viewpoint of transferability, it is preferable to have a thickness of 3 μm or more and 10 μm or less.

[0162] When applying a colorant composition (ink) containing dyes to form each colorant layer on an adhesive-treated substrate, the wettability and adhesiveness of the coating liquid (colorant composition) may be insufficient. Therefore, it is preferable to apply an adhesive treatment to the coated surface of the substrate as needed.

[0163] The bonding treatment is not particularly limited, and methods known in the field of thermal transfer recording sheets can be used. Examples of bonding treatments include ozone treatment, corona discharge treatment, ultraviolet treatment, plasma treatment, low-temperature plasma treatment, primer treatment, and chemical treatment. Two or more of these treatments may also be combined.

[0164] Furthermore, for the bonding treatment of the substrate, a method of coating an adhesive layer onto the substrate may be used. This adhesive layer is not particularly limited, and adhesive layers known in the field of thermal transfer recording sheets can be used. Examples of materials used for the adhesive layer include organic materials such as polyester resin, polystyrene resin, polyacrylic acid ester resin, polyamide resin, polyether resin, polyvinyl acetate resin, polyethylene resin, polypropylene resin, polyvinyl chloride resin, polyvinyl alcohol resin, and polyvinyl butyral resin, as well as inorganic fine particles such as silica, alumina, magnesium carbonate, magnesium oxide, and titanium oxide.

[0165] [Heat-resistant slippery layer] For thermal transfer recording sheets, it is preferable to provide a heat-resistant slippery layer on the side of the substrate opposite to the side with the colorant layer, in order to improve heat resistance and thermal head movement.

[0166] The heat-resistant lubricating layer consists of a layer containing a heat-resistant resin. The heat-resistant resin is not particularly limited, and for example, the following resins can be used: polyvinyl butyral resin, polyvinyl acetal resin, polyester resin, polyether resin, polybutadiene resin, vinyl chloride-vinyl acetate copolymer resin, styrene-butadiene copolymer resin, polyurethane acrylate, polyester acrylate, polyimide resin, polycarbonate resin, etc.

[0167] Furthermore, the heat-resistant lubricating layer may contain additives such as crosslinking agents, mold release agents, lubricants, and lubrication agents. Examples of the lubricants include amino-modified silicone compounds and carboxy-modified silicone compounds. Examples of lubrication agents include fine particles such as silica, which are heat-resistant fine particles.

[0168] The heat-resistant lubricating layer can be formed by applying a heat-resistant lubricating layer coating solution, prepared by adding the above-mentioned heat-resistant resin and additives to a solvent, dissolving or dispersing them, to a substrate and drying it. The method of applying the heat-resistant lubricating layer coating solution is not particularly limited, and for example, methods using a bar coater, gravure coater, reverse roll coater, rod coater, or air doctor coater can be used. Among these, the coating method using a gravure coater, which allows for easy adjustment of the film thickness, is preferred.

[0169] From the viewpoint of transferability, it is preferable to apply the heat-resistant lubricating layer coating liquid to the substrate in such an amount that the thickness of the heat-resistant lubricating layer after drying is in the range of 0.1 μm to 5 μm.

[0170] [Protective Layer] The thermal transfer recording sheet may have one or two transferable protective layers on the substrate, arranged in order with the colorant layer described later, to protect the image surface after image formation. Alternatively, this protective layer may be formed on a different sheet (substrate) from the colorant layer. In this case, the thermal transfer recording sheet according to this embodiment will include a sheet having a substrate and a colorant layer (colorant layer sheet) and a sheet having a substrate and a protective layer (protective layer sheet).

[0171] The protective layer can be formed by applying and drying the respective layer compositions onto the substrate. The method for applying the layer compositions onto the substrate is not particularly limited and includes methods using bar coaters, gravure coaters, reverse roll coaters, rod coaters, air doctor coaters, etc. Among these, a coating method using a gravure coater, which allows for easy adjustment of the film thickness, is preferred.

[0172] Furthermore, the drying conditions after applying each layer composition are not particularly limited as long as sufficient drying can be achieved. For example, drying can be performed at a temperature range of 50°C to 120°C for 1 second to 5 minutes.

[0173] The binder resin used in the protective layer is not particularly limited, but suitable examples include acrylic resins such as polystyrene, polymethyl methacrylate, and polyethyl acrylate; styrene resins such as poly-α-methylstyrene; vinyl resins such as polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, and polyvinyl acetal; and synthetic resins such as polyamide resin, epoxy resin, polyurethane resin, petroleum resin, ionomer, ethylene-acrylic acid copolymer, and ethylene-acrylic acid ester copolymer.

[0174] The thickness of the protective layer is preferably in the range of 0.1 μm to 5 μm.

[0175] Furthermore, it is more preferable to have a release layer with a thickness of 0.1 μm to 1.5 μm beneath the black colorant layer containing the aforementioned compound, which contains an acrylic resin such as polymethyl methacrylate or polyethyl acrylate to facilitate peeling from the sheet.

[0176] The above-mentioned release layer is formed on the aforementioned substrate.

[0177] [Colorant layer] In a thermal transfer recording sheet, the black colorant layer contains the compounds represented by the general formulas (1), (2), and (3) described above as black colorants.

[0178] Furthermore, the three compounds mentioned above can be used in combination with other yellow, magenta, and cyan colorants, to the extent that they do not interfere with the effects of this embodiment. The other yellow, magenta, and cyan colorants are those used in the field of thermal transfer recording sheets and are not particularly limited as long as they are heat-transferable.

[0179] Furthermore, the melting point of the compounds represented by general formulas (1), (2), and (3) is preferably 40°C to 200°C from the viewpoint of transferability and storage properties. More preferably, it is 50°C to 180°C, and particularly preferably, 60°C to 150°C.

[0180] The blending ratio of the compound represented by general formula (1), the compound represented by general formula (2), and the compound represented by general formula (3) is not particularly limited. Preferably, the blending ratio (mass ratio) of the compound represented by general formula (1), the compound represented by general formula (2), and the compound represented by general formula (3) is as follows: For every 10 parts by mass of the compound represented by general formula (1), it is preferable that the compound represented by general formula (2) is 3 to 9 parts by mass, and the compound represented by general formula (3) is 1 to 6 parts by mass. It is particularly preferable that the compound represented by general formula (2) is 4 to 8 parts by mass, and the compound represented by general formula (3) is 2 to 5 parts by mass. It is even more preferable that the compound represented by general formula (2) is 4 to 6 parts by mass, and the compound represented by general formula (3) is 2 to 4 parts by mass. Within this range, it is easier to obtain a thermal transfer recording sheet in which color mixing and fading are suppressed in the formulation of the three pigments used in the black pigment layer: yellow pigment, magenta pigment, and cyan pigment.

[0181] (Components in the colorant layer) The following describes each component in the colorant layer other than the three compounds mentioned above.

[0182] (i) Other colorant compounds: The yellow colorant used in the yellow colorant layer, the magenta colorant used in the magenta colorant layer, and the cyan colorant used in the cyan colorant layer are not particularly limited as they are used in the field of thermal transfer recording sheets and are transferred by heat. In addition, one type of colorant compound for each color may be used, or two or more types may be used in combination.

[0183] (ii) The binder resin that can be used in each colorant layer of the thermal transfer recording sheet is not particularly limited, and various resins can be used. Among these, it is preferable to use the following water-soluble resins and organic solvent-soluble resins.

[0184] Water-soluble resins: Cellulose resins, polyacrylic acid resins, starch resins, and epoxy resins, etc.

[0185] Organic solvent-soluble resins: polyacrylate resins, polymethacrylate resins, polystyrene resins, polycarbonate resins, polyethersulfone resins, polyvinyl butyral resins, ethylcellulose resins, acetylcellulose resins, polyester resins, AS resins, and phenoxy resins, etc.

[0186] These binding resins may be used individually, or two or more may be used in combination as needed.

[0187] (iii) Surfactants may be added to each color layer of the thermal transfer recording sheet to provide sufficient lubricity when the thermal head is heated (during image recording). Examples of surfactants that can be added to each color layer include cationic surfactants, anionic surfactants, and nonionic surfactants.

[0188] Examples of the cationic surfactants mentioned above include dodecylammonium chloride, dodecylammonium bromide, dodecyltrimethylammonium bromide, dodecylpyridinium chloride, dodecylpyridinium bromide, and hexadecyltrimethylammonium bromide.

[0189] Examples of the above-mentioned anionic surfactants include fatty acid soaps such as sodium stearate and sodium dodecanoate, sodium dodecyl sulfate, sodium dodecylbenzene sulfate, and sodium lauryl sulfate.

[0190] Examples of the nonionic surfactants mentioned above include dodecyl polyoxyethylene ether, hexadecyl polyoxyethylene ether, nonylphenyl polyoxyethylene ether, lauryl polyoxyethylene ether, sorbitan monooleate polyoxyethylene ether, and monodecanoyl sucrose.

[0191] (iv) Wax may be added to each color layer of the wax thermal transfer recording sheet to provide sufficient lubricity when the thermal head is not heated. Examples of waxes that can be added to each color layer include, but are not limited to, polyethylene wax, paraffin wax, and fatty acid ester wax.

[0192] (v) Other additives In addition to the components described above, UV absorbers, preservatives, antioxidants, antistatic agents, viscosity modifiers, etc. may be added to each colorant layer of the thermal transfer recording sheet as needed.

[0193] Examples of UV absorbers include benzophenone-based, benzotriazole-based, cyanoacrylate-based, and triazine-based UV absorbers.

[0194] Examples of commercially available UV absorbers include Tinuvin P, Tinuvin 326, Tinuvin 571, Tinuvin 360 (all manufactured by BASF), and ADEKA stab LA-24, LA-29, LA-31RG, LA-32, LA-36, LA-46, LA-F70, and 1413 (all manufactured by ADEKA Corporation).

[0195] Preferably, the Adeka stubs are LA-29, LA-32, LA-36, and LA-46, and particularly preferably, the Adeka stubs are LA-29, LA-32, and LA-36.

[0196] Examples of antioxidants include phenolic compounds.

[0197] Examples of commercially available antioxidants include ADEKA STUB AO-20, AO-30, AO-40, AO-50, AO-50F, AO-60, AO-60G, AO-80, and AO-330 (all manufactured by ADEKA Corporation).

[0198] (vi) The medium that can be used to prepare each colorant composition for the thermal transfer recording sheet is not particularly limited, but examples include water and organic solvents. The following are examples of organic solvents that can be preferably used: Alcohols such as methanol, ethanol, isopropanol, and isobutanol; cellosolves such as methyl cellosolve and ethyl cellosolve; aromatic hydrocarbons such as toluene, xylene, and chlorobenzene; esters such as ethyl acetate and butyl acetate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; halogenated hydrocarbons such as methylene chloride, chloroform, and trichloroethylene; ethers such as tetrahydrofuran and dioxane; N,N-dimethylformamide, N-methylpyrrolidone, etc. These organic solvents may be used alone or in combination of two or more as needed. Water and organic solvents can also be used in combination.

[0199] (Composition of the colorant composition for forming the colorant layer) ・Colorant content (amount used) From the viewpoint of preservation of the sheet, the amount of each colorant (yellow colorant, magenta colorant, cyan colorant, or black colorant) used in each colorant composition is preferably 1 part by mass or more and 200 parts by mass or less in total per 100 parts by mass of the binder resin. From the viewpoint of dispersion of the colorant, it is more preferable that it be 50 parts by mass or more and 180 parts by mass or less per 100 parts by mass of the binder resin. When two or more types of colorants are used in mixture, the amount of the above colorants used refers to the total amount of parts by mass of each colorant. For example, when the compounds of the above general formulas (1), (2), and (3) and an existing colorant are used in combination as the black colorant, the amount of the above colorants used refers to the total number of parts by mass of these colorants.

[0200] • Content (amount used) of other ingredients: The amount used of other ingredients (additives) can be set as appropriate and is not particularly limited.

[0201] [Method for manufacturing thermal transfer recording sheets] There are no particular limitations on the method for manufacturing thermal transfer recording sheets, but they can be manufactured as follows, for example. As an example, we will describe the black colorant layer.

[0202] First, gradually add the compounds represented by general formulas (1), (2), and (3) (colorants), and optionally a binder resin, surfactant, and wax, to a medium (e.g., an organic solvent) while stirring, allowing them to fully blend into the medium.

[0203] In this process, mechanical shear force is applied using a disperser to stably dissolve or disperse these components into fine particles in the medium, thereby producing a colorant composition (ink). By applying and drying this colorant composition onto a base film, which is a substrate, the desired colorant layer can be produced.

[0204] The disperser used in preparing the colorant composition is not particularly limited, but for example, media-type dispersers such as rotary shear homogenizers, ball mills, sand mills, and attritors, as well as high-pressure opposing impact dispersers, can be used.

[0205] In thermal transfer recording sheets, each colorant layer is formed sequentially on the substrate. For example, on a substrate (substrate sheet), a yellow colorant layer, a magenta colorant layer, a cyan colorant layer, a black colorant layer, and a protective layer can be repeatedly formed along the direction of movement of the substrate. When a thermal transfer sheet with colorant layers in this order is used, a yellow image is formed first, followed by a magenta image, a cyan image, and then a black image, in a series of image formations to form a single full-color image. Finally, a protective layer is formed, and this series of image formations is repeated.

[0206] The colorant layer can be formed by applying and drying a colorant composition for each colorant layer formation onto the substrate. The method for applying the colorant composition for colorant layer formation onto the substrate is not particularly limited and includes methods using a bar coater, gravure coater, reverse roll coater, rod coater, air doctor coater, etc. Among these, the application method using a gravure coater, which allows for easy adjustment of the thickness of the colorant layer, is preferred.

[0207] Furthermore, the drying conditions after applying the colorant composition for forming each colorant layer are not particularly limited as long as sufficient drying can be achieved. For example, drying can be performed at a temperature of 50°C to 120°C for 1 second to 5 minutes.

[0208] By thoroughly drying each colorant composition, it becomes easier to prevent staining of the background and transfer of the colorant composition to the back of the fabric during winding. Furthermore, it becomes easier to prevent the transfer of the transferred colorant composition to a colorant layer of a different hue during rewinding.

[0209] From the viewpoint of transferability, it is preferable to apply the above-mentioned colorant composition in such a way that the thickness of the colorant layer after drying is in the range of 0.1 μm to 5 μm.

[0210] [Method for recording images on a thermal transfer recording sheet] A thermal transfer recording sheet is placed on top of a transfer target, such as an image receiving sheet having a colorant receiving layer on its surface. By heating the thermal transfer recording sheet using a heating method such as a thermal head, the colorant in the sheet is transferred to the image receiving sheet, thereby recording an image. If the thermal transfer recording sheet has the transferable protective layer described above, the protective layer portion of the sheet is placed on top of the image formed on the image receiving sheet. Then, by heating using a heating method such as a thermal head, the protective layer can be transferred (formed) onto the image.

[0211] The heating method for heating a thermal transfer recording sheet for image recording is not particularly limited, but in addition to the conventional method using a thermal head, infrared or laser light can also be used. Furthermore, an electrically conductive heat-generating film that generates heat by passing electricity through the base film of the substrate can be used as an electrically conductive dye transfer sheet.

[0212] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. Unless otherwise specified, "part" in this text refers to a mass-based unit.

[0213] <<Examples of the First Embodiment>> <Preparation and Evaluation of Inkjet Ink> [Examples 1-1 to 1-14 and Comparative Examples 1-1 to 1-7] [Compounds represented by general formulas (1), (2), and (3)] The compounds represented by the general formulas (1), (2), and (3) mentioned above were synthesized by known methods or were commercially available. The compounds represented by general formulas (1), (2), and (3) used in this embodiment are listed in Table 1-1.

[0214] Furthermore, the compounds obtained through synthesis were identified using a 1H nuclear magnetic resonance spectroscopy (1H-NMR) spectrometer (product name "AVANCE-600 NMR spectrometer," manufactured by BRUKER) and a MALDI-TOF / MS spectrometer (product name "MALDI-TOF / MS ultraFleXtreme," manufactured by BRUKER).

[0215] [Comparative Compounds] The following magenta-colored comparative compounds (1) and (3), and the cyan-colored comparative compound (2) were used as comparative compounds.

[0216]

[0217] [Preparation of aqueous dispersion of resin particles (A)] In a reaction vessel, 1,178 parts of water at 70°C were mixed with 466 parts of monomer (50% styrene, 47% acrylonitrile, 3% methacrylic acid), and a polymerization initiator (aqueous solution of 1.9 parts potassium persulfate and 659 parts water) was added dropwise over 60 minutes. The mixture was then stirred at 70°C for 30 minutes to obtain an aqueous dispersion of core resin particles.

[0218] Next, the aqueous dispersion of core resin particles was heated to 80°C, and 80 parts of monomer mixture (85% styrene, 15% methacrylic acid) and polymerization initiator (an aqueous solution of 0.1 parts potassium persulfate added to 133 parts water) were added dropwise over 10 minutes. The mixture was then stirred for another 120 minutes to synthesize resin particles (A) that would form a shell film (core-shell structure) on the core resin.

[0219] Next, an appropriate amount of 8 mol / L potassium hydroxide aqueous solution was added to the reaction vessel to adjust the pH of the liquid to 8.5. Furthermore, 29 parts of the compounds shown in Table 1-1 (the mixing ratio of each compound is as described in Table 1-1) in powder form (5% of the resin particles) and 29 parts of ethanol / butanol (8 / 2) were added, and the temperature was raised to 80°C. The mixture was then stirred for 2 hours. After removing the solvent under reduced pressure, an appropriate amount of 8 mol / L potassium hydroxide aqueous solution was added to the reaction vessel to adjust the pH of the liquid to 8.5. Water was added so that the resin particle content was 20% to obtain an aqueous dispersion of resin particles (A).

[0220] [Preparation of aqueous dispersion of resin particles (B)] Under a nitrogen atmosphere, 100 parts of methyl ethyl ketone at 78°C and 100 parts of monomer were added to a reaction vessel and mixed. A polymerization initiator (a mixture of 1 part azobisisobutyronitrile and 20 parts methyl ethyl ketone) was added dropwise over 2 hours. The monomer contained 30% styrene, 30% n-butyl acrylate, and 40% methacrylic acid. After further reaction for 2 hours, the mixture was cooled to 30°C, and 100 parts dimethylethanolamine and 100 parts water were added. Subsequently, the solvent was removed by distillation under reduced pressure to obtain resin particle solution (B).

[0221] Meanwhile, under a nitrogen atmosphere, an aqueous solution prepared by adding 1 part sodium bicarbonate and 1 part sodium lauryl sulfate to 178 parts water was heated to 80°C, and then 1 part potassium persulfate was added. To this, a solution prepared by adding 200 parts methyl methacrylate, 140 parts butyl acrylate, 5 parts glycidyl methacrylate, a total of 5 parts of the compounds shown in Table 1-1, and 6 parts sodium lauryl sulfate to 178 parts water was added dropwise over 2 hours. The mixing ratios of each compound shown in Table 1-1 are as described in Table 1-1. Subsequently, 119 parts of the resin particle solution (B) obtained above were added dropwise over 30 minutes, and then 35 parts of a 1% ammonium persulfate aqueous solution were added dropwise over 30 minutes. The reaction was carried out at 80°C for 2 hours to obtain an aqueous dispersion of resin particles (B) with a solid content of 40%.

[0222] [Preparation of aqueous dispersion of resin particles (C)] In the preparation of the aqueous dispersion of resin particles (B) described above, the compounds shown in Table 1-1 were changed, and 10 parts of ADEKA LA-36 (manufactured by ADEKA Corporation), an ultraviolet absorber, were further added, and the solution was changed to one that was added to 168 parts of water. Except for this, an aqueous dispersion of resin particles (C) with a solid content of 40% was obtained using the same method as for aqueous dispersion of resin particles (B).

[0223] [Ink Preparation] 50 parts of an aqueous dispersion of resin particles (A), (B), or (C), 10 parts of glycerin, 10 parts of triethylene glycol, 1 part of acetylenol E100 (manufactured by Kawaken Fine Chemicals), and 35 parts of water were mixed and stirred. Then, the mixture was pressure filtered through a 3.0 μm pore size microfilter (manufactured by Fujifilm) to prepare the inks listed in Table 1-1. The pH of each prepared ink was in the range of 8.5 to 9.0.

[0224] [Evaluation of Ink Storage Stability] The inks used in the examples and comparative examples were each placed in 100 mL sample bottles, sealed tightly, and stored at 10°C for one month. The presence or absence of aggregates and precipitates after storage was visually inspected and evaluated. The evaluation results are shown in Table 1-2. The evaluation criteria are as follows. In the evaluation, storage stability was judged to be good if "almost no aggregates and precipitates of the compound were observed" or "a small amount of aggregates and precipitates of the compound were observed". (Evaluation Criteria) A: Almost no aggregates and precipitates of the compound were observed B: A small amount of aggregates and precipitates of the compound were observed C: A considerable amount of aggregates and precipitates of the compound were observed

[0225] [Creation of Image Samples] Each of the prepared inks was filled into an ink cartridge, and a solid image with 100% duty cycle was recorded onto a recording medium using an inkjet recording device (product name "PIXUS Pro-10", manufactured by Canon) to obtain a black image sample (image recording). Photo paper (product name "Canon Photo Paper Glossy Pro [Platinum Grade] (model number: PT-201)", manufactured by Canon) was used as the recording medium.

[0226] [Evaluation of lightfastness of printed materials (image recordings)] Each obtained black image sample was placed in a xenon test apparatus (product name "Atlas Weatherometer Ci4000", manufactured by Toyo Seiki Seisakusho Co., Ltd.) and tested at an illuminance of 340 nm and 0.28 W / m². ２ The subjects were exposed for 24 hours under conditions of 40°C temperature and 50% relative humidity.

[0227] The colorimetric measurement of the reflectance density of black image samples before and after exposure was performed using a reflectance densitometer (product name "FD-7", manufactured by Konica Minolta).

[0228] The initial chromaticity before exposure was a ０ ＊ , b ０ ＊ , L ０ ＊ The chromaticity after exposure is set to a ＊ , b ＊ , L ＊ In this case, the color difference ΔE was defined and calculated as follows.

[0229]

[0230] The evaluation was then performed based on ΔE. The evaluation results are shown in Table 1-2. The evaluation criteria are as follows: In the evaluation, if ΔE after 24 hours was less than 7.00, it was judged that the light resistance was good. (Evaluation criteria) A: ΔE < 5.00 B: 5.00 ≤ ΔE < 7.00 C: 7.00 ≤ ΔE

[0231]

[0232]

[0233] As is clear from Tables 1-1 and 1-2 above, the inks using resin particles dyed with a combination of the compounds of general formulas (1), (2), and (3) described in the examples showed good storage stability and improved lightfastness of the printed materials. In contrast, the comparative inks using resin particles dyed with comparative compounds that have different structures from general formulas (1), (2), and (3) showed poor storage stability or lightfastness.

[0234] <Preparation and Evaluation of Oil-Based Writing Instrument Ink> [Example 1-15] To a mixed solution of 78 parts 1-phenoxy-2-propanol and 22 parts benzyl alcohol, 9 parts Elec BL-1 (manufactured by Sekisui Chemical Co., Ltd.) and 1 part polyvinylpyrrolidone resin K-90 (manufactured by Nippon Shokubai Co., Ltd.) were added as resins and heated to 70°C to dissolve. After cooling to room temperature, 10 parts of compound (1-4) represented by general formula (1), 10 parts of compound (2-2) represented by general formula (2), 10 parts of compound (3-4) represented by general formula (3), and 3 parts of Prysurf A208N were added as colorants. The mixed solution was dispersed for 3 hours using an attritor (manufactured by Mitsui Mining Co., Ltd.) to prepare oil-based writing instrument ink (1-1).

[0235] [Comparative Example 1-8] A comparative oil-based ink (1-1) for a writing instrument was prepared in the same manner as in Example 1-15, except that the coloring agent was changed to 10 parts of compound (1-4) represented by general formula (1), 10 parts of comparative compound (1), and 10 parts of compound (3-3) represented by general formula (3).

[0236] [Evaluation of Storage Stability of Oil-Based Writing Instrument Ink] 20 mL of each of the oil-based writing instrument inks obtained above was added to a 50 mL sample bottle, sealed, and left for one month under conditions of 60°C. After standing, the surface condition was observed under 20x magnification using a phase-contrast microscope (product name "BX53", manufactured by OLYMPUS Corporation). As a result of the observation, particle aggregation was observed in Comparative Examples 1-8, which did not use any of the compounds represented by general formulas (1), (2), and (3). On the other hand, aggregation was not observed in Example 1-15, which used all of the compounds represented by general formulas (1), (2), and (3). From this, it was confirmed that the storage stability was improved by using all of the compounds represented by general formulas (1), (2), and (3).

[0237] [Preparation of Oil-Based Writing Instruments and Evaluation of Lightfastness] The oil-based inks for writing instruments obtained above were each filled into polypropylene ink reservoirs with an inner diameter of 1.2 mm and a length of 140 mm. A ballpoint pen for evaluation testing was prepared, equipped with this ink reservoir and a phosphor bronze tip (ball diameter 0.7 mm). Using this ballpoint pen, a 2 cm square image sample was created on a recording medium with a constant writing pressure. Photographic paper (product name "Canon Photo Paper Glossy Pro [Platinum Grade] (model number: PT-201)", manufactured by Canon) was used as the recording medium.

[0238] The obtained image samples were placed in a xenon test apparatus (product name "Atlas Weatherometer Ci4000," manufactured by Toyo Seiki Seisakusho Co., Ltd.). After placement, the illuminance was set to 340 nm and 0.28 W / m². ２ The samples were exposed for 10 hours under the conditions of a black panel temperature of 40°C and relative humidity of 50%. Compared to Comparative Examples 1-8, which did not use any of the compounds represented by general formulas (1) to (3), Example 1-15, which used all of the compounds represented by general formulas (1) to (3), showed a 12% higher O.D. retention rate (%), confirming improved light resistance.

[0239] The O.D. retention rate (%) was measured using an image sample densitometer (product name "FD-7", manufactured by Konica Minolta), and represents the percentage change in the O.D. of black from the initial state to 10 hours later.

[0240] <Preparation and Evaluation of Water-Based Writing Instrument Ink> [Example 1-16] Ten parts of compound (1-4) represented by general formula (1), ten parts of compound (2-2) represented by general formula (2), and ten parts of compound (3-4) represented by general formula (3) were used as colorants. To these colorants, 0.6 parts of Prisurf A208N (Daiichi Kogyo Seiyaku Co., Ltd.), 1 part of methanol, and 0.5 parts of cellulose nanofiber Rheocrysta I-2AX (Daiichi Kogyo Seiyaku Co., Ltd.) were added. Then, 99 parts of ion-exchanged water were added to this mixture. The mixture was heated to an internal temperature of 80°C and stirred for 2 hours while removing the methanol. After cooling to room temperature, the mixture was dispersed in a homogenizer for 5 minutes to prepare water-based writing instrument ink (1-2).

[0241] [Comparative Example 1-9] A comparative aqueous ink (1-2) for writing instruments was prepared in the same manner as in Example 1-16, except that the colorants were 10 parts of compound (1-4) represented by general formula (1), 10 parts of comparative compound (1), and 10 parts of compound (3-4) represented by general formula (3).

[0242] [Evaluation of Storage Stability of Water-Based Writing Instrument Ink] 20 mL of each obtained water-based writing instrument ink was added to a 50 mL sample bottle, sealed, and left for one month under conditions of 60°C. After standing, the surface condition was observed under 20x magnification using a phase-contrast microscope (product name "BX53", manufactured by OLYMPUS Corporation). As a result of the observation, particle aggregation was observed in Comparative Examples 1-9, which did not use any of the compounds represented by general formulas (1), (2), and (3). On the other hand, no aggregation was observed in Example 1-16, which used all of the compounds represented by general formulas (1), (2), and (3). From this, it was confirmed that the storage stability was improved by using all of the compounds represented by general formulas (1), (2), and (3).

[0243] [Preparation of Water-Based Writing Instruments and Evaluation of Lightfastness] The obtained water-based writing instrument ink was filled into an ink reservoir made of polypropylene tubing with an inner diameter of 1.2 mm and a length of 140 mm. A ballpoint pen for evaluation testing was prepared, equipped with this ink reservoir and a phosphor bronze tip (ball diameter 0.7 mm). Using this ballpoint pen, a 2 cm square image sample was created on a recording medium with a constant writing pressure. Photographic paper (product name "Canon Photo Paper Glossy Pro [Platinum Grade] (model number: PT-201)", manufactured by Canon) was used as the recording medium.

[0244] The obtained image samples were placed in a xenon test apparatus (product name "Atlas Weatherometer Ci4000," manufactured by Toyo Seiki Seisakusho Co., Ltd.). After placement, the illuminance was set to 340 nm and 0.28 W / m². ２ The samples were exposed for 10 hours under the conditions of a black panel temperature of 40°C and relative humidity of 50%. Compared to Comparative Examples 1-9, which did not use any of the compounds represented by general formulas (1) to (3), Example 1-16, which used all of the compounds represented by general formulas (1) to (3), showed an 8.5% higher O.D. retention rate (%), confirming improved light resistance.

[0245] The O.D. remaining percentage (%) was determined in the same manner as in Examples 1-15.

[0246] <<Examples of the Second Embodiment>> <Preparation and Evaluation of Sublimation Transfer Ink> [Examples 2-1 to 2-12 and Comparative Examples 2-1 to 2-7] [Compounds represented by general formulas (1), (2), and (3), and comparative compounds] The compounds represented by general formulas (1), (2), and (3), and comparative compounds (1), (2), and (3) used in this embodiment are listed in Table 2-1. Comparative compounds (1), (2), and (3) are the same as those used in the examples of the first embodiment described above.

[0247] [Ink Preparation] A total of 3 parts of the compounds shown in Table 2-1, 16 parts of water, 1.2 parts of a dispersant (product name "DisperBYK190", manufactured by Bic Chemie), and 80 parts of 0.2 mmφ zirconia beads were placed in a zirconia grinding container. The mixing ratios of each compound shown in Table 2-1 are as described in Table 2-1. The mixture was then dispersed at 300 rpm for 4 hours using a planetary ball mill (product name "P-7 classic line", manufactured by Fritsch). The dispersion was diluted with a 15% glycerin aqueous solution to a solid content concentration of 7%, and then filtered through a 0.5 μm filter to obtain the ink.

[0248] [Examples 2-13 and 2-14] A total of 3 parts of the compounds shown in Table 2-1, 1 part of ADEKA stub LA-36 (manufactured by ADEKA Corporation), 15 parts of water, 1.2 parts of a dispersant (product name "DisperBYK190", manufactured by Bic Chemie), and 80 parts of 0.2 mmφ zirconia beads were placed in a zirconia grinding container. The mixture was dispersed at 300 rpm for 4 hours using a planetary ball mill (product name "P-7 classic line", manufactured by Fritsch). The dispersion was diluted with a 15% glycerin aqueous solution to a solid content concentration of 7%, and then filtered through a 0.5 μm filter to obtain ink.

[0249] [Printing process on transfer paper] Ink was filled into a modified Canon printer equipped with a piezo system, and a solid image with 100% duty cycle was printed onto sublimation transfer paper (product name "LUCY", manufactured by Daiki Co., Ltd.).

[0250] [Transfer process to fabric] After drying the obtained solid image, it was transferred to the polyester fabric, which was the recording medium, using a heat press machine at a heat press pressure of 60 SPI and the heat press temperature shown in Table 2-2, to create an image sample (image recording). Here, the heat press machine used was "AIR FUSION" manufactured by STAHLS, and the polyester fabric used was "Polyester Amunzen" manufactured by Tajimaya.

[0251] [Evaluation of Black Optical Density] The optical density (OD) of black in the image samples prepared at a hot press temperature of 200°C in the examples and comparative examples was measured using a reflectance densitometer (product name "FD-7", manufactured by Konica Minolta).

[0252] The measurement results were evaluated for density according to the following criteria. The evaluation results are recorded in the "Optical Density" column of Table 2-2. In the evaluation, a black O.D. of 1.50 or higher was considered to indicate high optical density. (Evaluation Criteria) A: Black O.D. is 1.70 or higher B: Black O.D. is 1.50 or higher but less than 1.70 C: Black O.D. is less than 1.50

[0253] [Heat Press Color Stability Evaluation] The color stability during heat pressing was calculated using the following formulas. The method for measuring the optical density (O.D.) of black in the image at each heat pressing temperature was the same as the method for evaluating the optical density of black described above, except that the heat pressing temperature was different. ・Color stability (%) during heat pressing at 180°C to 210°C = |O.D. of black at 210°C - O.D. of black at 180°C| (absolute value) ・Color stability (%) during heat pressing at 190°C to 200°C = |O.D. of black at 200°C - O.D. of black at 190°C| (absolute value)

[0254] The results obtained were evaluated according to the following evaluation criteria. The evaluation results are shown in the "Color Development Stability during Heat Pressing" column of Table 2-2. In the evaluation, if the O.D. difference (absolute value) of black was less than 0.50, it was judged that the color development stability was good. (Evaluation Criteria) A: O.D. difference (absolute value) of black is less than 0.30 B: O.D. difference (absolute value) of black is 0.30 or more and less than 0.50 C: O.D. difference (absolute value) of black is 0.50 or more

[0255] [Evaluation of lightfastness of printed materials (image recordings)] Each obtained black image sample was placed in a xenon test apparatus (product name "Atlas Weatherometer Ci4000", manufactured by Toyo Seiki Seisakusho Co., Ltd.) and tested at an illuminance of 340 nm and 0.28 W / m². ２ The samples were exposed for 20 hours under conditions of 40°C temperature and 50% relative humidity.

[0256] The colorimetric measurement of the reflectance density of black image samples before and after exposure was performed using a reflectance densitometer (product name "FD-7", manufactured by Konica Minolta).

[0257] The initial chromaticity before exposure was a ０ ＊ , b ０ ＊ , L ０ ＊ The chromaticity after exposure is set to a ＊ , b ＊ , L ＊ In this case, the color difference ΔE was defined and calculated as follows.

[0258]

[0259] The evaluation was then performed based on ΔE. The evaluation results are shown in the "Lightfastness of Polyester Fabrics" column of Table 2-2. The evaluation criteria are as follows: A ΔE of less than 7.00 after 20 hours was considered to indicate good lightfastness. (Evaluation Criteria) A: ΔE < 5.00 B: 5.00 ≤ ΔE < 7.00 C: 7.00 ≤ ΔE

[0260]

[0261]

[0262] As is clear from Tables 2-1 and 2-2 above, by using inks containing compounds represented by general formulas (1), (2), and (3), it was possible to obtain image recordings with high optical density, excellent color development stability, and lightfastness.

[0263] <<Examples of the Third Embodiment>> <Preparation and Evaluation of Thermal Transfer Recording Sheets> [Examples 3-1 to 3-11 and Comparative Examples 3-1 to 3-7] [Compounds represented by general formulas (1), (2), and (3), and comparative compounds] The compounds represented by general formulas (1), (2), and (3), and comparative compounds (1), (2), and (3) used in this embodiment are listed in Table 3-1. Comparative compounds (1), (2), and (3) are the same as those used in the examples of the first embodiment described above.

[0264] [Preparation of the colorant composition] A mixture of 45 parts methyl ethyl ketone and 45 parts toluene was gradually dissolved by adding 5 parts of polyvinyl butyral resin (trade name "KS-3", manufactured by Sekisui Chemical Co., Ltd.). A black colorant composition was obtained by adding and dissolving 5 parts of the compounds of the type shown in Table 3-1 below to this solution.

[0265] [Preparation of Thermal Transfer Recording Sheet] A polyethylene terephthalate film with a thickness of 4.5 μm (product name "Lumirror", manufactured by Toray Industries, Inc.) was used as the substrate. The above colorant composition was applied to this substrate and then dried to produce a thermal transfer recording sheet having a black colorant layer with a thickness of 1.0 μm after drying.

[0266] [Preparation of Image Samples] Using a thermal transfer recording sheet having the fabricated black colorant layer, a black image was transferred to a recording medium using a modified machine (product name "Selphy CP1300," manufactured by Canon) to create image samples (image recordings). As the recording medium, paper from the Selphy-specific color ink / paper set (product name "KL-36IP (L size)," manufactured by Canon) was used. Here, the image samples prepared using colorant compositions (3-1) to (3-11) are referred to as image samples (3-1) to (3-11), respectively. Similarly, the image samples prepared using comparative colorant compositions (3-1) to (3-7) are referred to as comparative image samples (3-1) to (3-7), respectively. In this modified machine, the amount of heat supplied for thermal transfer was reduced to approximately 80%.

[0267] The colorimetric measurements of the image samples were performed using a reflectance densitometer (product name "FD-7," manufactured by Konica Minolta).

[0268] [Evaluation of Storage Stability of Colorant Compositions (Inks)] The colorant compositions used in the examples and comparative examples were each placed in 100 mL sample bottles, sealed tightly, and stored at 10°C for one month. The presence or absence of aggregates and precipitates after storage was visually inspected and evaluated. The evaluation results are shown in Table 3-2. The evaluation criteria are as follows. In the evaluation, storage stability was judged to be good if "almost no aggregates and precipitates of the compound were observed" or "a small amount of aggregates and precipitates of the compound were observed". (Evaluation Criteria) A: Almost no aggregates and precipitates of the compound were observed B: A small amount of aggregates and precipitates of the compound were observed C: A considerable amount of aggregates and precipitates of the compound were observed

[0269] [Evaluation of lightfastness of printed materials (image recordings)] Each obtained black image sample was placed in a xenon test apparatus (product name "Atlas Weatherometer Ci4000", manufactured by Toyo Seiki Seisakusho Co., Ltd.). The illuminance was then set to 340 nm and 0.28 W / m². ２ The samples were exposed for 20 hours under conditions of 40°C and 50% relative humidity. The colorimetric reflection density of black image samples before and after exposure was measured using a reflectance densitometer (product name "FD-7", manufactured by Konica Minolta).

[0270] Let the initial chromaticity values before exposure be a ０ ＊ , b ０ ＊ , L ０ ＊ , respectively, and let the chromaticity values after exposure be a ＊ , b ＊ , L ＊ , respectively. The color difference ΔE was defined and calculated as follows.

[0271]

[0272] Evaluation was performed based on the obtained ΔE. The evaluation results are shown in Table 3-2. The evaluation criteria are as follows. Evaluation was determined that light resistance is good if ΔE after 20 hours is less than 7.00. (Evaluation Criteria) A: ΔE < 5.00 B: 5.00 ≦ ΔE < 7.00 C: 7.00 ≦ ΔE

[0273]

[0274]

[0275] As is clear from the above Tables 3-1 and 3-2, the storage stability of the color material composition used for forming the black color material layer of the thermal transfer recording sheet described in the Examples is good, and the image samples recorded using the thermal transfer recording sheets described in the Examples also had high light resistance. That is, in the thermal transfer recording sheets described in the Examples, mixed color fading could be suppressed by blending three types of color materials: the yellow color material, magenta color material, and cyan color material used in the black color material layer.

[0276] The present invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the present invention. Therefore, to define the scope of the present invention, the following claims are attached herewith.

[0277] The present application claims priority based on Japanese Patent Applications No. 2025-049641, No. 2025-049642, and No. 2025-049643 filed on March 25, 2025, and the entire contents of the descriptions thereof are incorporated herein by reference.

Claims

1. An ink comprising: a medium; and carrier particles dyed with a compound represented by the following general formula (1), a compound represented by the following general formula (2), and a compound represented by the following general formula (3): [In general formula (1), R １ represents a halogen atom, R ２ and R ３ each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an aryl group.]; [In general formula (2), R ４ represents -NH ２ group, a monoalkylamino group, a dialkylamino group or an acetylamino group, R ５ represents a halogen atom, R ６ represents a hydroxyl group or an alkoxy group.]; [In general formula (3), R ７ represents a hydrogen atom, an alkyl group or an acetylamino group, R ８ and R ９ each independently represent an alkyl group having 1 to 8 carbon atoms.].[] 2. In the above general formula (1), R １ is a chlorine atom, R ２ is a methyl group, R ３ The ink according to claim 1, wherein is an alkyl group having 1 to 8 carbon atoms.

3. In the general formula (2) above, R ４ ga-NH ２ It is a group or a monomethylamino group, R ５ is a bromine atom, R ６ The ink according to claim 1 or 2, wherein is a hydroxyl group or a methoxy group.

4. In the above general formula (3), R ７ R is a methyl group or an acetylamino group, ８ and R ９ The ink according to any one of claims 1 to 3, wherein each is independently an alkyl group having 1 to 4 carbon atoms.

5. The ink according to any one of claims 1 to 4, wherein the mass ratio of the compound represented by general formula (1), the compound represented by general formula (2), and the compound represented by general formula (3) is 2 parts by mass or more and 15 parts by mass or less of the compound represented by general formula (2) and 3 parts by mass or more and 30 parts by mass or less of the compound represented by general formula (3) per 10 parts by mass of the compound represented by general formula (1).

6. The ink according to any one of claims 1 to 5, which contains a dispersant.

7. The ink according to any one of claims 1 to 6, further comprising a resin present in a dissolved state in the medium.

8. The ink according to any one of claims 1 to 7, which is for oil-based writing instruments, water-based writing instruments, or inkjet applications.

9. An ink characterized by containing an aqueous medium, a dispersant, a compound represented by the following general formula (1), a compound represented by the following general formula (2), and a compound represented by the following general formula (3): [In general formula (1), R １ represents a halogen atom, R ２ and R ３ Each of these independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an aryl group. [In general formula (2), R ４ is, -NH ２ R represents a group, a monoalkylamino group, a dialkylamino group, or an acetylamino group. ５ R represents a halogen atom. ６ [This represents a hydroxyl group or an alkoxy group.] [In general formula (3), R ７ R represents a hydrogen atom, an alkyl group, or an acetylamino group. ８ and R ９ Each of these independently represents an alkyl group having 1 to 8 carbon atoms.

10. In the above general formula (1), R １ is a chlorine atom, R ２ is a methyl group, R ３ The ink according to claim 9, wherein is an alkyl group having 1 to 8 carbon atoms.

11. In the above general formula (2), R ４ ga-NH ２ It is a group or a monomethylamino group, R ５ is a bromine atom, R ６ The ink according to claim 9 or 10, wherein is a hydroxyl group or a methoxy group.

12. In the above general formula (3), R ７ R is a methyl group or an acetylamino group, ８ and R ９ The ink according to any one of claims 9 to 11, wherein each is independently an alkyl group having 1 to 4 carbon atoms.

13. The ink according to any one of claims 9 to 12, wherein the mass ratio of the compound represented by general formula (1), the compound represented by general formula (2), and the compound represented by general formula (3) is 2 parts by mass or more and 15 parts by mass or less of the compound represented by general formula (2) and 3 parts by mass or more and 30 parts by mass or less of the compound represented by general formula (3) per 10 parts by mass of the compound represented by general formula (1).

14. A thermal transfer recording sheet having a base material and a black colorant layer formed on the base material, characterized in that the black colorant layer contains a compound represented by the following general formula (1), a compound represented by the following general formula (2), and a compound represented by the following general formula (3): [In general formula (1), R １ represents a halogen atom, R ２ and R ３ Each of these independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an aryl group. [In general formula (2), R ４ is, -NH ２ R represents a group, a monoalkylamino group, a dialkylamino group, or an acetylamino group. ５ R represents a halogen atom. ６ [This represents a hydroxyl group or an alkoxy group.] [In general formula (3), R ７ R represents a hydrogen atom, an alkyl group, or an acetylamino group. ８ and R ９ Each of these independently represents an alkyl group having 1 to 8 carbon atoms.

15. In the above general formula (1), R １ is a chlorine atom, R ２ is a methyl group, R ３ The thermal transfer recording sheet according to claim 14, wherein is an alkyl group having 1 to 8 carbon atoms.

16. In the above general formula (2), R ４ ga-NH ２ It is a group or a monomethylamino group, R ５ is a bromine atom, R ６ The thermal transfer recording sheet according to claim 14 or 15, wherein the group is a hydroxyl group or a methoxy group.

17. In the above general formula (3), R ７ R is a methyl group or an acetylamino group, ８ and R ９ However, each is independently an alkyl group having 1 to 4 carbon atoms, as described in any one of claims 14 to 16.

18. A thermal transfer recording sheet according to any one of claims 14 to 17, wherein the mass ratio of the compound represented by general formula (1), the compound represented by general formula (2), and the compound represented by general formula (3) is 2 parts by mass or more and 15 parts by mass or less of the compound represented by general formula (2) and 3 parts by mass or more and 30 parts by mass or less of the compound represented by general formula (3) per 10 parts by mass of the compound represented by general formula (1).

19. A thermal transfer recording sheet according to any one of claims 14 to 18, further comprising a yellow colorant layer, a magenta colorant layer, and a cyan colorant layer, wherein the yellow colorant layer, the magenta colorant layer, the cyan colorant layer, and the black colorant layer are formed sequentially on the substrate.

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