JP2015120245A - Thermal transfer sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal transfer sheet with high efficiency in dye transfer, having sufficient storage stability, free from a problem of detachability in a print condition under an environment from a low temperature to high temperature, without abnormal transfer, and capable of preventing a bubble from generating from coating liquid at coating of a dye layer.SOLUTION: In a thermal transfer sheet 1, a dye layer 3 is formed on one surface of a substrate 2, and a heat-resistant lubricant layer 4 is formed on the other surface of the substrate 2. The dye layer 3 includes a sublimable dye, a nitrocellulose resin and a modified silicone having at least one of an alkyl group and an aralkyl group.

Description

  The present invention relates to a thermal transfer sheet.

  Conventionally, a thermal transfer sheet in which a dye layer, which is a color material layer carrying a sublimation dye with an appropriate binder, is provided on one surface of a substrate such as a polyester film, and a thermal transfer image-receiving sheet as a transfer target are superimposed, There is known a sublimation transfer method in which a sublimation dye is transferred to a transfer medium by performing heat treatment with a thermal head while bringing the other surface side of the substrate into contact with the thermal head. According to this sublimation transfer method, the transfer amount of sublimable dye can be controlled in dot units by the amount of energy applied to the thermal transfer sheet, so that density gradation is possible, the image is very clear, and transparency In addition, it is excellent in halftone color reproducibility and gradation, and can form a high-quality image comparable to a full-color photographic image.

  The dye layer of the above-described sublimation transfer type thermal transfer sheet has the sublimation dye contained in the dye layer well held in the binder resin during storage of the thermal transfer sheet, and the sublimation dye from the binder resin good during thermal transfer. In other words, high storage stability and dye transfer efficiency are required.

  As a binder resin having high storage stability, a butyral type resin or an acetal type resin is known (see Patent Document 1). The dye layer containing the above butyral or acetal resin as a binder resin is excellent in storage stability, but has a problem that the dye transfer efficiency is low and the printing density is low. Therefore, when these binder resins are used, (1) the amount of dye layer applied is increased to increase the absolute amount of sublimable dye contained in the dye layer, or (2) the dye of the thermal transfer sheet. It is necessary to improve the print density by a method such as increasing the mass ratio (D / B ratio) of the sublimable dye / binder resin in the layer.

  However, when the coating amount of the above (1) dye layer is increased, a large amount of sublimation dye that does not migrate to the thermal transfer image-receiving sheet side remains in the dye layer, that is, wasteful sublimation dye increases. In terms of cost, it is not preferable. Also, when (2) the D / B ratio is increased until a sufficient print density is achieved, the butyral or acetal binder resin cannot retain the sublimable dye, and the storage stability is significantly reduced. To do. When storage stability is reduced, when the thermal transfer sheet is stored in a wound state, the dye layer and the back layer provided on the opposite side of the substrate come into contact with each other, so that the dye layer is sublimated from the back layer. The dye migrates (kick), causing a decrease in sheet transportability and a decrease in the function of the back layer. Furthermore, when the product is rolled back onto a bobbin or the like to make it into a product, the dye transferred to the back layer is retransferred (backed) to the dye layer of another hue that is not the dye layer containing the dye, and the resulting image is contaminated. It will be in the state. In addition, when stored in a high-temperature and high-humidity environment, the dye deposits on the surface of the dye layer, and during printing, the deposited dye comes into contact with the unprinted portion, resulting in soiling that contaminates the unprinted portion. There are various problems.

  Cellulose resins such as cellulose acetate propionate and ethyl cellulose are known as binder resins whose main purpose is to improve dye transfer efficiency. However, these binder resins whose main purpose is to improve dye transfer efficiency are excellent in dye transfer efficiency, but have low storage stability, especially when the coating amount of the dye layer is reduced, and the D / B ratio. When the value is increased, the storage stability is lowered and the above-mentioned problem is caused.

  In other words, storage stability and dye transfer efficiency are in a trade-off relationship that if one is pursued, the other must be sacrificed, and if a material with high storage stability is selected, the dye transfer efficiency decreases. On the other hand, when a material having high dye transfer efficiency is selected, the storage stability tends to decrease. At present, there is no binder that satisfies both storage stability and dye transfer efficiency. In addition, when forming an image in a high gradation region or a medium gradation region in which high thermal energy is applied to the dye layer, a so-called abnormal transfer problem may occur in which the dye layer and the receiving layer of the thermal transfer image receiving sheet cause sticking. .

  In order to solve the above problem, the present applicant has proposed Patent Document 2 and was able to improve it. However, under special circumstances at low temperatures, there may be a problem with the peelability of the thermal transfer sheet and thermal transfer image-receiving sheet after printing, and in the case of high-speed coating when the dye layer is coated on the substrate, It was found that bubbles were generated from the dye layer coating liquid, leading to deterioration of the coating surface quality of the dye layer.

JP 2009-286060 A JP2013-212609A

  The present invention has been made in such a situation, has high dye transfer efficiency, has sufficient storage stability, and does not cause a problem in releasability even under printing conditions in an environment from low temperature to high temperature. Further, it is a main object to provide a thermal transfer sheet that does not cause abnormal transfer and can further prevent the generation of bubbles from the coating liquid during coating of the dye layer.

The above object is achieved by the present invention described below. That is, the present invention is a thermal transfer sheet provided with a dye layer on one side of a substrate and a heat-resistant slipping layer on the other side of the substrate,
The dye layer contains a sublimable dye, a nitrocellulose resin, and a modified silicone having at least one of an alkyl group or an aralkyl group.

一般式（１）中のＲ１、Ｒ２は、それぞれ独立に水素原子、置換あるいは非置換のアルキル基、ビニル基、アリル基、アリール基、アルコキシアルキル基、アラルキル基、アルコキシカルボニルアルキル基、カルボキシアルキル基、またはアルコキシカルボキシアルキル基を表し、Ｒ１とＲ２とは互いに環を形成してもよい。Ｒ３は水酸基、ハロゲン原子、シアノ基、置換あるいは非置換のアルキル基、アルキルホルミルアミノ基、アルキルスルホニルアミノ基、ホルミルアミノ基、アリルホルミルアミノ基、スルホニルアミノ基、アリルスルホニルアミノ基、カルバモイル基、スルファモイル基、アミノ基、カルボキシル基、アルコキシ基またはウレイド基を表し、Ｒ４、Ｒ５は、水素原子、ハロゲン原子、シアノ基、ニトロ基、置換あるいは非置換のアルキル基、アリル基、置換あるいは非置換のアリール基、アラルキル基、アルコキシアルキル基、アラルキルオキシアルキル基、チオアルキル基、アリルオキシアルキル基、アリールオキシアルキル基、カルボモイル基、スルファモイル基、オキシカルボニル基、アミノ基、ホルミルアミノ基、スルホニルアミノ基、アルコキシカルボニルアルキル基、複素環基、シクロアルキル基、アルキルチオ基、アルキルスルフィニル基、またはアルキルスルホニル基を表す。 The sublimable dye of the dye layer contains one or more dyes selected from the group consisting of general formula (1), general formula (2), general formula (3), and general formula (4). The composition of the thermal transfer sheet is as follows.

R1 and R2 in the general formula (1) are each independently a hydrogen atom, substituted or unsubstituted alkyl group, vinyl group, allyl group, aryl group, alkoxyalkyl group, aralkyl group, alkoxycarbonylalkyl group, carboxyalkyl group. Or an alkoxycarboxyalkyl group, and R 1 and R 2 may form a ring with each other. R3 is hydroxyl group, halogen atom, cyano group, substituted or unsubstituted alkyl group, alkylformylamino group, alkylsulfonylamino group, formylamino group, allylformylamino group, sulfonylamino group, allylsulfonylamino group, carbamoyl group, sulfamoyl Group, amino group, carboxyl group, alkoxy group or ureido group, R4 and R5 are hydrogen atom, halogen atom, cyano group, nitro group, substituted or unsubstituted alkyl group, allyl group, substituted or unsubstituted aryl Group, aralkyl group, alkoxyalkyl group, aralkyloxyalkyl group, thioalkyl group, allyloxyalkyl group, aryloxyalkyl group, carbomoyl group, sulfamoyl group, oxycarbonyl group, amino group, formylamino group, sulfonylamido It represents group, alkoxycarbonylalkyl group, a heterocyclic group, a cycloalkyl group, an alkylthio group, an alkylsulfinyl group or an alkylsulfonyl group.

一般式（２）中のＲ１、Ｒ２はアルケニル基、アラルキル基、または置換あるいは非置換のアルキル基を表し、Ｒ３は水素原子、メチル基、メトキシ基、またはハロゲン原子をＲ４は水素原子、メチル基、メトキシ基、ホルミルアミノ基、アルキルカルボニルアミノ基、アルキルスルホニルアミノ基、またはアルコキシカルボニルアミノ基を表し、Ｒ５は、アルキル基、アルケニル基、アリル基、アリール基、シアノアルキル基、置換あるいは非置換のアルコキシカルボニルアルキル基を表す。

In general formula (2), R1 and R2 represent an alkenyl group, an aralkyl group, or a substituted or unsubstituted alkyl group, R3 represents a hydrogen atom, a methyl group, a methoxy group, or a halogen atom, and R4 represents a hydrogen atom or a methyl group. Represents a methoxy group, a formylamino group, an alkylcarbonylamino group, an alkylsulfonylamino group, or an alkoxycarbonylamino group, and R5 represents an alkyl group, an alkenyl group, an allyl group, an aryl group, a cyanoalkyl group, a substituted or unsubstituted group. Represents an alkoxycarbonylalkyl group.

一般式（３）中のＸ及びＹは−Ｓ−、−Ｏ−又は−ＳＯ₂−を表し、Ｒ１及びＲ２は置換又は非置換のアルキル基、シクロアルキル基、アリール基又はアリル基を表す。

X and Y in the general formula (3) in -S -, - O-or -SO ₂ - represents, R1 and R2 represent a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group or an allyl group.

一般式（４）中のＸは−Ｓ−、−Ｏ−又は−ＳＯ₂−を表し、Ｒ１は置換又は非置換のアルキル基、シクロアルキル基、アリール基又はアリル基を表す。

The X in the general formula (4) -S -, - O-or -SO ₂ - represents, R1 represents a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group or an allyl group.

Further, in the sublimation dye, in the general formula (1), R1, R2, R3, and R4 are each a substituted or unsubstituted alkyl group, R5 is a substituted or unsubstituted aryl group, and the general formula In (2), R1 and R2 are alkyl groups, R3 and R4 are hydrogen atoms or alkylcarbonylamino groups, R5 is an alkenyl group, and in the general formula (3), X and Y are —O—. Wherein R 1 and R 2 are substituted or unsubstituted aryl groups, and in the general formula (4), X and Y are —O—, and R 1 is a substituted or unsubstituted aryl group, The configuration of the thermal transfer sheet is as follows.

  According to the thermal transfer sheet of the present invention, the dye transfer efficiency is high, the storage stability is sufficient, and there is no problem in releasability even under printing conditions in an environment from low temperature to high temperature, and abnormal transfer is also possible. Without generating, it is possible to further prevent the generation of bubbles from the coating liquid during the dye layer coating.

It is a schematic sectional drawing which shows one embodiment of the thermal transfer sheet of this invention. It is a schematic sectional drawing which shows other embodiment of the thermal transfer sheet of this invention.

Next, an embodiment of the invention will be described in detail.
FIG. 1 shows one embodiment of the thermal transfer sheet of the present invention. The illustrated thermal transfer sheet 1 is a thermal transfer sheet 1 having a dye layer 3 on one surface of a substrate 2 via a dye primer layer 5 and a heat-resistant slipping layer 4 on the other surface of the substrate 2. is there.

  FIG. 2 shows another embodiment of the thermal transfer sheet of the present invention. The illustrated thermal transfer sheet 1 has a dye layer of three colors, a yellow dye layer (3Y), a magenta dye layer (3M), and a cyan dye layer (3C), on one surface of a substrate 2 via a dye primer layer 5. 3 is a thermal transfer sheet 1 having a heat-resistant slipping layer 4 on the other surface of the substrate 2 in a configuration in which 3 is repeatedly provided in this order.

Hereinafter, each configuration of the thermal transfer sheet of the present invention will be described.
(Base material)
The substrate 2 used in the thermal transfer sheet of the present invention is not particularly limited as long as it has transparency in addition to a certain degree of heat resistance and strength, and a conventionally known material is appropriately selected and used. Can do. Examples of such a substrate 1 include polyethylene terephthalate film, 1,4-polycyclohexylenedimethylene terephthalate film, polyethylene naphthalate film, polyphenylene sulfide having a thickness of about 0.5 to 50 μm, preferably about 1 to 10 μm. Film, polystyrene film, polypropylene film, polysulfone film, aramid film, polycarbonate film, polyvinyl alcohol film, cellophane, cellulose derivatives such as cellulose acetate, polyethylene film, polyvinyl chloride film, nylon film, polyimide film, ionomer film, etc. . Furthermore, each of these materials can be used alone, but may be used as a laminate in combination with other materials.

(Dye layer)
The dye layer 3 contains a sublimable dye, a nitrocellulose resin, and a modified silicone having at least one of an alkyl group or an aralkyl group. The sublimable dye contained in the dye layer preferably has a sufficient color density and does not discolor due to light, heat, temperature or the like. Examples of such sublimable dyes include diarylmethane dyes, triarylmethane dyes, thiazole dyes, merocyanine dyes, pyrazolone dyes, methine dyes, indoaniline dyes, acetophenone azomethine, pyrazoloazomethine, imidazole Azomethine dyes such as azomethine, imidazoazomethine and pyridone azomethine, xanthene dyes, oxazine dyes, cyanostyrene dyes such as dicyanostyrene and tricyanostyrene, thiazine dyes, azine dyes, acridine dyes, benzeneazo dyes, Pyridoneazo, thiophenazo, isothiazole azo, pyrrole azo, pyrazole azo, imidazole azo, thiadiazole azo, triazole azo, disazo azo dyes, spiropyran dyes, indolinospiro Run dyes, fluoran dyes, rhodamine lactam dyes, naphthoquinone dyes, anthraquinone dyes, quinophthalone dyes.

  Specifically, red dyes such as Disperse Red 60, Disperse Violet 26, Ceres Red 7B, Samaraon Red F3BS, yellow dyes such as Disperse Yellow 231, PTY-52, Macrolex Yellow 6G, Solvent Blue 63, Waxolin Blue AP-FW, Holon Brilliant Blue S-R, MS Blue 100, C.I. I. And blue dyes such as Solvent Blue 22.

  In the present invention, a nitrocellulose resin is used as the binder resin in the dye layer. The reason is that nitrocellulose resin has good storage stability of sublimation dyes, and when the thermal transfer sheet is stored in a wound state, the sublimation dye contained in the dye layer is transferred to the heat-resistant slip layer. Can be suppressed. Further, since the nitrocellulose resin has a high dye transfer efficiency, the dye transfer efficiency of the sublimation dye is also good, and a high-density image can be formed.

  While this nitrocellulose resin has the advantage of excellent storage stability and dye transfer efficiency, it has a low releasability compared to polyvinyl butyral resin and polyvinyl acetal resin. However, in the present invention, by using a nitrocellulose resin and a modified silicone having at least one of an alkyl group or an aralkyl group which is a release agent, it is possible to improve the releasability during image formation.

  The viscosity of the nitrocellulose resin is not particularly limited, but when the dye layer contains a nitrocellulose resin having a viscosity of less than 1/16 according to JIS K-6703, the storage stability tends to decrease. On the other hand, when a nitrocellulose resin having a viscosity of more than 120 according to JIS K-6703 is contained in the dye layer, there is a possibility that ink mist or the like may be generated when the dye layer is formed.

  Considering this point, the dye layer preferably contains 1/16 or more and 120 or less nitrocellulose resin according to JIS K-6703. In other words, the viscosity according to JIS K-6703 (solution concentration 25%) is 1.0 second to 14.9 seconds, the viscosity according to JIS K-6703 (solution concentration 20%) is 6.0 seconds to 8.0 seconds, Or the viscosity (solution concentration 12.2%) according to JIS K-6703 is preferably 4.0 seconds to 140.0 seconds. By containing a nitrocellulose resin having a viscosity in this range in accordance with JIS K-6703 in the dye layer, the storage stability can be further improved, and ink mist and the like are prevented from being generated when the dye layer is formed. be able to.

  As the nitrocellulose resin having a viscosity within the above range, a commercially available product can be used as it is. Examples of the viscosity within the above range include, for example, the types and viscosity symbols specified in JIS K-6703 manufactured by Taihei Chemicals Co., Ltd., H1 / 16, H1 / 8, L1 / 8, H1 / 4. Examples include L1 / 4, H1 / 2, H1 ", H5", H20, H60, and H120. In addition, DHX3-5, DHX5-10, DHX8-13, DHX11-16, DHX30-50, DHX40-70, DHL25-45, DHL120-170, H20 (160-210) manufactured by Inabata Sangyo Co., Ltd. , DHM10-25, SL-1, DLX3-5, DLX5-8, DLX8-13, DLX30-50, etc. can also be used.

  The nitrocellulose resin preferably has a nitrogen content (nitrification degree) of 10%. In consideration of handling safety, the nitrogen content is preferably 12.3% or less. By containing a nitrocellulose resin having a nitrogen content of 10% or more, further improvement in dye transfer efficiency in the dye layer is expected.

  The dye layer may contain only a nitrocellulose resin as a binder resin, and other binder resins can be used in combination with the nitrocellulose resin. Examples of other binder resins include cellulose resins such as ethyl cellulose resin, hydroxyethyl cellulose resin, ethyl hydroxy cellulose resin, methyl cellulose resin, and cellulose acetate resin, polyvinyl alcohol resin, polyvinyl acetate resin, polyvinyl butyral resin, polyvinyl acetal resin, Examples thereof include vinyl resins such as polyvinyl pyrrolidone, acrylic resins such as poly (meth) acrylate and poly (meth) acrylamide, polyurethane resins, polyamide resins, and polyester resins. These resins are preferably contained within a range of 15% by mass or less based on the total solid content of the dye layer. When the content of these resins exceeds 15% by mass, dye transfer efficiency and dye storage stability tend to be lowered.

  The mass ratio (D / B ratio (sublimation dye / binder resin)) between the sublimable dye and the nitrocellulose resin contained in the dye layer is preferably 2.0 or more. By setting the D / B ratio to 2.0 or more, an image having a sufficient print density can be obtained. In general, when the D / B ratio is 2.0 or more, a conventionally known binder resin that has been used so far cannot retain a sublimable dye. However, in the present invention, the dye layer contains nitrocellulose. Since the resin is contained, the sublimable dye can be sufficiently retained even when the D / B ratio is 2.0 or more, and the storage stability is excellent. The upper limit value of the D / B ratio is not particularly limited, but when the D / B ratio exceeds 3.5, the dye amount of the sublimation dye with respect to the binder resin is too large, and the binder resin is not sublimable. In some cases, the storage stability cannot be maintained and the storage stability is lowered. Therefore, considering this point, the D / B ratio is preferably in the range of 2.0 to 3.5.

The modified silicone having an alkyl group as the modified silicone contained in the dye layer is, in other words, an alkyl-modified silicone oil. As shown in the following chemical formulas 5 and 6, [OSi (CH ₃ ) (R ₁ )] And / or [OSi (R ₁ ) (R ₂ )]. Here, R ₁ and R ₂ are each independently selected from alkyl groups having 1 or more carbon atoms. The alkyl group may be linear or side chain. Examples of R ₁ and R ₂ include methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, cyclopentyl Group, cyclohexyl group, cycloheptyl group, 2-methylcyclohexyl group and the like.

ｍ及びｎは、正の整数である。

m and n are positive integers.

ｍ及びｎは、正の整数である。

m and n are positive integers.

  Alkyl-modified silicones can also be obtained as commercial products. Specific examples include trade name “KF412” (manufactured by Shin-Etsu Chemical Co., Ltd.), trade name “KF413” (manufactured by Shin-Etsu Chemical Co., Ltd.), trade name. “KF414” (manufactured by Shin-Etsu Chemical Co., Ltd.), trade name “SF8416” (manufactured by Toray Dow Corning Silicone Co., Ltd.), and the like.

As the modified silicone contained in the dye layer, the modified silicone having an aralkyl group is, in other words, an aralkyl-modified silicone. As shown in the above chemical formulas 5 and 6, [OSi (CH ₃ ) (R ₁ ) And / or [OSi (R ₁ ) (R ₂ )], wherein R _{1 and} R ₂ are each independently an alkylphenyl group, a dialkylphenyl group, an alkylnaphthyl group, a dialkylnaphthyl group, or the like. To be elected. Among them, an alkylphenyl group is preferably used, and an isopropylphenyl group is particularly preferably used. In addition, it is preferable that R ₁ or R ₂ has the aralkyl group, and the group facing the R ₁ or R ₂ having the aralkyl group has the alkyl group described above.

  Aralkyl-modified silicone can also be obtained as a commercial product. Specific examples include trade name “KF410” (manufactured by Shin-Etsu Chemical Co., Ltd.), trade name “SH203” (manufactured by Toray Dow Corning Silicone Co., Ltd.), product The name “SH230” (manufactured by Toray Dow Corning Silicone Co., Ltd.) can be used.

The addition of a modified silicone having at least one of the above-mentioned alkyl group or aralkyl group to the dye layer can increase the releasability (peelability) between the thermal transfer image-receiving sheet and the thermal transfer sheet during image formation. Furthermore, the main reason is that bubbles can be prevented from being generated from the dye layer coating liquid at the time of high-speed coating of the dye layer on the substrate.
The modified silicone having at least one of the above alkyl group and aralkyl group is preferably contained in the range of 0.5% by mass or more and 10% by mass or less with respect to the total mass of the dye layer. More preferably, the content is 2% by mass or more and 5% by mass or less. If the content of the modified silicone is too small, the functions of the above-mentioned releasability and prevention of foaming cannot be fully exhibited. On the other hand, if the content of the modified silicone is too large, the substrate and the dye There exists a tendency for adhesiveness with a layer to fall.

  The dye layer may contain additives such as inorganic fine particles and organic fine particles in addition to the sublimable dye, the nitrocellulose resin and the modified silicone. Examples of the inorganic fine particles include carbon black, aluminum, molybdenum disulfide, and silica fine particles. Examples of the organic fine particles include polyethylene wax.

The coating amount of the dye layer is preferably 0.45 g / m ² or less when dried. By making the coating amount of the dye layer within this range, it is possible to improve the dye transfer efficiency at the time of image formation, and it is possible to transfer the sublimation dye contained in the dye layer onto the thermal transfer image receiving sheet without waste. . When the coating amount of the dye layer exceeds 0.45 g / m ² at the time of drying, the dye transfer efficiency tends to decrease. There is no particular limitation on the lower limit of the dye layer, but when the coating amount of the dye layer is less than 0.13 g / m ² at the time of drying, the blending ratio of the sublimable dye to the nitrocellulose resin may be increased. In some cases, sufficient print density cannot be obtained. Therefore, considering this point, the coating amount of the dye layer is preferably 0.13 g / m ² or more 0.45 g / m ² or less at the time of drying.

  The method for forming the dye layer is not particularly limited, and is a sublimable dye, a nitrocellulose resin, a modified silicone having at least one of an alkyl group or an aralkyl group, and, if necessary, an additive such as a release agent or inorganic fine particles. Gravure printing, die coating printing, bar coating printing, screen printing of coating solution dissolved in organic solvent or water such as toluene, methyl ethyl ketone, isopropyl alcohol, ethanol, cyclohexanone, DMF, etc. Alternatively, it can be formed by applying and drying by means such as reverse roll coating printing using a gravure plate.

  In the embodiment shown in FIG. 1, a single dye layer 3 is provided on the substrate 2, but a dye layer containing different sublimation dyes, such as a yellow dye, as shown in FIG. The three color dye layers 3 of the layer (3Y), the magenta dye layer (3M), and the cyan dye layer (3C) may be repeatedly provided on the same surface of the same base material in the order of surfaces. In addition, a transferable protective layer may be provided on the same surface.

(Dye primer layer)
In the present invention, it is preferable to provide the dye primer layer 5 between the substrate and the dye layer. By providing the dye primer layer, the adhesion between the substrate and the dye layer can be improved, and abnormal transfer of the dye layer to the thermal transfer image receiving sheet can be prevented during thermal transfer.

  The resins constituting the dye primer layer include polyester resins, polyvinyl pyrrolidone resins, polyvinyl alcohol resins, hydroxyethyl cellulose, polyacrylate resins, polyvinyl acetate resins, polyurethane resins, styrene acrylate resins, polyacrylamide resins. Examples thereof include resins, polyamide resins, polyether resins, polystyrene resins, polyethylene resins, polypropylene resins, polyvinyl chloride resins, polyvinyl acetal resins such as polyvinyl acetoacetal and polyvinyl butyral, and the like.

  The dye primer layer may contain inorganic fine particles, for example, colloidal inorganic pigment ultrafine particles. This prevents dye migration from the dye layer to the dye primer layer during image formation, and enables effective dye diffusion to the receiving layer side of the thermal transfer image-receiving sheet, thereby increasing the print density.

  Conventionally known compounds can be used as the inorganic fine particles. For example, silica (colloidal silica), alumina or alumina hydrate (alumina sol, colloidal alumina, cationic aluminum oxide or its hydrate, suspect boehmite, etc.), aluminum silicate, magnesium silicate, magnesium carbonate, magnesium oxide, oxidation Examples include titanium. In particular, colloidal silica and alumina sol are preferably used. These colloidal inorganic pigment ultrafine particles are preferably used with an average primary particle size of 100 nm or less, preferably 50 nm or less.

For the dye primer layer, the resin exemplified above and the coating solution for the dye primer layer in which the colloidal inorganic pigment ultrafine particles are dissolved or dispersed in an appropriate solvent are used as a gravure coating method, a roll coating method, a screen printing method, and a gravure plate. It can be formed by coating and drying by a conventionally known forming means such as the reverse roll coating method used. The coating amount of the dye coating solution for a primer layer is preferably 0.02g / m ² ~1.0g / m ² approximately at the time of drying.

(Heat resistant slipping layer)
On the other surface of the substrate, a heat-resistant slipping layer 4 is provided for improving heat resistance and running performance of the thermal head during printing. The heat-resistant slip layer 4 is an essential component in the thermal transfer sheet of the present invention.

  The heat-resistant slip layer 4 can be formed by appropriately selecting a conventionally known thermoplastic resin or the like. As such a thermoplastic resin, for example, polyester resins, polyacrylate resins, polyvinyl acetate resins, styrene acrylate resins, polyurethane resins, polyethylene resins, polypropylene resins, and other polyolefin resins, Polystyrene resin, polyvinyl chloride resin, polyether resin, polyamide resin, polyimide resin, polyamideimide resin, polycarbonate resin, polyacrylamide resin, polyvinyl chloride resin, polyvinyl butyral resin, polyvinyl acetoacetal resin, etc. Examples thereof include thermoplastic resins such as polyvinyl acetal resin, and silicone modified products thereof.

  Moreover, you may add a hardening | curing agent to above-described resin. As the polyisocyanate resin that functions as a curing agent, conventionally known ones can be used without any particular limitation. Among them, it is desirable to use an adduct of an aromatic isocyanate. As the aromatic polyisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, or a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, 1,5-naphthalene diisocyanate, tolidine diisocyanate, Examples include p-phenylene diisocyanate, trans-cyclohexane-1,4-diisocyanate, xylylene diisocyanate, triphenylmethane triisocyanate, and tris (isocyanatophenyl) thiophosphate, particularly 2,4-toluene diisocyanate and 2,6-toluene diisocyanate. Or, a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate is preferable. Such a polyisocyanate resin crosslinks the hydroxyl group-containing thermoplastic resin using the hydroxyl group to improve the coating strength and heat resistance of the heat resistant slipping layer.

  In addition to the above thermoplastic resin, the heat-resistant slipping layer has a release agent such as wax, higher fatty acid amide, phosphate ester compound, metal soap, silicone oil, surfactant, etc., for the purpose of improving slip properties, Various additives such as organic powders such as fluororesin, inorganic particles such as silica, clay, talc and calcium carbonate are preferably contained, and at least one kind of phosphate ester or metal soap is contained. Particularly preferred.

The heat-resistant slipping layer is, for example, a coating liquid obtained by dispersing or dissolving the above-mentioned thermoplastic resin and various additives added as necessary in a suitable solvent on the surface opposite to the dye layer of the substrate. It can be formed by applying and drying by a known means such as a gravure printing method, a screen printing method, a reverse roll coating printing method using a gravure plate. The coating amount of the heat-resistant slipping layer, from the viewpoint of improvement of such as heat resistance, it is preferable that the coating amount after drying is 3 g / m ² or less, is possible to 0.1-2 g / m ² and more preferable.

  The thermal transfer sheet of the present invention heats and presses a predetermined portion with a thermal head or the like on the heat-resistant slipping layer on the side opposite to the dye layer of the base material, and the dye corresponding to the printing portion in the dye layer is transferred. It can be transferred to the material and printed. A thermal transfer image receiving sheet or the like can be used as the transfer material. The thermal transfer image-receiving sheet is not particularly limited as long as the recording surface has dye acceptability. For example, a dye-receiving layer is formed on at least one surface of a substrate such as paper, metal, glass, or synthetic resin. Things can be mentioned. The printer used for performing the thermal transfer is not particularly limited, and a known thermal transfer printer can be used.

Next, the present invention will be described more specifically with reference to examples and comparative examples. “Part” in the text is based on mass unless otherwise specified.
Example 1
A polyethylene terephthalate film having a thickness of 5 μm is used as a substrate, and a coating solution for heat-resistant slipping layer having the following composition is applied to one surface of the substrate by a gravure coating method to 1.0 g / m ² when dried. Coating was performed to form a heat-resistant slipping layer. Next, the following dye primer layer coating solution was applied to the surface of the substrate opposite to the side on which the heat-resistant slip layer was provided, so that the dried primer primer layer was 0.10 g / m ^2. Formed. Next, the dye layer coating solution 1 having the following composition is coated on the dye primer layer with a gravure coater so as to be 0.35 g / m ² when dried, and dried at 80 ° C. for 2 minutes to form the dye layer. The thermal transfer sheet of Example 1 was obtained.

<Coating fluid for heat resistant slipping layer>
・ Polyvinyl acetal resin 90.3 parts (ESREC KS-1 manufactured by Sekisui Chemical Co., Ltd.)
・ 6.2 parts of polyisocyanate (Bernock D750, manufactured by Dainippon Ink & Chemicals, Inc.)
・ 0.62 parts of silicone resin filler (Tospearl 240 Momentive Performance Materials Japan GK)
-10 parts of zinc stearyl phosphate (LBT1830 purification, manufactured by Sakai Chemical Industry Co., Ltd.)
・ 10 parts of zinc stearate (SZ-PF manufactured by Sakai Chemical Industry Co., Ltd.)
・ 3 parts of polyethylene wax (Polywax 3000, manufactured by Toyo Adre Co., Ltd.)
・ Ethoxylated alcohol-modified wax 7 parts (Unitox 750, manufactured by Toyo Adre Co., Ltd.)
・ Methyl ethyl ketone 200 parts ・ Toluene 100 parts

<Dye primer layer coating solution>
・ 3 parts of polyvinylpyrrolidone resin (K-90 ISP)
・ Alumina sol (average primary particle size 10 × 100 nm, solid content 10%) 30 parts (alumina sol 200 Nissan Chemical Industries, Ltd.)
・ Water 50 parts ・ IPA (isopropyl alcohol) 17 parts

<Dye layer coating solution 1 (D / B ratio = 2.5)>
-1 part of a dye represented by the following general formula (1-1)-1.5 parts of a dye represented by the following general formula (4-1)-1.43 parts of a nitrocellulose resin (solid content 70% H40 equivalent) Min 1.0)
(DHM10-25 Inabata Sangyo Co., Ltd.)
・ Aralkyl modified silicone 0.02 parts (KF410 Shin-Etsu Chemical Co., Ltd.)
・ Solvent (Toluene / MEK = 1: 1) 96.5 parts

The above aralkyl-modified silicone (KF-410, manufactured by Shin-Etsu Silicone Co., Ltd.) has the structure of isopropylphenyl group represented by the chemical formula 5 shown above and R ₁ represented by the following chemical formula 9.
The aralkyl-modified silicone is contained at a ratio of 0.57% by mass (2% by mass with respect to the solid content of the nitrocellulose resin as the binder resin) with respect to the total solid content of the dye layer.

(Example 2)
A thermal transfer sheet was produced in the same manner as in Example 1 except that the dye layer coating solution 1 in the thermal transfer sheet produced in Example 1 was replaced with the dye layer coating solution 2 having the following composition.
<Dye layer coating solution 2>
1 part of the dye represented by the above general formula (1-1) 1.5 part of the dye represented by the above general formula (4-1) 1.43 parts of a nitrocellulose resin (solid content 70% equivalent to H40) Min 1.0)
(DHM10-25 Inabata Sangyo Co., Ltd.)
・ Alkyl aralkyl-modified silicone 0.02 parts (SH230 Toray Dow Corning Co., Ltd.)
・ Solvent (Toluene / MEK = 1: 1) 96.5 parts

The alkyl aralkyl-modified silicone (SH230 manufactured by Toray Dow Corning Silicone Co., Ltd.) is represented by the chemical formula 6 shown above, and in R ₁ and R ₂ , one is an alkyl group and the other is an aralkyl group. .
The alkyl / aralkyl-modified silicone is contained at a ratio of 0.57% by mass (2% by mass with respect to the solid content of the nitrocellulose resin as the binder resin) with respect to the total solid content of the dye layer.

(Example 3)
<Dye layer coating solution 3>
-0.25 part of the dye represented by the above general formula (1-1)-0.25 part of the dye represented by the following general formula (2-1)-Dye represented by the following general formula (3-1) 0.8 Part Dye represented by the above general formula (4-1) 1.2 part Nitrocellulose resin (solid content 70% H40 equivalent) 1.43 part (solid content 1.0 part)
(DHM10-25 Inabata Sangyo Co., Ltd.)
・ Alkyl aralkyl-modified silicone 0.04 parts (SH230 Toray Dow Corning Co., Ltd.)
・ Solvent (Toluene / MEK = 1: 1) 96.5 parts

上記アラルキル変性シリコーンは、染料層の固形分全体に対し１．１３質量％（バインダー樹脂であるニトロセルロース樹脂の固形分に対して４質量％）の割合で含有する。

The aralkyl-modified silicone is contained at a ratio of 1.13% by mass (4% by mass with respect to the solid content of the nitrocellulose resin as the binder resin) with respect to the total solid content of the dye layer.

(Comparative Example 1)
A thermal transfer sheet was produced in the same manner as in Example 1 except that the dye layer coating solution 1 in the thermal transfer sheet produced in Example 1 was replaced with the dye layer coating solution 4 having the following composition.
<Dye layer coating solution 4>
1 part of the dye represented by the above general formula (1-1) 1.5 part of the dye represented by the above general formula (4-1) 1.43 parts of a nitrocellulose resin (solid content 70% equivalent to H40) Min 1.0)
(DHM10-25 Inabata Sangyo Co., Ltd.)
・ Amino-modified silicone 0.02 parts (KF-8010 manufactured by Shin-Etsu Silicone Co., Ltd.)
・ Solvent (Toluene / MEK = 1: 1) 96.5 parts

The amino-modified silicone (KF-8010 manufactured by Shin-Etsu Silicone Co., Ltd.) has a structure in which amino groups are introduced at both ends of the polysiloxane.
The amino-modified silicone is contained at a ratio of 0.57% by mass (2% by mass with respect to the solid content of the nitrocellulose resin as the binder resin) with respect to the total solid content of the dye layer.

(Comparative Example 2)
A thermal transfer sheet was produced in the same manner as in Example 1 except that the dye layer coating solution 1 in the thermal transfer sheet produced in Example 1 was replaced with the dye layer coating solution 5 having the following composition.
<Dye layer coating solution 5>
1 part of the dye represented by the above general formula (1-1) 1.5 part of the dye represented by the above general formula (4-1) 1.43 parts of a nitrocellulose resin (solid content 70% equivalent to H40) Min 1.0)
(DHM10-25 Inabata Sangyo Co., Ltd.)
・ Amino-modified silicone 0.04 parts (KF-8010 manufactured by Shin-Etsu Silicone Co., Ltd.)
・ Solvent (Toluene / MEK = 1: 1) 96.5 parts

The amino-modified silicone (KF-8010 manufactured by Shin-Etsu Silicone Co., Ltd.) has a structure in which amino groups are introduced at both ends of the polysiloxane.
The amino-modified silicone is contained at a rate of 1.13% by mass (4% by mass with respect to the solid content of the nitrocellulose resin as the binder resin) with respect to the total solid content of the dye layer.

(Comparative Example 3)
A thermal transfer sheet was produced in the same manner as in Example 1 except that the dye layer coating solution 1 in the thermal transfer sheet produced in Example 1 was replaced with the dye layer coating solution 6 having the following composition.
<Dye layer coating liquid 6 (D / B ratio = 2.5)>
1 part of the dye represented by the above general formula (1-1) 1.5 part of the dye represented by the above general formula (4-1) 1.43 parts of a nitrocellulose resin (solid content 70% equivalent to H40) Min 1.0)
(DHM10-25 Inabata Sangyo Co., Ltd.)
・ Polyether-modified silicone 0.02 parts (FZ-2110 Toray Dow Corning Silicone Co., Ltd.))
・ Solvent (Toluene / MEK = 1: 1) 96.5 parts

The polyether-modified silicone is contained at a ratio of 0.57% by mass (2% by mass with respect to the solid content of the nitrocellulose resin as the binder resin) with respect to the total solid content of the dye layer.

(Comparative Example 4)
A thermal transfer sheet was produced in the same manner as in Example 1 except that the dye layer coating solution 1 in the thermal transfer sheet produced in Example 1 was replaced with the dye layer coating solution 7 having the following composition.
<Dye layer coating solution 7 (D / B ratio = 2.5)>
1 part of the dye represented by the above general formula (1-1) 1.5 part of the dye represented by the above general formula (4-1) 1.43 parts of a nitrocellulose resin (solid content 70% equivalent to H40) Min 1.0)
(DHM10-25 Inabata Sangyo Co., Ltd.)
・ Polyether-modified silicone 0.02 parts (FZ-2101 Toray Dow Corning Silicone Co., Ltd.))
・ Solvent (Toluene / MEK = 1: 1) 96.5 parts

The polyether-modified silicone is contained at a ratio of 0.57% by mass (2% by mass with respect to the solid content of the nitrocellulose resin as the binder resin) with respect to the total solid content of the dye layer.

(Comparative Example 5)
A thermal transfer sheet was produced in the same manner as in Example 1 except that the dye layer coating solution 1 in the thermal transfer sheet produced in Example 1 was replaced with the dye layer coating solution 8 having the following composition.
<Dye layer coating solution 8 (D / B ratio = 2.5)>
-1 part of the dye represented by the above general formula (1-1)-1.5 parts of the dye represented by the above general formula (4-1)-1.45 parts of a nitrocellulose resin (solid content 70% H40 equivalent) Min 1.0)
(DHM10-25 Inabata Sangyo Co., Ltd.)
・ Solvent (Toluene / MEK = 1: 1) 96.5 parts

(Evaluation of releasability of printed materials)
(Creation of thermal transfer image receiving sheet)
On the porous film layer made of porous polyethylene film (Toyopearl-SS P4255, manufactured by Toyobo Co., Ltd., 35 μm thick), an intermediate layer coating solution and a receiving layer coating solution having the following composition are obtained by a gravure reverse coating method. The intermediate layer and the receiving layer were formed by sequentially coating and drying. The adhesive layer is formed by applying and drying to the porous polyethylene film on the opposite side of the surface on which the intermediate layer and the receiving layer are provided, using a gravure reverse roll coat method using an adhesive layer coating solution having the following composition: Then, an RC base paper (155 g / m ² , thickness 151 μm) (Mitsubishi Paper Co., Ltd.) and a thermal transfer image receiving sheet were prepared. Each of the above coating amounts was a solid content, the intermediate layer was 1.5 g / m ² , the receiving layer was 5.0 g / m ² , and the adhesive layer was 5 g / m ² .

<Intermediate layer coating solution>
・ Polyester resin 50 parts (Polyester WR-905 Nippon Synthetic Chemical Industry Co., Ltd.)
・ Titanium oxide 20 parts (TCA888 Tochem Products)
・ Fluorescent brightener 1.2 parts (Ubitex BAC Ciba Specialty Chemicals Co., Ltd.)
Water / isopropyl alcohol = 1/1 28.8 parts

<Coating solution composition for receiving layer>
・ 60 parts of vinyl chloride-vinyl acetate copolymer (Solvine C Nissin Chemical Industry Co., Ltd.)
・ Epoxy-modified silicone 1.2 parts (X-22-3000T Shin-Etsu Chemical Co., Ltd.)
・ Methylstil modified silicone 0.6 part (X-24-510 Shin-Etsu Chemical Co., Ltd.)
・ Methyl ethyl ketone / toluene (mass ratio 1/1) 5 parts

<Coating liquid for adhesive layer>
・ Urethane resin 30 parts (Takelac A-969V Mitsui Takeda Chemical Co., Ltd.)
・ Isocyanate 10 parts (Takenate A-5 Mitsui Takeda Chemical Co., Ltd.)
・ 100 parts of ethyl acetate

Using the thermal transfer sheets of Examples and Comparative Examples obtained above, solid printing in magenta color was performed with a sublimation transfer printer (CW-02) manufactured by Citizen System Co., Ltd. Examined.
The above solid printing is performed at room temperature, and the peelability (releasability) between the dye layer of the thermal transfer sheet and the receiving layer of the thermal transfer image-receiving sheet is evaluated by the following evaluation criteria. did.

(Evaluation criteria for peelability)
◯: There is no portion where the dye layer is peeled off from the thermal transfer sheet to the thermal transfer image receiving sheet.
Δ: There was a slight separation of the dye layer from the thermal transfer sheet to the thermal transfer image-receiving sheet, but this is a level that does not cause any problems in practice.
X: There are places where the thermal transfer sheet and the thermal transfer image-receiving sheet are stuck and not peeled off.

  In the evaluation of releasability of the printed matter, the solid printing is performed at an environmental temperature of 0 ° C. instead of a room temperature environment, and the peelability between the dye layer of the thermal transfer sheet and the receiving layer of the thermal transfer image receiving sheet is determined. The both evaluations were made according to the same evaluation criteria as above by peeling them off by hand.

  In the evaluation of releasability of the printed matter, the solid printing is performed in an environment of high temperature and high humidity of 40 ° C. and humidity of 85% RH, the dye layer of the thermal transfer sheet, the receiving layer of the thermal transfer image receiving sheet, The peelability of the film was evaluated by the same evaluation criteria as above by peeling both of them by hand.

(Evaluation of foam generation prevention from coating liquid)
When preparing each thermal transfer sheet of the above-mentioned Examples and Comparative Examples, when providing a magenta dye layer on a substrate, when applying with a gravure coater at a coating speed of 150 m / min, the magenta dye The layer coating liquid is stirred by the rotation of the roll and bubbles are likely to be generated. The prevention of the bubble generation was evaluated under the following conditions. If there is a lot of foaming in the coating liquid, defects such as streaks occur in the printed matter, so using the thermal transfer sheet obtained under the above coating conditions, the conditions at the time of releasability evaluation under the above room temperature environment, Magenta color solid printing was performed and evaluated according to the following evaluation criteria.

(Evaluation criteria for preventing foam generation)
A: No printing defect is found in the solid printing part.
◯: There was a slight print defect in the solid print part, but it is a level that does not cause any practical problems.
X: There is a serious printing defect in the solid printing part.

Table 1 below shows the evaluation results in the evaluation of the density of the printed matter, the evaluation of releasability after printing, and the evaluation of foam generation prevention.

As shown in the above results, the thermal transfer sheets of Examples 1 to 3 were good results in all of the evaluation of the releasability of the printed matter and the evaluation of the prevention of foam generation from the coating liquid.
In the thermal transfer sheets of Comparative Examples 1 and 2, the evaluation of releasability after printing at an environmental temperature of 0 ° C. was not good, and the evaluation of foam generation prevention was poor.
In the thermal transfer sheets of Comparative Examples 3 and 5, the evaluation of releasability after printing in all environments of room temperature, 0 ° C. and high temperature and high humidity was poor.
In the thermal transfer sheet of Comparative Example 4, the evaluation of releasability after printing in all environments of room temperature, 0 ° C. and high temperature and high humidity was poor, and further, the evaluation of foam generation prevention was poor.

DESCRIPTION OF SYMBOLS 1 Thermal transfer sheet 2 Base material 3 Dye layer 4 Heat resistant slipping layer 5 Dye primer layer

Claims (3)

A thermal transfer sheet provided with a dye layer on one side of a substrate and a heat-resistant slip layer on the other side of the substrate,
The dye layer contains a sublimable dye, a nitrocellulose resin, and a modified silicone having at least one of an alkyl group or an aralkyl group. The sublimable dye of the dye layer contains one or more dyes selected from the group consisting of general formula (1), general formula (2), general formula (3), and general formula (4). The thermal transfer sheet according to claim 1.

R1 and R2 in the general formula (1) are each independently a hydrogen atom, substituted or unsubstituted alkyl group, vinyl group, allyl group, aryl group, alkoxyalkyl group, aralkyl group, alkoxycarbonylalkyl group, carboxyalkyl group. Or an alkoxycarboxyalkyl group, and R 1 and R 2 may form a ring with each other. R3 is hydroxyl group, halogen atom, cyano group, substituted or unsubstituted alkyl group, alkylformylamino group, alkylsulfonylamino group, formylamino group, allylformylamino group, sulfonylamino group, allylsulfonylamino group, carbamoyl group, sulfamoyl Group, amino group, carboxyl group, alkoxy group or ureido group, R4 and R5 are hydrogen atom, halogen atom, cyano group, nitro group, substituted or unsubstituted alkyl group, allyl group, substituted or unsubstituted aryl Group, aralkyl group, alkoxyalkyl group, aralkyloxyalkyl group, thioalkyl group, allyloxyalkyl group, aryloxyalkyl group, carbomoyl group, sulfamoyl group, oxycarbonyl group, amino group, formylamino group, sulfonylamido It represents group, alkoxycarbonylalkyl group, a heterocyclic group, a cycloalkyl group, an alkylthio group, an alkylsulfinyl group or an alkylsulfonyl group.

In general formula (2), R1 and R2 represent an alkenyl group, an aralkyl group, or a substituted or unsubstituted alkyl group, R3 represents a hydrogen atom, a methyl group, a methoxy group, or a halogen atom, and R4 represents a hydrogen atom or a methyl group. Represents a methoxy group, a formylamino group, an alkylcarbonylamino group, an alkylsulfonylamino group, or an alkoxycarbonylamino group, and R5 represents an alkyl group, an alkenyl group, an allyl group, an aryl group, a cyanoalkyl group, a substituted or unsubstituted group. Represents an alkoxycarbonylalkyl group.

X and Y in the general formula (3) in -S -, - O-or -SO ₂ - represents, R1 and R2 represent a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group or an allyl group.

The X in the general formula (4) -S -, - O-or -SO ₂ - represents, R1 represents a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group or an allyl group. The sublimable dye is
In the general formula (1), R1, R2, R3, and R4 are each a substituted or unsubstituted alkyl group, and R5 is a substituted or unsubstituted aryl group,
In the general formula (2), R1 and R2 are alkyl groups, R3 and R4 are hydrogen atoms or alkylcarbonylamino groups, R5 is an alkenyl group,
In the general formula (3), X and Y are —O—, R 1 and R 2 are substituted or unsubstituted aryl groups,
3. The thermal transfer sheet according to claim 2, wherein in the general formula (4), X and Y are —O—, and R 1 is a substituted or unsubstituted aryl group.

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