JP2014065162A - Thermal transfer sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal transfer sheet obtained by providing a dye layer and a thermally transferable protective layer in order on a substrate sheet, which has glossiness and can prevent the appearance of scorch without being thermally fused with a thermal transfer image receiving sheet and matting a printed matter surface.SOLUTION: There is provided a thermal transfer sheet 1 obtained by providing a dye layer 3 and a thermally transferable protective layer 4 in order on a substrate sheet 2. The substrate sheet 2 has a steam permeability of 0.1 g/m. 24 hr/0.1 mm or more and 2 g/m. 24 hr/0.1 mm or less.

Description

  The present invention relates to a thermal transfer sheet in which a dye layer and a thermal transferable protective layer are provided in a surface order on a base sheet.

  Conventionally, a thermal transfer method has been widely used as a simple printing method. The thermal transfer method, which is one of the thermal transfer methods, is a thermal transfer image receiving sheet such as a paper or a plastic sheet. The thermal transfer sheet is provided with a color material such as a pigment and a hot melt ink layer containing a binder such as a hot melt wax or resin. And an image forming method in which energy corresponding to image information is applied from the back side of the thermal transfer sheet by a heating means such as a thermal head to transfer the color material together with the binder onto the thermal transfer image receiving sheet. An image obtained by the melt transfer method has a high density and excellent sharpness, and is suitable for recording binary images such as characters.

  The sublimation transfer method, which is one of the thermal transfer methods, is a thermal transfer image receiving sheet in which a thermal transfer sheet provided with a colorant layer (dye layer) containing a sublimable dye that transfers heat by sublimation is provided on a base sheet. And an image forming method in which energy corresponding to image information is applied from the back side of the thermal transfer sheet by a heating means such as a thermal head to transfer and transfer the sublimation dye onto the thermal transfer image receiving sheet. In this sublimation transfer method, the amount of dye transfer can be controlled in accordance with the amount of energy applied, so that a gradation image can be formed with the image density controlled for each dot of the thermal head. Further, since the color material to be used is a dye, the formed image is transparent, and the reproducibility of intermediate colors when dyes of different colors are superimposed is excellent. Therefore, when using thermal transfer sheets of different colors such as yellow, magenta, cyan, black, etc., and transferring each color dye on the thermal transfer image receiving sheet, high-quality photographic tone full-color images with excellent reproducibility of intermediate colors can be obtained. Formation is possible.

  Due to the development of various hardware and software related to multimedia, this thermal transfer method is a full-color hard copy system for analog images such as digital graphics and video such as still images by computer graphics, satellite communications and CD-ROM. As the market is expanding. The specific applications of the thermal transfer image receiving sheet by this thermal transfer method and the thermal transfer sheet used in combination with the thermal transfer image receiving sheet are diverse. Typical examples include printing proofs, image output, CAD / CAM design and design output, various medical analytical instruments such as CT scans and endoscopic cameras, measuring instrument output applications and instant As an alternative to photos, output of ID cards, ID cards, credit cards, other face photos on cards, etc., as well as composite photos and amusement photos at amusement facilities such as amusement parks, game centers, museums, and aquariums Etc.

  When sublimation transfer-type thermal transfer sheets are used, it is possible to accurately form tonal images such as facial photographs, but the formed images have no vehicle, unlike ordinary printing inks. Since it is formed only with a dye, there is a disadvantage that it is inferior in durability such as weather resistance, friction resistance and chemical resistance. On the other hand, a protective layer thermal transfer sheet having a transferable protective layer is overlaid on the image obtained by thermal transfer of the sublimation dye, and the transferable protective layer is transferred using a thermal head or a heating roll, on the image. A method for forming a protective layer is known. (For example, see Patent Document 1)

  Then, when transferring the protective layer onto the thermal transfer image with the dye, prepare a thermal transfer sheet with a dye layer on the base material and a protective layer thermal transfer sheet with a protective layer on another base material. Attach the thermal transfer sheet with the dye layer on the printer to form a thermal transfer image, then replace the thermal transfer sheet with a protective layer thermal transfer sheet, and heat transfer the protective layer onto the thermal transfer image. However, in order to carry out efficiently, thermal transfer image formation with a dye and transfer of a protective layer are continuously performed using a thermal transfer sheet in which a dye layer and a protective layer are formed in the same order on the same substrate. In order to obtain a printed material with improved durability. (See Patent Document 2)

  In such a thermal transfer recording system using sublimation transfer, as the printing speed of the thermal transfer printer is increased, there has been a problem that a sufficient print density cannot be obtained with the conventional thermal transfer sheet. In addition, there has been a demand for clearer images with higher density than printed images by thermal transfer. On the other hand, a high density portion of black when a black thermal transfer image is formed by sequentially superimposing three colors of dyes from yellow, magenta, and cyan dye layers and finally a protective layer to be transferred from the protective layer transfer sheet. With respect to the image quality, it has started to occur. That is, when the receiving layer of the thermal transfer image-receiving sheet is fused to the dye layer side of the thermal transfer sheet, the hue of the black part changes, and as a result, the surface of the printed material becomes matte and loses glossiness. A phenomenon called “Something Solid” has come to be seen. For this reason, many attempts have been made to improve the thermal transfer sheet and the thermal transfer image receiving sheet. (Patent Document 3 etc.)

  Further, the moisture contained in the thermal transfer sheet evaporates due to heat during printing, and the thermal transfer sheet and the thermal transfer image receiving sheet are thermally fused, and the above-mentioned “burnt” phenomenon may occur. In addition, the above-mentioned “burning” phenomenon is likely to occur due to moisture contained in the primer layer of the thermal transfer sheet.

JP 2003-127558 A Japanese Patent Laid-Open No. 7-276831 JP 2010-234733 A

  Therefore, in order to solve the above-mentioned problems, the object of the present invention is to provide a thermal transfer sheet in which a dye layer and a thermal transferable protective layer are provided in a surface sequence on a base sheet, without being thermally fused to the thermal transfer image receiving sheet. It is an object of the present invention to provide a thermal transfer sheet that has gloss on the surface of a printed material and can prevent the development of kogation.

The above object is achieved by the present invention described below. That is, the present invention is a thermal transfer sheet in which a dye layer and a heat transferable protective layer are provided in a surface sequence on a base sheet, and the base sheet has a water vapor transmission rate of 0.1 g / m ² · 24 hr / 0.1mm or more, and a thermal transfer sheet structure, characterized in that at most ^{2g / m 2 · 24hr / 0.1mm} .

  In the present invention, the base sheet is preferably an aromatic polyamide film.

  According to the thermal transfer sheet of the present invention, the surface of the printed material is not matted without being thermally fused to the thermal transfer image receiving sheet, and glossiness is obtained and the development of kogation can be prevented.

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 thermal transfer sheet 1 has three colors of a yellow dye layer 3Y, a magenta dye layer 3M, and a cyan dye layer 3C on one surface of a base sheet 2. This is a thermal transfer sheet in which the dye layer 3, the thermal transferable protective layer 4 in which the release layer 6 and the protective layer 7 are sequentially laminated are repeatedly provided in the surface order. A heat resistant slipping layer 5 is provided on the other surface of the base sheet 2.

  FIG. 2 shows another embodiment of the thermal transfer sheet of the present invention. The thermal transfer sheet 1 has a dye primer layer on the other side of the base sheet 2 provided with a heat-resistant slip layer 5 on one side. 9 on the dye primer layer 9, a three-color dye layer 3 of a yellow dye layer 3 Y, a magenta dye layer 3 M and a cyan dye layer 3 C, and a black molten ink layer 10 on the release layer 6. In addition, the thermal transfer sheet is provided with a thermal transferable protective layer 4 in which a release layer 6, a protective layer 7, and an adhesive layer 8 are sequentially laminated in a surface sequential manner.

Hereinafter, each layer constituting the thermal transfer sheet 1 will be described in detail.
(Substrate sheet)
The base material sheet 2 satisfies the conditions of water vapor permeability of 0.1 g / m ² · 24 hr / 0.1 mm or more and 2 g / m ² · 24 hr / 0.1 mm or less. The water vapor transmission rate defined in the present invention is all measured in accordance with JIS K7129 using a water vapor transmission rate measuring device (Honeywell Co., Ltd .: W825 type) at a temperature of 40 ° C. and a relative humidity of 90%. It is. This water vapor transmission rate is a numerical value represented by a water vapor transmission amount per 24 hours, a thickness of 0.1 mm, and an area of 1 m ² .

If the water vapor transmission rate is larger than ² g / m ² · 24 hr / 0.1 mm, it is easy to heat-seal with the thermal transfer image-receiving sheet, the surface of the printed material is matted, the glossiness is lowered, and the phenomenon of burnt spots tends to occur. Tend. If the water vapor transmission rate is smaller than 0.1 g / m ² · 24 hr / 0.1 mm, not the thermal transfer sheet but the thermal head tends to be easily damaged during printing.

  As the base sheet, for example, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene terephthalate-isophthalate copolymer, terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer satisfying the above water vapor transmission rate conditions. Polyester films such as polyethylene terephthalate and polyethylene naphthalate coextruded films, aliphatic polyamide films such as nylon 6 and nylon 66, aromatic polyamide films such as Kepler and Nomex, polyethylene, polypropylene, polymethylpentene, etc. Polyolefin film, vinyl film such as polyvinyl chloride, polyacrylate, polymethacrylate, polymethylmethacrylate Any acrylic film, imide film such as polyimide, polyetherimide, polyarylate, polysulfone, polyethersulfone, polyphenylene ether, polyphenylene sulfide (PPS), polyaramide, polyetherketone, polyethernitrile, polyetheretherketone, poly Examples include engineering films such as ether sulfite, styrene films such as polycarbonate, polystyrene, high impact polystyrene, AS resin, and ABS resin, and cellulose films such as cellophane, cellulose acetate, and nitrocellulose.

  The base sheet may be a copolymer resin or a mixture (including an alloy) containing the above resin as a main component, or a laminated sheet composed of a plurality of layers. Moreover, although a base film may be a stretched film or an unstretched film, it is preferable to use a film stretched in a uniaxial direction or a biaxial direction for the purpose of improving strength. Among the above-described substrate sheets made of a resin, an aromatic polyamide film is more preferable because it is excellent in heat resistance, smoothness, mechanical strength, and high-speed printing suitability.

  The aromatic polyamide contains a repeating unit represented by at least one of the following general formula (1) and general formula (2), either alone or by copolymerization, in a form of polymerization of 50 mol% or more, preferably 70 mol% or more. Is desirable.

Here, Ar ₁ , Ar ₂ and Ar ₃ in the general formulas (1) and (2) are, for example, those shown in the following general formula (3), and X and Y are —O— It is selected from, but not limited to, CH ₂ —, —CO—, —SO ₂ —, —S—, —C (CH ₃ ) ₂ — and the like. Furthermore, some of the hydrogen atoms on these aromatic rings are halogen groups such as chlorine, fluorine and bromine (especially chlorine is preferable), alkyl groups such as nitro group, methyl group, ethyl group and propyl group (especially methyl group is Preferred), including those substituted with a substituent such as an alkoxy group such as a methoxy group, an ethoxy group, and a propoxy group, and those in which the hydrogen in the amide bond constituting the polymer is substituted with another substituent Is also included.

  As the base sheet, one having a thickness of about 2.5 μm to 50 μm is usually used, but a base sheet having a thickness of 2.5 μm to 25 μm can be more suitably used. If the thickness of the base sheet is less than 2.5 μm, the mechanical strength may be insufficient and the dye layer, the protective layer, etc. may not be supported. On the other hand, when the thickness of the substrate sheet exceeds 50 μm, although the mechanical strength is high, the transfer of thermal energy when transferring the dye from the dye layer of the thermal transfer sheet becomes insufficient, and the transfer sensitivity tends to decrease. On the other hand, when the thickness of the substrate exceeds 50 μm, the transfer of thermal energy when transferring the thermal transferable protective layer from the thermal transfer sheet becomes insufficient and the transferability tends to be lowered.

  In the case where a release layer is provided on the surface of the base sheet, a corona discharge treatment, a plasma treatment, an ozone treatment, a flame treatment, a primer (an anchor coat, an adhesion promoter, and an easy-adhesive agent) are previously provided on the surface on which the release layer is provided. An easy adhesion treatment such as a coating treatment, a pre-heat treatment, a dust removal treatment, a vapor deposition treatment, and an alkali treatment may be performed.

(Dye layer)
The dye layer 3 formed on the base sheet is a layer containing a sublimable dye. As the sublimation dye, any dye conventionally used in known thermal transfer sheets can be used in the present invention and is not particularly limited. These dyes include methines such as diarylmethane, triarylmethane, thiazole and merocyanine, indoaniline, azomethine such as acetophenone azomethine, pyrazoloazomethine, imidazole azomethine and pyridone azomethine, xanthene and oxazine. Cyanomethylene, thiazine, azine, acridine, benzeneazo, and pyridoneazo, thiophenazo, isothiazole azo, pyrrole azo, pyrazole azo, imidazole azo, thiadiazole azo, triazole azo represented by dicyanostyrene and tricyanostyrene Azo, such as, disazo, spiropyran, indolinospiropyran, fluoran, rhodamine lactam, naphthoquinone, anthraquinone, quinophthalone It is. Specifically, the following dyes are used.

C. I. (Color Index) Disperse Yellow 51, 3, 54, 79, 60, 23, 7, 141, 201, 231
C. I. Disperse Blue 24, 56, 14, 301, 334, 165, 19, 72, 87, 287, 154, 26, 354
C. I. Disperse thread 135, 146, 59, 1, 73, 60, 167
C. I. Disperse Orange 149
C. I. Disperse violet 4, 13, 26, 36, 56, 31
C. I. Solvent Yellow 56, 14, 16, 29
C. I. Solvent Blue 70, 35, 63, 36, 50, 49, 111, 105, 97, 11
C. I. Solvent Red 135, 81, 18, 25, 19, 23, 24, 143, 146, 182
C. I. Solvent Violet 13
C. I. Solvent Black 3
C. I. Solvent Green 3

  For example, Foron brilliant yellow S-6GL (Sand, Disperse Yellow 231), Macrolex Yellow 6G (Bayer, Disperse Yellow 201) as a yellow dye, and MS-RED-G (Mitsui Toatsu Chemical Co., Ltd.) as a magenta dye Company, Disper Thread 60), Macrolex Red Violet R (manufactured by Bayer, Dispers Violet 26), cyan dye is Kayaset Blue 714 (Nippon Kayaku Co., Ltd., Solvent Blue 63), Foron Brilliant Blue S-R (Sand, Disperse Blue 354), Waxoline Blue AP-FW (ICI, Solvent Blue 36) and the like.

  Next, as a binder resin for carrying the above dye, cellulose resins such as ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, acetic acid / butyric acid cellulose, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl Examples include vinyl resins such as acetoacetal and polyvinylpyrrolidone, acrylic resins such as poly (meth) acrylate and poly (meth) acrylamide, polyurethane resins, polyamide resins, and polyester resins. Among these, cellulose , Polyurethane-based, vinyl-based, acrylic-based and polyester-based resins are preferably used in terms of heat resistance, dye transferability and the like.

The dye layer is added to one side of the base sheet with these dyes and binder resin, and additives (for example, release agents, etc.) and fillers as necessary, and then toluene, methyl ethyl ketone, ethanol, isopropyl alcohol. , Dissolved in a suitable organic solvent such as cyclohexanone or DMF, or dispersed in an organic solvent or water, and applied and dried by means of gravure printing, screen printing, reverse roll coating printing, etc. A film can be formed. Dye layer formed in this way, in the coating amount in thickness, in the dry ^{state, 0.2g / m 2 ~5.0g / m} 2 preferably 0.4g / m ² ~2.0g / m ² The sublimable dye in the dye layer should be present in an amount of 5% to 90% by weight, preferably 10% to 70% by weight, based on the total weight of the dye layer. If the desired dye layer image is monochromatic, select one of the dye layers such as yellow, magenta, cyan, etc., and if it is a full color image, appropriate yellow, magenta, and cyan Select and form each dye layer (add black as needed).

(Dye primer layer)
By providing the dye primer layer 9 between the base material sheet and the dye layer, the adhesion between the base material sheet and the dye layer is improved, and the thermal fusion between the dye layer of the thermal transfer sheet and the thermal transfer image receiving sheet during printing is performed. Wear can be prevented more preferably.
The dye primer layer can be composed of an adhesive component that can enhance the adhesion between the dye layer and the substrate sheet. In order to solve the problems of the present invention, the point that the thermal transfer image-receiving sheet is easily heat-sealed, the surface of the printed material is likely to be matted, the gloss is liable to be lowered, and the tendency of the kogation phenomenon is easily generated. It is preferable that the dye primer layer mainly contains a polyvinyl pyrrolidone resin.

  Since this polyvinyl pyrrolidone resin is the main component, not only is it easy to prevent thermal fusion with the thermal transfer image-receiving sheet, but also the transfer sensitivity during thermal transfer is greatly improved and high energy can be applied without applying high energy. A density thermal transfer image is obtained. Further, by mixing an adhesive component in addition to the polyvinyl pyrrolidone resin in the dye primer layer, the adhesion between the dye layer and the substrate sheet can be improved, and abnormal transfer or the like can be prevented.

  Examples of the polyvinyl pyrrolidone resin include homopolymers of vinyl pyrrolidone such as N-vinyl-2-pyrrolidone and N-vinyl-4-pyrrolidone, and copolymers thereof. The polyvinyl pyrrolidone resin used in the dye primer layer preferably has a K value in the Fickencher formula of 60 or more, and in particular, a grade of K-60 to K-120 can be used. It is about 30,000 to 280,000. When the polyvinyl pyrrolidone resin having a K value of less than 60 is used, the effect of improving transfer sensitivity in printing is reduced.

  The dye primer layer can be mixed with an adhesive component in addition to the polyvinyl pyrrolidone resin to improve the adhesion between the substrate sheet and the dye layer. The adhesive components include polyester resin, polyacrylate resin, polyvinyl acetate resin, polyurethane resin, styrene acrylate resin, polyacrylamide resin, polyamide resin, polyether resin, polystyrene resin, polyethylene resin, polypropylene resin, polyvinyl chloride. Examples thereof include vinyl resins such as resins, vinyl chloride-vinyl acetate copolymer resins and ethylene-vinyl acetate copolymer resins, and polyvinyl acetal resins such as polyvinyl acetoacetal and polyvinyl butyral. As the adhesive component, polyester resin, polyurethane resin, and acrylic resin are particularly preferable because of strong adhesiveness.

The dye primer layer is prepared by preparing a gravure printing method, a screen printing method, a gravure plate by adjusting a coating solution obtained by dissolving or dispersing the above-mentioned materials and other additives in an organic solvent or an aqueous solvent. It can form using well-known coating means, such as the used reverse roll coating method. Dye primer layer formed in this way, in the coating amount in thickness, in the dry state, which is 0.01g / m ² ~3.0g / m ² a thickness of about.

(Molten ink layer)
A molten ink layer having a hue such as black may be provided on the other surface of the base sheet on which the heat-resistant slip layer is provided. The molten ink layer can be composed of a colorant and a vehicle, and various additives are added as necessary. As the colorant, among organic or inorganic pigments or dyes, those having a color density required as a recording material and not discolored by light, heat, temperature or the like are preferable. In addition, a substance that develops color when heated or a substance that develops color when brought into contact with a substance applied to the transfer medium can also be used. In addition to black, various colorants such as cyan, magenta, and yellow can be used as the colorant.

The vehicle is mainly composed of a wax, and in addition, a mixture of a wax and a drying oil, resin, mineral oil, cellulose, rubber derivatives, or the like is used. Moreover, in order to give favorable heat conductivity and melt transferability, the heat conductive substance can be contained in the melt ink layer formed from heat melt color ink. Examples of such a heat conductive material include carbonaceous materials such as carbon black, aluminum, copper, tin oxide, and molybdenum disulfide. Examples of a method for forming a molten ink layer on a substrate sheet using the above-described hot-melt coloring ink include known methods such as hot melt coating, hot lacquer coating, gravure coating, gravure reverse coating, and roll coating. It is done. The thickness of the molten ink layer, the required print density is, considering the heat sensitivity and the like can be appropriately determined, it is ^{usually, 0.1g / m 2 ~30g / m} 2 approximately at the time of drying.

(Thermal transfer protective layer)
On the base material sheet, the heat transferable protective layer 4 is detachably formed. If the thermal transferable protective layer can be thermally transferred from the thermal transfer sheet to the transfer medium by heating with a thermal head or the like, it can be composed of only the protective layer. Moreover, in order to improve the transfer property from a base material sheet, it can be set as the structure laminated | stacked in order of the peeling layer 6 and the protective layer 7 from the base material sheet side. Further, when the thermal transferable protective layer is transferred to the transfer target, the adhesive layer 8 can be provided on the protective layer in order to improve the adhesion to the transfer target.

Examples of the binder resin for the protective layer 7 used in the present invention include polyester resin, polyester urethane resin, polycarbonate resin, acrylic resin, ultraviolet ray absorbing resin, epoxy resin, acrylic urethane resin, and resins obtained by modifying these resins with silicone. And a mixture of these resins, an actinic ray curable resin, and the like. The actinic ray means a ray that chemically acts on the actinic ray curable resin to promote polymerization, and specifically, visible ray, ultraviolet ray, X-ray, electron beam, α ray, β Means line, gamma ray, etc.
Especially, in this invention, polyester-type resins, such as a polyester resin and a polyester urethane resin, can be used conveniently. The polyester resin or polyester urethane resin may be a copolymer with another thermoplastic resin.

  Although there is no limitation in particular about content of the binder resin which comprises a protective layer, when content of binder resin is less than 20 mass% with respect to the solid content total amount of a protective layer, foil cutting property and durability will fall. Tend to. Therefore, considering this point, the binder resin is preferably contained in an amount of 20% by mass or more, and more preferably 30% by mass or more, based on the total solid content of the protective layer. Although there is no limitation in particular about the upper limit of content of binder resin, the upper limit is 100 mass%.

  As the ultraviolet absorbing resin, for example, a resin obtained by reacting and bonding a reactive ultraviolet absorber to a thermoplastic resin or the above-mentioned actinic ray curable resin can be used. More specifically, addition-polymerizable double-reactive organic UV absorbers such as salicylates, benzophenones, benzotriazoles, substituted acrylonitriles, nickel chelates, hindered amines, etc. Examples thereof include a bond (for example, a vinyl group, an acryloyl group, a methacryloyl group, etc.), an alcoholic hydroxyl group, an amino group, a carboxyl group, an epoxy group, and a reactive group such as an isocyanate group.

In addition to the binder resin, the protective layer may contain other materials such as various fillers, fluorescent brightening agents, and ultraviolet absorbers for improving weather resistance.
The protective layer can be provided on the base sheet with the thermoplastic resin described above as a main component, and the protective layer can be formed of only one layer, but can be formed of two or more layers. In this case, the plurality of protective layers can be formed of a coating liquid mainly composed of the same thermoplastic resin, or can be formed of a coating liquid mainly composed of different thermoplastic resins. When the protective layer has three layers, for example, two layers are formed with a coating liquid mainly composed of the same thermoplastic resin, and the remaining one layer is formed with a coating liquid mainly composed of a different thermoplastic resin. Alternatively, all three layers may be formed of a coating liquid mainly composed of the same thermoplastic resin, or all three layers may be formed of a coating liquid mainly composed of different thermoplastic resins.

The protective layer is mainly composed of the above-mentioned thermoplastic resin, dissolved or dispersed in an appropriate organic solvent to prepare a protective layer coating solution, and this is prepared as a base sheet (if necessary on the base sheet) It can be formed by coating and drying on the provided release layer) by a conventionally known means such as a gravure printing method, a screen printing method or a reverse coating method using a gravure plate. The thickness of the protective layer is preferably 2g / m ² ~15g / m ² in a dry state in the configuration conditions of only one layer. When the thickness of the protective layer is less than 2 g / m ² , the durability tends to decrease. On the other hand, when the thickness of the protective layer is greater than 15 g / m ² , the foil breakability of the protective layer is reduced. This is likely to cause creaking or the like when the thermal transferable protective layer is thermally transferred to the transfer target.

(Peeling layer)
In the thermal transfer sheet of the present invention, a release layer 6 can be provided between the substrate sheet and the protective layer so that the thermal transferable protective layer can be easily released from the substrate sheet during thermal transfer. The release layer is a layer that is transferred onto the transfer target during thermal transfer.
Examples of the release layer material include cellulose derivatives such as ethyl cellulose, nitrocellulose, and cellulose acetate, acrylic resins such as polymethyl methacrylate, polyethyl methacrylate, and polybutyl acrylate, polyvinyl chloride, and vinyl chloride-vinyl acetate. Thermosetting resins such as copolymers, thermoplastic resins of vinyl copolymers such as polyvinyl butyral, saturated or unsaturated polyester resins, polyurethane resins, thermally crosslinkable epoxy-amino resins, amino alkyd resins, silicone waxes, Examples thereof include a silicone resin, a silicone-modified resin, a fluorine resin, a fluorine-modified resin, and polyvinyl alcohol. The release layer preferably contains a filler such as microsilica or polyethylene wax in order to improve the foil breakability. Further, the release layer may be made of one kind of resin, or may be made of two or more kinds of resins. The release layer may be formed using a crosslinking agent such as an isocyanate compound, a catalyst such as a tin-based catalyst, and an aluminum-based catalyst in addition to the resin exemplified above.

The release layer that is formed as necessary is obtained by dispersing or dissolving the above resin in a solvent and coating it on at least a part of the base sheet by a known coating method such as roll coating, gravure coating, or bar coating. It can be formed by drying. The thickness of the release layer, typically has a thickness in 0.1g / m ² ~5g / m ² approximately after drying, preferably 0.5g / m ² ~2g / m ² approximately.

(Adhesive layer)
In the present invention, when the thermal transferable protective layer has sufficient adhesion to the transfer target, it is not necessary to form the adhesive layer. However, the adhesive layer 8 is formed on the surface of the thermal transferable protective layer, and the thermal transferability is achieved. The transferability of the protective layer and the adhesion of the protective layer after transfer to the image surface can be improved, which is preferably performed. As the adhesive layer, any conventionally known heat-sensitive adhesive can be used, but it is more preferably formed from a thermoplastic resin having a glass transition temperature of 50 ° C. to 100 ° C., for example, an ultraviolet absorbing resin, an acrylic resin, a chloride Select a resin with an appropriate glass transition temperature from resins with good thermal adhesive properties such as vinyl-vinyl acetate copolymer resin, epoxy resin, polyester resin, polycarbonate resin, butyral resin, polyamide resin, vinyl chloride resin, etc. It is preferable to do.

For the adhesive layer, one or a plurality of resin materials selected from the materials exemplified above, and if necessary, additives are added and dissolved or dispersed in an appropriate solvent such as an organic solvent. A coating solution can be prepared, and this can be formed by coating and drying by means of a gravure printing method, a screen printing method or a reverse coating method using a gravure plate. Is not particularly limited thickness of the adhesive layer is ^{usually, 1g / m 2 ~10g / m} 2 approximately in a dry state.

(Heat resistant slipping layer)
The thermal transfer sheet of the present invention prevents adverse effects such as sticking and wrinkles due to thermal head heat on the back side of the base sheet, that is, the side opposite to the side where the thermal transferable protective layer is provided. The heat-resistant slipping layer 5 can be provided in order to improve the property and improve the transportability. The resin for forming the heat-resistant slipping layer may be any conventionally known resin such as polyvinyl butyral resin, polyvinyl acetoacetal resin, polyester resin, vinyl chloride-vinyl acetate copolymer, polyether resin, polybutadiene. Resin, styrene-butadiene copolymer, acrylic polyol, polyurethane acrylate, polyester acrylate, polyether acrylate, epoxy acrylate, urethane or epoxy prepolymer, nitrocellulose resin, cellulose nitrate resin, cellulose acetopropionate resin, cellulose acetate Butyrate resin, cellulose acetate hydrodiene phthalate resin, cellulose acetate resin, aromatic polyamide resin, polyimide resin, polyamideimide resin, polycarbonate Boneto resins, and chlorinated polyolefin resins.

  The slipperiness imparting agent added to or overcoated with the heat resistant slipping layer made of these resins includes phosphate ester, silicone oil, graphite powder, silicone graft polymer, fluorine graft polymer, acrylic silicone graft polymer, acrylic siloxane, aryl Examples thereof include silicone polymers such as siloxane, but a layer made of a polyol, for example, a polyalcohol polymer compound, a polyisocyanate compound, and a phosphate ester compound, and a filler is more preferably added.

The heat resistant slipping layer is prepared by dissolving or dispersing the above-described resin, slipperiness imparting agent, and filler with an appropriate solvent to prepare a heat resistant slipping layer forming ink. It can apply | coat to the back surface of a material sheet | seat by forming means, such as the reverse coating method using a gravure printing method, a screen printing method, and a gravure plate, and can dry and form. The coating amount of the heat-resistant lubricating layer is sufficient as long as the anti-fusing and slipping, and the fulfill is usually 0.1g / m ² ~3g / m ² approximately at the time of drying.

By using a base material sheet having a water vapor transmission rate of 0.1 g / m ² · 24 hr / 0.1 mm or more and 2 g / m ² · 24 hr / 0.1 mm or less as defined in the present invention, it is contained in the thermal transfer sheet. Since the water content is in an appropriate range, the printed image surface is not matted without being thermally fused to the thermal transfer image-receiving sheet during printing, and it is possible to have gloss and prevent the development of kogation. Furthermore, the thermal transfer sheet of the present invention, which is a thermal transfer sheet provided with a dye layer on a base material sheet and in which the thermal transfer protective layer is integrally provided on the base material sheet, is a thermal transfer image by dye to a transfer target. After forming, etc., it is possible to form a printed matter by transferring the protective layer on the thermal transfer image without preparing another thermal transfer sheet provided with a protective layer on the base sheet, which is efficient and very useful. Is.

Next, the present invention will be described more specifically with reference to examples. Hereinafter, unless otherwise specified, parts or% is based on mass.
Example 1
An aromatic polyamide film (Mikutron manufactured by Toray Industries, Inc.) having a thickness of 4 μm is used as the base sheet 2 and a heat resistant slipping layer forming coating liquid having the following composition is used on one side of the base sheet. By a coater method, the film was coated and dried to a thickness of 1.0 g / m ² after drying to form a heat resistant slipping layer.

<Coating fluid for forming heat resistant slipping layer>
・ 4.55 parts of polyvinyl butyral resin (ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.)
Polyisocyanate 21.0 parts (Bernock D750-45, solid content 45% by mass, manufactured by Dainippon Ink & Chemicals, Inc.)
・ 3.0 parts of phosphate ester surfactant (Pricesurf A208N, manufactured by Daiichi Pharmaceutical Co., Ltd.)
・ Metal soap (LBT1830, manufactured by Sakai Chemical Industry Co., Ltd.) 0.45 part ・ Talc (Microace P-3, manufactured by Nihon Talc Industry Co., Ltd.) 0.3 part ・ Methyl ethyl ketone 100.0 parts ・ Toluene 100.0 Part

On the side opposite to the surface on which the heat-resistant slip layer of the base material sheet is provided, a coating solution for yellow, magenta and cyan dye layers having the following composition is used, and 1.0 g / m ^{2 in} terms of solid content. In the arrangement shown in FIG. 1, the yellow, magenta and cyan dye layers were formed by coating and drying by the bar coater method.

<Coating solution for yellow dye layer>
Disperse dye (holon brilliant yellow-S-6GL) 5.5 parts Binder resin 4.5 parts (polyvinyl acetoacetal resin KS-5, manufactured by Sekisui Chemical Co., Ltd.)
・ Phosphate surfactant 0.1 part (Pricesurf A208N, manufactured by Daiichi Pharmaceutical Co., Ltd.)
・ Polyethylene wax 0.1 part ・ Methyl ethyl ketone 45.0 parts ・ Toluene 45.0 parts

<Coating liquid for magenta dye layer>
-Disperse dye (MS Red G) 1.5 parts-Disperse dye (Macrolex Red Violet R) 2.0 parts-Binder resin 4.5 parts (polyvinylacetoacetal resin KS-5, manufactured by Sekisui Chemical Co., Ltd.)
・ Phosphate surfactant 0.1 part (Pricesurf A208N, manufactured by Daiichi Pharmaceutical Co., Ltd.)
・ Polyethylene wax 0.1 part ・ Methyl ethyl ketone 45.0 parts ・ Toluene 45.0 parts

<Cyan dye layer coating solution>
-Disperse dye (Kayaset Blue 714) 4.5 parts-Binder resin (polyvinyl acetoacetal resin KS-5, manufactured by Sekisui Chemical Co., Ltd.) 4.5 parts-Phosphate ester surfactant 0.1 parts ( Price Surf A208N (Daiichi Pharmaceutical Co., Ltd.)
・ Polyethylene wax 0.1 part ・ Methyl ethyl ketone 45.0 parts ・ Toluene 45.0 parts

On the side opposite to the surface on which the heat-resistant slip layer of the base sheet is provided, using a release layer coating liquid having the following composition, a thickness of 1.0 g / m ^{2 in} terms of solid content, FIG. With the arrangement shown, coating and drying were performed by a bar coater method to form a release layer.
<Coating liquid for release layer>
・ 20 parts of polymethyl methacrylate resin (Dianar BR-87, manufactured by Mitsubishi Rayon Co., Ltd.)
・ Toluene 40 parts ・ Methyl ethyl ketone 40 parts

On the above release layer, using a protective layer-forming coating solution having the following composition, the coating is applied by the bar coater method in the arrangement shown in FIG. 1 at a thickness of 2.0 g / m ^{2 in} terms of solid content. The film was dried to form a protective layer, and the thermal transfer sheet of Example 1 was produced.
<Protective layer forming coating solution>
・ 100 parts of vinyl chloride-vinyl acetate copolymer (Solvine (registered trademark) CNL, manufactured by Nissin Chemical Industry Co., Ltd.)
・ Toluene 200 parts ・ Methyl ethyl ketone 200 parts

(Example 2)
In the thermal transfer sheet produced in Example 1, on the side opposite to the surface provided with the heat resistant slipping layer, a coating solution 1 for dye primer layer having the following composition was used, and the thickness was 0.5 g / m ^{2 in} terms of solid content. The dye primer layer was formed by coating and drying by the bar coater method.
<Dye primer layer coating solution 1>
・ Polyvinylpyrrolidone resin (K-90, manufactured by ISP) 6 parts ・ Water 47 parts ・ Isopropyl alcohol 47 parts

(Example 3)
A thermal transfer sheet was prepared in Example 3 in the same manner as in Example 2, except that the dye primer layer coating solution 1 used in Example 2 was changed to the dye primer layer coating solution 2 having the following composition.
<Dye primer layer coating solution 2>
-Polyvinylpyrrolidone resin (K-90, manufactured by ISP) 5.7 parts-Polyurethane resin 0.3 parts (Superflex 460S, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
・ 47 parts of water ・ 47 parts of isopropyl alcohol

Example 4
Using a base sheet of an aromatic polyamide film (Mikutron manufactured by Toray Industries, Inc.) having a thickness of 4 μm provided with a heat-resistant slip layer prepared in Example 1, the surface of the base sheet provided with the heat-resistant slip layer; On the opposite side, a dye primer layer was formed at a thickness of 0.5 g / m ^{2 in} terms of solid content using the dye primer layer coating solution 2 used in Example 3. On the dye primer layer, using the yellow, magenta and cyan dye layer coating liquids used in Example 1, the arrangement shown in FIG. 2 at a rate of 1.0 g / m ^{2 in} terms of solid content. Then, coating was carried out by a bar coater method, followed by drying to form yellow, magenta and cyan dye layers. Furthermore, using the coating liquid for the release layer used in Example 1, the coating composition was dried by the bar coater method at a thickness of 1.0 g / m ^{2 in} terms of solid content and arranged as shown in FIG. The release layer is formed, and the arrangement shown in FIG. 2 is formed on the release layer with a thickness of 3.0 g / m ^{2 in} terms of solid content using a coating solution for forming a black molten ink layer having the following composition. Then, coating and drying were performed by the bar coater method to form a black molten ink layer.

<Black melt ink layer forming coating liquid>
・ Acrylic-vinyl chloride-vinyl acetate copolymer resin 20 parts ・ Carbon black 10 parts ・ Toluene 35 parts ・ Methyl ethyl ketone 35 parts

On the side opposite to the surface on which the heat-resistant slip layer of the base material sheet is provided, the release layer coating liquid used in Example 1 is used on the above-described dye primer layer, and is converted to 1. The release layer was formed by coating and drying by the bar coater method at a thickness of 0 g / m ^{2 and} the arrangement shown in FIG.
On the above release layer, using the protective layer forming coating solution used in Example 1, with a thickness of 2.0 g / m ^{2 in} terms of solid content, the arrangement shown in FIG. Coating and drying were carried out to form a protective layer, and a thermal transfer sheet of Example 2 was produced.

(Comparative Example 1)
A thermal transfer sheet of Comparative Example 1 was produced in the same manner as in Example 1 except that the base sheet was changed to a polyethylene terephthalate film having a thickness of 4.0 μm (product name, Lumirror, manufactured by Toray Industries, Inc.).

(Comparative Example 2)
A thermal transfer sheet of Comparative Example 2 was produced in the same manner as in Example 4 except that the base sheet was changed to a polyethylene terephthalate film having a thickness of 4.0 μm (product name, Lumirror, manufactured by Toray Industries, Inc.).

(Formation of prints)
Using a digital photo printer CX (manufactured by Citizen Systems Co., Ltd.) equipped with a commercially available thermal head, using the dedicated thermal transfer image receiving sheet for the printer and the thermal transfer sheets of the above examples and comparative examples, A thermal transfer image was formed with a test pattern including a portion and a non-printed portion, and each printed matter was produced.

Regarding the thermal transfer sheets of Examples and Comparative Examples, water vapor transmission rate and releasability, and the printed matter formed by each thermal transfer sheet were examined for kogation. Each measurement or evaluation is as follows.
<Water vapor transmission rate>
In each of the thermal transfer sheets of Examples and Comparative Examples prepared above, the water vapor transmission rate of the base sheet used was based on JIS K7129, using a water vapor transmission rate measuring device (Honeywell Co., Ltd. product: W825 type), Measurement was performed under conditions of a temperature of 40 ° C. and a relative humidity of 90%.

<Releasability>
When the thermal transfer sheets of Examples and Comparative Examples were subjected to thermal transfer image formation on the thermal transfer image receiving sheet, the releasability with the thermal transfer image receiving sheet was visually examined under the above-mentioned print formation conditions. The results were evaluated according to the following criteria.

<Evaluation criteria>
3 ... Smooth release from the thermal transfer image-receiving sheet, which is good.
2. Although there is a little resistance to the thermal transfer image receiving sheet, it is released. Almost good.
1 ... It is difficult to release from the thermal transfer image receiving sheet, and a dye layer is taken on the receiving layer of the thermal transfer image receiving sheet, which is defective.

  With respect to the prints obtained with the thermal transfer sheets of Examples and Comparative Examples under the above-mentioned print formation conditions, the kogation was visually examined. The results were evaluated according to the following criteria.

<Evaluation criteria>
3: No kogation is observed in the printed material, which is good.
2 ... A part of the print has a tendency to burnt, but it is almost satisfactory.
1: The printed material has noticeable kogation and is defective.

Table 1 shows the measurement results and evaluation results of the water vapor transmission rate, releasability, and kogation.

As described above, in the thermal transfer sheets of Examples 1 to 4, the base sheet used had a water vapor permeability of 0.1 g / m ² · 24 hr / 0.1 mm or more and 2 g / m ² · 24 hr / 0.1 mm or less. Yes, the releasability from the thermal transfer image-receiving sheet was good, and the appearance of kogation was prevented, which was good. Further, the thermal transfer sheets of Examples 2 to 4 had better release properties than the thermal transfer sheet of Example 1. On the other hand, in the thermal transfer sheets of Comparative Examples 1 and 2, the water vapor permeability of the used base sheet is in the range of 0.1 g / m ² · 24 hr / 0.1 mm or more and 2 g / m ² · 24 hr / 0.1 mm or less. It was outside, the releasability from the thermal transfer image receiving sheet was poor, and a kogation phenomenon occurred.

DESCRIPTION OF SYMBOLS 1 Thermal transfer sheet 2 Base material sheet 3 Dye layer 4 Thermal transferable protective layer 5 Heat resistant slipping layer 6 Release layer 7 Protective layer 8 Adhesive layer 9 Dye primer layer 10 Black melted ink layer

Claims (2)

A thermal transfer sheet in which a dye layer and a heat transferable protective layer are provided in a surface sequence on a substrate sheet,
The thermal transfer sheet, wherein the base material sheet has a water vapor transmission rate of 0.1 g / m ² · 24 hr / 0.1 mm or more and 2 g / m ² · 24 hr / 0.1 mm or less.   The thermal transfer sheet according to claim 1, wherein the base sheet is an aromatic polyamide film.

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