JP2017065032A - Thermal transfer sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal transfer sheet capable of obtaining a printed matter having high brightness, compared to a conventionally known thermal transfer sheet having a metal ink layer.SOLUTION: In a thermal transfer sheet 100 which has a base material 1 and a transfer layer 20 provided so as to be peeled from the base material 1, the transfer layer 20 includes an intermediate layer 5 and a metal ink layer 7, the metal ink layer 7 contains metal powder and a solvent-based resin, and the intermediate layer 5 contains an aqueous resin.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a thermal transfer sheet.

  Conventionally, image information is applied to a heating device such as a thermal head using a thermal transfer sheet in which a hot-melt ink layer in which a color material such as pigment is dispersed in a binder such as a heat-melting wax or resin is supported on a substrate. There is known a hot-melt transfer method in which energy according to the above is applied and a color material is transferred together with a binder onto a transfer paper such as paper or a plastic sheet. An image formed by the melt transfer method has high density and excellent sharpness, and is suitable for recording binary images such as characters and line drawings. In addition, there is a high market demand for easily obtaining a printed matter having a metallic luster using a melt transfer method. For example, Patent Document 1 discloses a release layer, a deposition anchor layer, and a metal deposition on one surface of a substrate. A thermal transfer recording medium in which a layer and an adhesive layer are sequentially provided is proposed. According to the thermal transfer recording medium proposed in Patent Document 1, it is said that a printed matter having high luminance and excellent visibility can be obtained.

  However, in the above configuration using a metal vapor deposition layer, equipment such as a sputtering apparatus is required to obtain the metal vapor deposition layer. Further, since the metal vapor deposition layer itself has no adhesiveness, it is necessary to provide a vapor deposition anchor layer between the release layer and the metal vapor deposition layer, and there is a problem that the manufacturing process becomes complicated as a whole. On the other hand, Patent Document 2 proposes a thermal transfer sheet in which a metallic gloss layer transfer region is formed by laminating a release layer and a metal ink layer on a base material sheet. In this thermal transfer sheet, a release layer coating solution containing a binder resin (for example, acrylic resin, vinyl chloride-vinyl acetate copolymer resin), polyethylene wax, and a solvent (for example, methyl ethyl ketone, toluene) is applied onto a base sheet. A metal ink layer containing an aluminum powder, a binder resin (for example, acrylic resin, vinyl chloride-vinyl acetate copolymer resin), and a solvent (for example, methyl ethyl ketone, toluene) is formed on the release layer. It is manufactured by applying a coating liquid to form a metal ink layer. According to the manufacturing method proposed in Patent Document 2, a thermal transfer sheet including a metal ink layer can be manufactured by a relatively simple method.

JP 63-290789 A JP 2009-83146 A

  By the way, the brightness of a printed matter obtained using a conventionally known thermal transfer sheet (for example, the thermal transfer sheet of Patent Document 2) provided with a metal ink layer is transferred to the metal vapor-deposited layer (for example, the metal vapor-deposited layer of Patent Document 1). Therefore, it is desired to improve the brightness of a print obtained using a thermal transfer sheet having a metal ink layer.

  The present invention has been made in view of such a situation, and it is a main object to provide a thermal transfer sheet capable of obtaining a printed matter with high brightness as compared with a conventionally known thermal transfer sheet having a metal ink layer. And

  The present invention for solving the above problems is a thermal transfer sheet having a base material and a transfer layer provided so as to be peelable from the base material, wherein the transfer layer is directly connected to the intermediate layer and the intermediate layer. A metal ink layer that is in contact with each other, wherein the metal ink layer contains a metal powder and a solvent-based resin, and the intermediate layer contains a water-based resin. It is characterized by.

  In the thermal transfer sheet, the intermediate layer has a laminated structure in which a release layer and a barrier layer are laminated in this order, and the barrier layer is in direct contact with the metal ink layer, and the barrier layer May contain an aqueous resin. Further, the water-based resin may be any one of a water-soluble resin, an emulsion resin, and a dispersion resin.

  Further, the present invention for solving the above problems is a thermal transfer sheet having a base material and a transfer layer provided so as to be peelable from the base material, the transfer layer comprising an intermediate layer and the intermediate layer A metal ink layer that is in direct contact with the metal ink layer, the metal ink layer contains metal powder and a water-based resin, and the intermediate layer contains a solvent-based resin. It is characterized by being.

  In the thermal transfer sheet, the intermediate layer has a laminated structure in which a release layer and a barrier layer are laminated in this order, and the barrier layer is in direct contact with the metal ink layer, and the barrier layer May contain a solvent-based resin.

  According to the thermal transfer sheet of the present invention, it is possible to obtain a printed matter having a high luminance as compared with a conventionally known thermal transfer sheet having a metal ink layer.

It is a schematic sectional drawing which shows an example of the thermal transfer sheet of this invention. It is a schematic sectional drawing which shows an example of the thermal transfer sheet of this invention.

<< The Thermal Transfer Sheet of One Embodiment >>
Hereinafter, a thermal transfer sheet 100 according to an embodiment of the present invention (hereinafter referred to as a thermal transfer sheet according to an embodiment) will be described. As shown in FIG. 1 and FIG. 2, the thermal transfer sheet 100 of one embodiment is provided with a transfer layer 20 on one surface of a base material 1 so as to be peelable from the base material 1. Has a laminated structure in which an intermediate layer 5 and a metal ink layer 7 in direct contact with the intermediate layer 5 are laminated. The base material 1, the intermediate layer 5, and the metal ink layer 7 are essential components in the thermal transfer sheet 100 of one embodiment. The intermediate layer 5 constituting the transfer layer 20 may have a single-layer configuration composed of one layer as shown in FIG. 1, or a laminated configuration in which two or more layers are laminated as shown in FIG. May be present. In the form shown in FIG. 2, the intermediate layer 5 has a laminated structure in which the peeling layer 3 and the barrier layer 4 are laminated in this order from the substrate 1 side.

  In the thermal transfer sheet 100 according to one embodiment, the metal ink layer 7 contains metal powder and a solvent-based resin, and the intermediate layer 5 that is in direct contact with the metal ink layer 7 includes a water-based resin. It is characterized by containing. In this case, when the intermediate layer 5 is composed of two or more layers, the layer (the barrier layer 4 in the embodiment shown in FIG. 2) that directly contacts the metal ink layer 7 among the two or more layers. Contains water-based resin. According to the thermal transfer sheet of one embodiment having the above characteristics, a printed matter with high brightness can be obtained as compared with a conventionally known thermal transfer sheet having a metal ink layer.

  The term “aqueous resin” as used herein refers to a water-soluble resin that is soluble in an “aqueous solvent” or a resin that is insoluble in an “aqueous solvent” but can be dispersed in an aqueous solvent, such as an emulsion or a dispersion. Means.

  The “aqueous solvent” in the present specification means water or a liquid containing water as a main component. Examples of solvents that can be used in combination with water as the main component include alcohols such as methanol, ethanol, isopropanol, and n-propanol; glycols such as ethylene glycol and diethylene glycol; ketones such as acetone and methyl ethyl ketone; And those that are not easily phase separated.

  Further, the “solvent solvent” referred to in the present specification means a solvent other than the above “aqueous solvent”, and a solvent not containing water can be treated as a “solvent solvent”. Examples of the “solvent solvent” include hydrocarbon solvents such as hexane and pentane, aromatic solvents such as xylene, toluene and benzene, ketone solvents such as methyl ethyl ketone and acetone, and alcohol solvents such as propanol, ethanol and methanol. Examples thereof include a solvent or a mixed solvent thereof.

  Regarding the superiority of the thermal transfer sheet 100 of the embodiment having the above-described features, the comparative thermal transfer sheet (1) in which both the intermediate layer and the metal ink layer contain a solvent-based resin, the intermediate layer, and the metal ink layer are both A comparative thermal transfer sheet (2) containing an aqueous resin will be described as an example. Note that the metal ink layers of the comparative thermal transfer sheets (1) and (2) contain metal powder.

  Production of a thermal transfer sheet provided with a metal ink layer is carried out by forming an intermediate layer on a substrate, and applying a metal ink layer coating liquid on the intermediate layer to form a metal ink layer. Since the metal ink layer of the thermal transfer sheet of one embodiment and the comparative thermal transfer sheet (1) contains a solvent-based resin and a metal powder, a solvent-based resin and a metal powder are used for forming the metal ink layer. And a coating liquid for a metal ink layer containing a solvent-based solvent for dissolving the solvent-based resin in the coating liquid (hereinafter, this metallic ink layer coating liquid is referred to as a “solvent-based coating liquid”). Say) is used. Since the metal ink layer of the comparative thermal transfer sheet (2) contains a water-based resin and metal powder, the formation of this metal ink layer is carried out with the water-based resin, metal powder, and water-based resin in the coating liquid. A metal ink layer coating solution containing an aqueous solvent for dissolving or dispersing (hereinafter, this metal ink layer coating solution is referred to as “aqueous coating solution”) is used.

  As described above, since the intermediate layer of the comparative thermal transfer sheet (1) contains a solvent-based resin, the above-mentioned “solvent-based coating” is formed on the intermediate layer in the production stage of the comparative thermal transfer sheet (1). When the metal ink layer is formed by coating the “working fluid”, the solvent-based resin contained in the intermediate layer is dissolved in the solvent-based solvent contained in the “solvent-based coating fluid”, and the intermediate The layer and the metal ink layer are mixed. As a result, a part of the metal powder that should be present in the metal ink layer originally moves to the intermediate layer side.

  Further, as described above, since the intermediate layer of the comparative thermal transfer sheet (2) contains an aqueous resin, the “aqueous coating” is formed on the intermediate layer in the production stage of the comparative thermal transfer sheet (2). When the metal ink layer is formed by applying the “working fluid”, the aqueous resin contained in the intermediate layer is dissolved or dispersed in the aqueous solvent contained in the “aqueous coating solution”. As a result, the intermediate layer and the metal ink layer are mixed. As a result, like the comparative heat transfer sheet (1), a part of the metal powder that should be present in the metal ink layer is transferred to the intermediate layer side.

  Then, by mixing the intermediate layer and the metal ink layer, in the comparative thermal transfer sheet (1), between the intermediate layer and the metal ink layer, the solvent resin of the intermediate layer and the solvent resin of the metal ink layer A mixed layer is formed, and metal powder is contained in the mixed layer. In the comparative thermal transfer sheet (2), a mixed layer in which the aqueous resin of the intermediate layer and the aqueous resin of the metal ink layer are mixed is formed between the intermediate layer and the metal ink layer. Metal powder will be included.

  On the other hand, in the thermal transfer sheet of one embodiment, the intermediate layer contains a water-based resin, and the above-mentioned “solvent-based coating liquid” is used for forming the metal ink layer. Therefore, in the thermal transfer sheet of one embodiment, when the metal ink layer is formed by applying the “solvent coating liquid” on the intermediate layer in the production stage, the intermediate layer and the metal ink layer are It is possible to suppress mixing and migration of the metal powder contained in the metal ink layer to the intermediate layer side. Further, a mixed layer is not formed between the intermediate layer and the metal ink layer as in the comparative thermal transfer sheet.

  Although the details are not clear, comparative thermal transfer sheets (1) and (2) in which a mixed layer is formed by mixing the intermediate layer and the metal ink layer, and further, the mixed layer contains metal powder. Compared with the thermal transfer sheet of one embodiment, the brightness of the printed material obtained by transferring the transfer layer onto the transfer material is low. That is, according to the thermal transfer sheet of one embodiment, by adopting “water-based resin” as the resin contained in the intermediate layer, and adopting “solvent resin” as the resin contained in the metal ink layer, It is possible to suppress the metal powder from moving to the intermediate layer side, and as a result, it is possible to obtain a thermal transfer sheet from which a printed matter with high luminance can be obtained. This is also clear from the results of Examples and Comparative Examples described later.

(Base material)
The base material 1 is an essential configuration in the thermal transfer sheet 100 of one embodiment, and the transfer layer 20 provided on one surface of the base material 1 or any arbitrary provided between the base material 1 and the transfer layer 20. It is provided in order to hold a layer (for example, an arbitrary release layer described later) and a back layer optionally provided on the other surface of the substrate 1. The material of the substrate 1 is not particularly limited, but it is desirable that the transfer layer 20 has a mechanical characteristic that can withstand heat applied when the transfer layer 20 is transferred onto a transfer target and has no trouble in handling. Examples of such a substrate 1 include polyesters such as polyethylene terephthalate, polycarbonate, polyimide, polyetherimide, cellulose derivatives, polyethylene, polypropylene, polystyrene, acrylic, polyvinyl chloride, polyvinylidene chloride, nylon, polyether ether ketone, and the like. Various plastic films or sheets can be mentioned. Moreover, the thickness of the base material 1 can be appropriately set according to the material so that the strength and heat resistance are appropriate, and the range of 2.5 μm to 100 μm is common.

(Transfer layer)
The transfer layer 20 is provided so as to be peelable from the substrate 1, and is a layer that is peeled off from the substrate and transferred onto the transfer target during thermal transfer. In the present invention, the transfer layer 20 includes the intermediate layer 5 and the metal ink layer 7 as essential layers. As shown in FIGS. 1 and 2, the transfer layer 20 includes the intermediate layer 5, A laminated structure in which the metal ink layers 7 are laminated in this order is adopted. Hereinafter, the intermediate layer 5 and the metal ink layer 7 will be described.

<Intermediate layer>
The intermediate layer 5 constituting the transfer layer 20 is provided so as to be peelable from the substrate 1 and is a layer that is transferred onto the transfer medium together with the metal ink layer 7 during thermal transfer. The intermediate layer 5 is a layer that is in direct contact with the metal ink layer 7.

  The intermediate layer 5 may have a single-layer configuration composed of one layer as shown in FIG. 1, or a laminated configuration composed of two or more layers as shown in FIG. It may be. For example, in the form shown in FIG. 2, the intermediate layer 5 has a laminated structure in which the peeling layer 3 and the barrier layer 4 are laminated in this order from the substrate 1 side. The barrier layer 4 is a metal ink layer. 7 is in direct contact. In addition, when an intermediate | middle layer exhibits laminated | stacked structure, the layer (barrier layer 4 in the form shown in FIG. 2) which contact | connects a metal ink layer directly among the layers which comprise the intermediate | middle layer 5 contains aqueous resin. ing

  The aqueous resin contained in the intermediate layer 5 may be any resin that satisfies the condition that it is a resin that can be dissolved or dispersed in an aqueous solvent, and examples thereof include water-soluble resins and water-dispersible resins. . Water-soluble resins include polyvinyl pyrrolidone, polyvinyl alcohol, hydroethyl cellulose, carboxymethyl cellulose, phenol resin, polyacrylic acid, polyacrylate ester, polyacrylate ester copolymer, water-soluble acrylic resin such as polymethacrylic acid, gelatin , Starch, casein, and modified products thereof.

  Examples of the water-dispersible resin include resins that exist in an emulsion state or a dispersion state in the coating liquid. Such resins include vinyl chloride resin emulsions, vinyl chloride-vinyl acetate resin emulsions, vinyl chloride resin emulsions such as vinyl chloride-acrylic resin emulsions, acrylic resin emulsions, urethane resin emulsions, PVC resin dispersions, acrylic resins. -Based resin dispersion, urethane-based resin dispersion, and the like. Examples of urethane resin emulsions and urethane resin dispersions include ester urethane resin emulsions, ether urethane resin emulsions, ester / ether urethane resin emulsions, carbonate urethane resin emulsions, and dispersions of these urethane resins. John and the like can be mentioned. In this specification, the emulsion state means that the emulsifier molecule forms a micelle by coordinating the hydrophobic group on the resin side and the hydrophilic group on the coating liquid side around one resin. The state that exists inside. Further, the dispersion state means a state in which a single resin is stably dispersed in the coating liquid by the action of hydrophilic groups present on the surface thereof.

  Among these water-based resins, water-soluble resins such as polyvinyl alcohol and polyvinyl pyrrolidone, water-dispersible resin acrylic resin emulsion, acrylic resin dispersion, ether urethane resin emulsion, and ether urethane resin dispersion are: A water-based resin having good solvent resistance. By using the intermediate layer 5 containing these water-based resins, a printed material obtained by transferring the transfer layer 20 including the intermediate layer 5 onto a transfer target is obtained. Chemical durability can be improved. Furthermore, according to the intermediate layer 5 containing these water-based resins, it is possible to further improve the gloss of the printed matter obtained by transferring the transfer layer 20 including the intermediate layer 5 onto the transfer target. .

  The mid layer 5 may contain one kind alone as a water-based resin, or two or more kinds may be used in combination.

  As described above, the intermediate layer 5 may have a single-layer configuration or a stacked configuration, but the thermal transfer sheet 100 according to one embodiment allows the intermediate layer 5 to be peeled from the substrate 1. It is an essential condition that it is provided. Therefore, one form of the intermediate layer 5 in the case of a single layer structure functions as a layer that can be peeled off from the substrate 1. In addition, this does not require that the intermediate layer 5 itself having a single layer structure has a function of peeling from the base material. For example, between the base material 1 and the intermediate layer 5, By providing a release layer (not shown), the intermediate layer 5 can be provided with peelability from the substrate 1.

  In the case of providing the peelable function from the base material 1 to the intermediate layer 5 itself having a single layer structure without providing any release layer or the like, the base material 1 is selected from the aqueous resins exemplified above. What is necessary is just to select resin which has peelability from. For example, polyvinyl alcohol, acrylic resin emulsion, and the like can be used as an aqueous resin having peelability from the substrate 1. In addition, although the intermediate layer 5 of the thermal transfer sheet of one embodiment is required to contain an aqueous resin, generally, the peelability of the layer containing the aqueous resin contains a solvent-based resin. It tends to be lower than the peelability of the layer. Therefore, when the intermediate layer 5 itself is provided with a function of peelability from the base material 1 without providing any release layer, the intermediate layer 5 is formed from the base material 1 side as shown in FIG. A layer for imparting peelability (release layer 3 shown in FIG. 2) and a layer for preventing the intermediate layer 5 and the metal ink layer 7 from mixing (barrier layer 4 shown in FIG. 2). The laminated intermediate layer 5 is preferably used. According to the intermediate layer 5 of the form shown in FIG. 2, the intermediate layer 5 that can suppress mixing with the metal ink layer 7 while having releasability by appropriately selecting the resin of the release layer 3. can do. Hereinafter, the intermediate layer 5 will be described focusing on an example in which the peeling layer 3 and the barrier layer 4 are laminated in this order from the substrate 1 side.

"Peeling layer"
The release layer 3 constituting the intermediate layer 5 may be any resin that has peelability from the substrate 1. Examples of the resin having peelability include acrylic resin, phenoxy resin, polycarbonate resin, polystyrene resin, and silicone-modified resin. These components may be used alone or in combination of two or more.

  In the thermal transfer sheet having the form shown in FIG. 2, when the transfer layer 20 is transferred onto a transfer target to form a print product, the release layer 3 is a layer positioned on the outermost surface of the print product. Accordingly, the release layer 3 may contain a lubricant for the purpose of improving the scratch resistance of the printed material. Examples of the lubricant include silicones such as modified silicone oil and silicone-modified resin, metal soaps such as zinc stearate, zinc stearyl phosphate, calcium stearate, magnesium stearate, fatty acid amide, polyethylene wax, carnauba wax, paraffin wax. , Etc. In addition to the lubricant, the release layer 3 is coated with a methacrylate ester copolymer, a vinyl chloride / vinyl acetate copolymer, a polyester resin, a polycarbonate resin, an acrylic resin, an ultraviolet absorbing resin, an epoxy resin, a polystyrene resin, and a polyurethane resin. An acrylic urethane resin, a resin obtained by modifying each of these resins with silicone, a mixture of these resins, an ionizing radiation curable resin, an ultraviolet absorbing resin, or the like may be contained.

  As the ultraviolet absorbing resin, for example, a resin obtained by reacting and bonding a reactive ultraviolet absorbent to a thermoplastic resin or the above ionizing radiation 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 optional components exemplified above, the release layer 3 includes, for example, a light stabilizer such as a hindered amine or Ni chelate, an antioxidant such as a hindered phenol, sulfur, phosphorus or lactone. Etc. may be contained. One of these optional components may be used alone, or two or more thereof may be used in combination.

  As a method for forming the release layer 3, a release layer coating solution prepared by dissolving or dispersing the components exemplified above in an appropriate solvent-based solvent is prepared. Alternatively, on an arbitrary layer provided between the substrate 1 and the intermediate layer 5, it is formed by applying and drying using a known means such as a gravure printing method, a screen printing method, or a reverse roll coating method using a gravure plate. can do. The thickness of the release layer 3 is generally in the range of 0.1 to 5 μm, and preferably in the range of 0.5 to 5 μm.

"Barrier layer"
The barrier layer 4 constituting the intermediate layer 5 is a layer having a function of suppressing mixing with the metal ink layer 7 containing a solvent-based resin, and contains a water-based resin. As the water-based resin, those described above can be appropriately selected and used, and description thereof is omitted here.

  The barrier layer 4 may contain a filler together with the aqueous resin. By adding a filler to the barrier layer 4 constituting the intermediate layer 5, the shearing property of the barrier layer 4 can be improved, and the transfer layer 20 including the intermediate layer 5 is placed on the transfer target by improving the shearing property. It is possible to improve the foil breakability of the transfer layer 20 when transferring to the sheet.

  Examples of the filler include organic fillers, inorganic fillers, and organic-inorganic hybrid fillers. These fillers may be powder or sol-based. Examples of the organic filler in the powder include acrylic particles such as non-crosslinked acrylic particles and crosslinked acrylic particles, polyamide particles, fluorine particles, and polyethylene wax. Examples of the powdery inorganic filler include metal oxide particles such as calcium carbonate particles, silica particles, and titanium oxide. Examples of the organic-inorganic hybrid filler include those obtained by hybridizing silica particles to an acrylic resin. Examples of the sol-based filler include silica sol-based, alumina sol-based, and organosol-based fillers. These fillers may be used alone or in combination of two or more. Although there is no limitation in particular about content of a filler, it is preferable that it is 85 mass% or less with respect to the solid content total amount of the barrier layer 4. FIG.

  Although there is no limitation in particular about the particle diameter of a filler, it is preferable that it is a 3 micrometer or less filler. By making the barrier layer 4 contain a filler having a particle size of 3 μm or less, the foil breakability can be further improved. In addition, the particle diameter of a filler means a volume average particle diameter. The particle size of the filler can be measured, for example, by analyzing the BET method or the electron microscope observation result with image analysis type particle size distribution measurement software. The same applies to the particle size of the metal powder described later.

  Further, instead of containing the filler in the barrier layer 4 or containing the filler in the barrier layer 4, the release layer 3 described above may contain a filler.

  As a method for forming the barrier layer 4, a barrier layer coating solution is prepared by dissolving or dispersing the above-described aqueous resin and various components added as necessary in an appropriate aqueous solvent. The coating liquid for coating is applied to the release layer 3 or an arbitrary layer provided on the release layer 3 using a known means such as a gravure printing method, a screen printing method, a reverse roll coating method using a gravure plate, It can be formed by drying. The thickness of the barrier layer 4 is preferably in the range of 0.01 μm to 5 μm, and more preferably in the range of 0.02 μm to 3 μm.

  As described above, the intermediate layer 5 having the laminated structure in which the release layer 3 and the barrier layer 4 are laminated has been described as the intermediate layer 5. However, when the intermediate layer 5 has a single layer structure, the barrier described above is used. The layer 4 may be used as the intermediate layer 5 as it is. In this case, as described above, in order to satisfy the peelability of the intermediate layer 5 from the base material 1, the intermediate layer 5 containing a water-based resin having peelability is used, or the base material 1 and the intermediate layer 5. A release layer may be provided between the two.

  An arbitrary layer can be provided between the release layer 3 and the barrier layer 4. For example, a plasticizer-resistant layer for improving the plasticizer resistance of the printed material to which the transfer layer 20 has been transferred may be provided.

<Metal ink layer>
The metal ink layer 7 is a layer that is transferred onto the transfer medium together with the intermediate layer 5 at the time of thermal transfer, and imparts a metallic gloss to the printed matter obtained by transferring the transfer layer 20 onto the transfer medium. It is a layer to do. The metal ink layer 7 contains metal powder and a solvent-based resin as essential components.

  The solvent-based resin means a resin that dissolves in the solvent-based solvent. Examples of the solvent-based resin include, for example, vinyl chloride resin, vinylidene chloride resin, vinyl acetate resin, acrylic resin, olefin resin, polyester resin, polyurethane resin, and copolymers thereof.

  In the illustrated embodiment, the metal ink layer 7 is located on the outermost surface of the thermal transfer sheet, and when the transfer layer 20 is transferred onto the transfer target, the transfer target and the metal ink layer 7 are in direct contact with each other. Become. Therefore, in this embodiment, it is desirable that the metal ink layer 7 has adhesiveness with the transfer target. Since the solvent-based resin exemplified above is a resin having relatively high adhesiveness, it is possible to sufficiently satisfy the adhesiveness to the transfer object by using these solvent-based resins. In addition, when taking the measure which satisfies the adhesiveness with the transfer layer 20 on the transfer target side, the metal ink layer 7 itself may not have the adhesiveness. In addition, an adhesive layer (not shown) may be provided on the metal ink layer 7. In this case, the adhesive layer contains a water-based resin in order to suppress mixing of the adhesive layer and the metal ink layer. It is preferable.

  Examples of the metal powder include gold, silver, copper, aluminum, magnesium, and alloys thereof. Among these metal powders, aluminum powder is preferable in consideration of the brightness and cost of the printed matter obtained by transferring the transfer layer 20 onto the transfer target.

  The metal powder particles are preferably scaly or foil-like, and preferably have a thickness of 0.001 to 3 μm and an average diameter of 0.1 to 100 μm.

  The content of the metal powder is preferably 20 parts by mass or more with respect to 100 parts by mass of the solvent-based resin contained in the metal ink layer 7. By setting the content of the metal powder in a preferable range, it is possible to further improve the luminance of the printed matter obtained by transferring the transfer layer 20 including the metal ink layer 7 onto the transfer target. . Although there is no limitation in particular about the upper limit of content, when the adhesiveness of the metal ink layer 7 and a to-be-transferred body etc. are considered, it is preferable that it is 500 mass parts or less.

  In addition, this does not limit the particle diameter of metal powder which the metal ink layer 7 contains, or content. For example, when the same metal powder is used as the metal powder contained in the metal ink layer of the thermal transfer sheet of the embodiment and the comparative thermal transfer sheet (1), and the content of the metal powder is the same The printed matter obtained using the thermal transfer sheet of one embodiment is less than the comparative thermal transfer sheet (1) because the intermediate layer 5 and the metal ink layer 7 are prevented from being mixed. The brightness is high.

  Further, a colorant such as a dye or a pigment can be contained in the metal ink layer 7 to change the hue of the metal ink layer 7. By changing the hue of the metal ink layer 7, the decorativeness can be further improved. As the colorant, for example, those having various hues such as yellow, red, green, and blue can be selected. By selecting a colorant having these hues, the metal ink layer 7 can be made of gold, copper, It can easily give the hue and gloss of a metal such as bronze.

  Although there is no limitation in particular about the formation method of the metal ink layer 7, For example, the solvent type resin demonstrated above is melt | dissolved in a suitable solvent type | system | group solvent, a metal powder, and various components added as needed to this. The coating liquid for the metal ink layer to which is added is formed by applying and drying on the intermediate layer 5 using a known means such as a gravure printing method, a screen printing method, a reverse roll coating method using a gravure plate, and the like. Can do. Although there is no limitation in particular about the thickness of the metal ink layer 7, It is preferable that it is the range of 0.1 micrometer or more and 3 micrometers or less.

(Release layer)
A release layer (not shown) may be provided between the substrate 1 and the intermediate layer 5. For example, when the intermediate layer 5 having a single layer structure is provided on the base material 1 and the intermediate layer 5 itself does not have peelability from the base material 1, a release layer is provided, and the intermediate layer 5 is provided. Can be peeled from the substrate 1. The release layer is an arbitrary layer in the thermal transfer sheet 100 of one embodiment.

  Examples of the resin constituting the release layer include waxes, silicone wax, silicone resin, silicone-modified resin, fluorine resin, fluorine-modified resin, polyvinyl alcohol, acrylic resin, heat-crosslinkable epoxy-amino resin, and heat-crosslinkable alkyd. -An amino resin etc. can be mentioned. These resins may be used alone or in combination of two or more. Although there is no limitation in particular about the thickness of a mold release layer, about 0.5 micrometer or more and about 5 micrometers or less are common.

  In the form shown in FIG. 2, a release layer may be provided between the substrate 1 and the intermediate layer 5, in other words, between the substrate 1 and the release layer 3.

(Back layer)
Further, a back layer (not shown) may be provided on a surface different from the surface on which the transfer layer 20 of the substrate 1 is provided to improve heat resistance and running performance of the thermal head during printing. Good. In addition, a back surface layer is arbitrary structures in the thermal transfer sheet 100 of one Embodiment.

  The back layer 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.

  In addition to the above thermoplastic resin, the back layer has a wax, a higher fatty acid amide, a phosphoric ester compound, a metal soap, a silicone oil, a surfactant release agent, etc., a fluororesin for the purpose of improving slip properties. It is preferable that various additives such as organic particles such as silica, clay, talc, and calcium carbonate are contained, and it is particularly preferable that at least one of phosphoric acid ester or metal soap is contained. .

  The back layer is formed, for example, on the base material 1 by applying a coating liquid in which the thermoplastic resin and various additives added as necessary are dispersed or dissolved in an appropriate solvent, a gravure printing method, a screen printing method, It can be formed by coating and drying by known means such as reverse roll coating printing using a gravure plate. The thickness of the back layer is preferably in the range of 0.1 μm to 5 μm, more preferably in the range of 0.3 μm to 2 μm, from the viewpoint of improving heat resistance and the like.

<< Thermal transfer sheet of other embodiment >>
Next, a thermal transfer sheet 100 according to another embodiment of the present invention (hereinafter referred to as a thermal transfer sheet according to another embodiment) will be described.

  In the thermal transfer sheet of another embodiment, a transfer layer 20 is provided on one surface of the substrate 1 so as to be peelable from the substrate 1, and the transfer layer 20 includes the intermediate layer 5 and the intermediate layer. 5 has a laminated structure in which a metal ink layer 7 in direct contact with 5 is laminated.

  In the thermal transfer sheet 100 according to one embodiment, the metal ink layer 7 contains metal powder and an aqueous resin, and the intermediate layer 5 that is in direct contact with the metal ink layer 7 contains a solvent-based resin. It is characterized by containing. That is, in the thermal transfer sheet of one embodiment, the metal ink layer 7 contains a solvent-based resin, whereas in the thermal transfer sheet of another embodiment, the metal ink layer 7 contains a water-based resin. In the thermal transfer sheet of one embodiment, the intermediate layer 5 contains a water-based resin, whereas in the thermal transfer sheet of another embodiment, the intermediate layer 5 contains a solvent-based resin. The sheet is different. Other than this difference, the thermal transfer sheet of the other embodiment is common to the thermal transfer sheet of the embodiment, and in the intermediate layer 5 of the thermal transfer sheet of the embodiment, the description that is a water-based resin, In the metal ink layer 7 of one embodiment, the description with the aqueous solvent may be replaced with the aqueous solvent, and the description with the solvent-based resin may be replaced with the aqueous resin, and the description with the solvent-based solvent may be replaced with the aqueous solvent. .

  In the thermal transfer sheet of the other embodiment, the intermediate layer 5 and the metal ink layer 7 can be prevented from being mixed for the same reason as the thermal transfer sheet of the above-described embodiment, as compared with the conventional thermal transfer sheet. A printed matter with high brightness can be obtained.

  As described above, the thermal transfer sheet 100 of the present invention has been described by taking the thermal transfer sheet of one embodiment and other embodiments as an example, but may take various forms within the scope of the present invention. it can. For example, a dye layer-integrated thermal transfer sheet (not shown) in which a dye layer is provided in the same order as the surface on which the transfer layer 20 of the substrate 1 is provided may be used. The dye layer may be a single dye layer. For example, a yellow dye layer, a magenta dye layer, and a cyan dye layer may be provided in this order in a plane order.

  Moreover, it is good also as a thermal transfer sheet which provided the receiving layer (not shown) on the metal ink layer 7. FIG. In the case where the receiving layer is provided on the metal ink layer 7, when the metal ink layer 7 contains a water-based resin, the receiving layer preferably contains a solvent-based resin. In the case where the layer 7 contains a solvent-based resin, the receiving layer preferably contains a water-based resin. By setting it as such a structure, it can suppress that a receiving layer and the metal ink layer 7 mix, and a printed matter with high brightness | luminance can be obtained. As the receiving layer, a conventionally known receiving layer may be appropriately selected in the fields of a thermal transfer image receiving sheet and an intermediate transfer medium.

  Next, the present invention will be described more specifically with reference to examples and comparative examples. Hereinafter, unless otherwise specified, parts or% is based on mass. Moreover, about the component which has solid content ratio, the value of the mass converted into solid content is shown.

Example 1
Using a polyethylene terephthalate film having a thickness of 5 μm as a base material, a release layer is formed on one surface by applying a release layer coating liquid having the following composition to 1.2 g / m ^{2 in} a dry state. did. Next, a barrier layer coating solution 1 having the following composition was applied on the release layer so as to be 0.2 g / m ² in a dry state to form a barrier layer. Next, a metal ink layer coating liquid having the following composition was applied on the barrier layer so as to be 0.5 g / m ² in a dry state to form a metal ink layer. Further, the back surface layer coating liquid having the following composition is applied to the other surface of the base material so as to be 1.0 g / m ² in a dry state, thereby forming the back surface layer, and the thermal transfer sheet of Example 1 Got.

<Coating liquid for release layer>
・ Acrylic resin 27 parts (Dianar BR-87 Mitsubishi Rayon Co., Ltd.)
・ 3 parts of vinyl chloride-vinyl acetate copolymer resin (Solvine CNL Nissin Chemical Industry Co., Ltd.)
・ Methyl ethyl ketone 35 parts ・ Toluene 35 parts

<Coating liquid 1 for barrier layer>
・ Polyvinyl alcohol resin (as water-soluble resin) 5 parts (Kuraray Poval PVA105 Kuraray Co., Ltd.)
・ Water 47.5 parts ・ Isopropyl alcohol 47.5 parts

<Coating liquid for metal ink layer>
・ 20 parts of aluminum powder (Aluminum paste 0670TS Toyo Aluminum Co., Ltd.)
・ Acrylic resin (as solvent-based resin) 10 parts (Dianar BR-83 Mitsubishi Rayon Co., Ltd.)
・ 10 parts of vinyl chloride-vinyl acetate copolymer resin (Solvine CNL Nissin Chemical Industry Co., Ltd.)
・ Methyl ethyl ketone 20 parts ・ Toluene 40 parts

<Back layer coating liquid>
-Polyvinyl acetal resin 60.8 parts (S-REC KS-1 Sekisui Chemical Co., Ltd.)
・ Polyisocyanate 4.2 parts (Bernock D750 Dainippon Ink & Chemicals, Inc.)
-Zinc stearyl phosphate 10 parts (LBT-1830 purification Sakai Chemical Industry Co., Ltd.)
・ Zinc stearate 10 parts (SZ-PF Sakai Chemical Industry Co., Ltd.)
・ 3 parts of polyethylene wax (Polywax 3000 Toyo Petrolite Co., Ltd.)
・ Methyl ethyl ketone 200 parts ・ Toluene 100 parts

(Example 2)
A thermal transfer sheet of Example 2 was obtained in the same manner as Example 1 except that the barrier layer coating solution 1 was changed to the barrier layer coating solution 2 having the following composition.

<Barrier layer coating solution 2>
-Polyvinylpyrrolidone resin (as water-soluble resin) 5 parts (PVP K-60 ISP Japan Co., Ltd.)
・ Water 47.5 parts ・ Isopropyl alcohol 47.5 parts

(Example 3)
A thermal transfer sheet of Example 3 was obtained in the same manner as in Example 1 except that the barrier layer coating solution 1 was changed to the barrier layer coating solution 3 having the following composition.

<Barrier layer coating solution 3>
・ Ether urethane resin (as water-dispersed resin) 5 parts (Superflex 130 Daiichi Kogyo Seiyaku Co., Ltd.)
・ Water 47.5 parts ・ Isopropyl alcohol 47.5 parts

Example 4
A thermal transfer sheet of Example 4 was obtained in the same manner as in Example 1 except that the barrier layer coating liquid 1 was changed to the barrier layer coating liquid 4 having the following composition.

<Barrier layer coating solution 4>
・ Water-based acrylic resin (as water-dispersed resin) 5 parts (Barrier Star B4100 Mitsui Chemicals)
・ Water 47.5 parts ・ Isopropyl alcohol 47.5 parts

(Example 5)
A thermal transfer sheet of Example 5 was obtained in the same manner as Example 1 except that the barrier layer coating solution 1 was changed to the barrier layer coating solution 5 having the following composition.

<Barrier layer coating solution 5>
-Polyvinylpyrrolidone resin (as water-soluble resin) 3.5 parts (PVP K-60 ISP Japan Co., Ltd.)
Alumina sol (as filler) 1.5 parts (alumina sol 200, manufactured by Nissan Chemical Industries, solid content 10.5%)
・ Water 47.5 parts ・ Isopropyl alcohol 47.5 parts

(Example 6)
A thermal transfer sheet of Example 6 was obtained in the same manner as Example 1 except that the barrier layer coating liquid 1 was changed to the barrier layer coating liquid 6 having the following composition.

<Barrier layer coating solution 6>
・ Carbonic urethane resin (as water dispersion resin) 5 parts (Superflex 460 Daiichi Kogyo Seiyaku Co., Ltd.)
・ Water 47.5 parts ・ Isopropyl alcohol 47.5 parts

(Example 7)
A thermal transfer sheet of Example 7 was obtained in the same manner as Example 1 except that no release layer was formed.

(Comparative Example 1)
A thermal transfer sheet of Comparative Example 1 was obtained in the same manner as in Example 1 except that the barrier layer coating solution 1 was changed to the barrier layer coating solution A having the following composition.

<Barrier layer coating liquid A>
・ Polyester resin (as solvent-based resin) 5 parts (Byron 220 Toyobo Co., Ltd.)
・ Methyl ethyl ketone 47.5 parts ・ Toluene 47.5 parts

(Comparative Example 2)
A thermal transfer sheet of Comparative Example 2 was obtained in the same manner as in Example 1 except that the barrier layer coating solution 1 was changed to the barrier layer coating solution B having the following composition.

<Coating solution B for barrier layer>
・ Acrylic resin (as solvent-based resin) 5 parts (BR-83 Mitsubishi Rayon Co., Ltd.)
・ Methyl ethyl ketone 47.5 parts ・ Toluene 47.5 parts

(Comparative Example 3)
A thermal transfer sheet of Comparative Example 3 was obtained in the same manner as in Example 1 except that the barrier layer coating solution 1 was not applied.

(Formation of prints)
Cut out the protective layer part of the genuine ribbon of the sublimation type transfer printer (DS-40 manufactured by DNP Photo Lucio Co., Ltd.), cut and affix the thermal transfer sheets of the Examples and Comparative Examples obtained above to the part. By printing a solid white image (with transfer of the cut and pasted protective layer) on 40 genuine image receiving paper, the transfer layer (peeling layer / barrier layer / metal ink layer) is transferred to the image receiving paper. A print of a comparative example was obtained.

(Glossiness evaluation)
The glossiness of each of the Examples and Comparative Examples obtained by forming the above-mentioned prints was measured at a measurement angle of 45 ° using Gloss Meter VG7000 (manufactured by Nippon Denshoku Co., Ltd.). Glossiness was evaluated based on the following evaluation criteria based on the glossiness. The evaluation results are shown in Table 1.

<Evaluation criteria>
A: The measurement result of glossiness is a reference value +100 or more.
○: The measurement result of glossiness is the reference value +50 or more and less than 100.
X: The measurement result of glossiness is less than the reference value +50.

(Solvent resistance evaluation)
In order to evaluate the solvent resistance of the barrier layer located on the outermost surface of the printed matter, each barrier layer coating solution used for forming the thermal transfer sheet of each example is used, and this coating solution is dried. The solid state when 1 g of the resulting solid matter was immersed in a methyl ethyl ketone / toluene mixed solution for 24 hours was visually observed, and the solvent resistance was evaluated based on the following evaluation criteria. The evaluation results are also shown in Table 1. In addition, solvent resistance evaluation was performed only about the thermal transfer sheet of the Example.

<Evaluation criteria>
○: The solid content did not dissolve.
X: The solid content was dissolved.

DESCRIPTION OF SYMBOLS 1 ... Base material 3 ... Release layer 4 ... Barrier layer 5 ... Intermediate layer 7 ... Metal ink layer 20 ... Transfer layer 100 ... Thermal transfer sheet

Claims (5)

A thermal transfer sheet having a base material and a transfer layer provided to be peelable from the base material,
The transfer layer has a laminated structure in which an intermediate layer and a metal ink layer in direct contact with the intermediate layer are laminated,
The metal ink layer contains metal powder and a solvent-based resin,
The thermal transfer sheet, wherein the intermediate layer contains an aqueous resin. The intermediate layer has a laminated structure in which a release layer and a barrier layer are laminated in this order,
The barrier layer is in direct contact with the metal ink layer;
The thermal transfer sheet according to claim 1, wherein the barrier layer contains an aqueous resin.   The thermal transfer sheet according to claim 1 or 2, wherein the water-based resin is any one of a water-soluble resin, an emulsion resin, and a dispersion resin. A thermal transfer sheet having a base material and a transfer layer provided to be peelable from the base material,
The transfer layer has a laminated structure in which an intermediate layer and a metal ink layer in direct contact with the intermediate layer are laminated,
The metal ink layer contains metal powder and an aqueous resin,
The thermal transfer sheet, wherein the intermediate layer contains a solvent-based resin. The intermediate layer has a laminated structure in which a release layer and a barrier layer are laminated in this order,
The barrier layer is in direct contact with the metal ink layer;
The thermal transfer sheet according to claim 4, wherein the barrier layer contains a solvent-based resin.

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