JP2009083166A - Thermal transfer sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal transfer sheet which ensures high metal glossiness of a printed product, and concealability to a base while having a thin metal layer and is suitable for overlap transfer in a plurality of colors. <P>SOLUTION: The thermal transfer sheet is provided with a transfer layer including at least a peeling layer, a metal thin film layer containing leafing type aluminum powder and a binder and a black adhesive layer containing a black coloring agent as the outer most layer in this order on one surface of a film base material, wherein the transmission density is 0.7-2.0. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a thermal transfer sheet for printing characters, designs and the like having a metallic feeling such as metallic luster on a transfer material by a thermal transfer recording method.

  As a method for obtaining a printed matter having a metallic luster, a method using a thermal transfer recording system using a thermal head and a thermal transfer sheet is known. For example, Patent Document 1 discloses a thermal transfer sheet for obtaining a printed matter having a metallic luster, in which a release layer, a metal vapor deposition layer, and an adhesive layer are sequentially laminated on one surface of a base film. When a metal vapor deposition layer is provided on a base material such as the above-mentioned Patent Document 1, it is necessary to process the metal vapor deposition layer by a special method such as a vacuum vapor deposition method or a sputtering method, Since the deposited layer is inferior in flexibility, there is a problem that cracks are likely to occur upon impact or outdoor exposure. As a countermeasure against such a problem, Patent Document 2 discloses a thermal transfer sheet characterized in that a metallic layer containing at least a leafing type aluminum powder is provided on one surface of a base film. Yes.

JP-A-8-142530 JP 2002-103824 A

  In the case of the thermal transfer sheet of the melt transfer system, the adhesive layer side is opposed to the transfer target, and the substrate is heated by a thermal transfer printer having a heating device such as a thermal head from the base film side, as shown in FIG. Only in the heating unit 70, the transfer layer 50 including the release layer 10, the metal layer 20, and the adhesive layer 30 is transferred to the transfer target 60. Since this transfer layer has a thickness, a step is generated as shown in FIG. If the level difference is too large, as shown in FIG. 4, when the second color transfer layer 52 is overlaid on the first color transfer layer 51, a gap 80 due to the level difference is generated, and a portion 81 that is not transferred to the boundary may be generated. In order to prevent such a problem, it is desirable to make the transfer layer as thin as possible. In the case of a thermal transfer sheet for obtaining a printed matter having a metallic luster, the metal layer is usually the thickest layer in the transfer layer, and therefore it is desired to make the metal layer thinner. Moreover, since the material which forms a metal layer is generally expensive, it is desirable that the metal layer is thin. However, when the metal layer is made thin, there is a problem that the metallic luster of the printed material becomes insufficient or the concealability of the printed material with respect to the background becomes low.

  Accordingly, in order to solve the above-described problems, the present invention provides a thermal transfer sheet that has a thin metallic layer and has a high metallic luster and a high concealment property for a printed material, and is suitable for multi-color overlay transfer. With the goal.

  In order to solve the above problems, the present invention contains at least one release layer, a metal thin film layer containing a leafing aluminum powder and a binder resin, and a black colorant as an outermost layer on one surface of a film substrate. Provided is a thermal transfer sheet provided with a transfer layer containing a black adhesive layer in this order and having a transmission density of 0.7 to 2.0.

  According to the present invention, the metallic luster is obtained by using the metal thin film layer containing the leafing type aluminum powder and the binder resin, and the black adhesive layer adjusted so that the transmission density of the thermal transfer sheet is 0.7 to 2.0. By realizing the feeling, it is possible to obtain a thermal transfer sheet that has a thin metallic layer and has a high metallic luster and a high concealment property for the background, and is suitable for multi-color overlay transfer.

  In the thermal transfer sheet of the present invention, the total thickness of the transfer layer is preferably 1 μm to 2 μm from the viewpoint of being suitable for multiple color transfer.

  In the thermal transfer sheet of the present invention, the black adhesive layer was adjusted so that the black colorant contained 5% to 20% by weight of the black colorant so that the transmission density of the thermal transfer sheet was 0.7 to 2.0. It is preferable from the viewpoint that a black adhesive layer can be easily obtained.

In the thermal transfer sheet of the present invention, the black adhesive layer is provided at a solid content of 0.4 g / m ^{2 to} 0.8 g / m ² , and the thermal transfer sheet has a transmission density of 0.7 to ² . This is preferable because a black adhesive layer adjusted to be 0 can be easily obtained.

  In the thermal transfer sheet of the present invention, the leafing-type aluminum powder is produced by forming an aluminum film by vapor deposition on a carrier sheet provided with a release layer, peeling the aluminum film from the carrier sheet, and subdividing it. Among them, the aluminum powder is preferable because the metallic gloss of the printed material is excellent.

  In the thermal transfer sheet of the present invention, a heat-resistant slipping layer is further provided on the other surface of the film substrate where the transfer layer is not provided. This is preferable from the viewpoint of improving the slipperiness of the resin and preventing sticking.

The thermal transfer sheet of the present invention has a thin metal layer, and has a high metallic luster and a high concealment property for the background, and has an effect that it is suitable for multiple color transfer.
In addition, the thermal transfer sheet of the present invention realizes a metallic luster with a metal thin film layer containing a leafing type aluminum powder and a binder resin and a black adhesive layer, so it has excellent flexibility and cracks in the metal layer upon impact or outdoor exposure. Can be produced inexpensively and easily.
Moreover, unlike the case of the conventional metal vapor deposition layer, the thermal transfer sheet of this invention can also make the thickness of a base film thin, and can make the resolution of a printing high.

The thermal transfer sheet according to the present invention has at least one release layer, a metal thin film layer containing leafing type aluminum powder and a binder resin, and a black adhesive layer containing a black colorant as the outermost layer on one surface of the film substrate. A transfer layer including this order is provided, and the transmission density is 0.7 to 2.0.
Here, the transmission density of the thermal transfer sheet is measured using a transmission density measuring device (Macbeth TR924, manufactured by Macbeth Co.) according to JIS K 7653-1988.

In the thermal transfer sheet of the present invention, as a thin metal layer, a black adhesion adjusted so that the transmission density of the thermal transfer sheet is 0.7 to 2.0 on a metal thin film layer containing leafing type aluminum powder and a binder resin. By using the layers in combination, it is possible to achieve excellent metallic luster of the printed material and concealment with respect to the base, even though the metal layer is thin.
The metal layer containing the leafing type aluminum powder and the binder resin is excellent in flexibility, and has an advantage that it can be easily manufactured without causing a problem that the metal layer is cracked by impact or outdoor exposure. However, when the metal layer containing the leafing type aluminum powder and the binder resin is made into a thin film, there is a problem that the metallic luster of the printed material becomes insufficient or the background of the printed material is seen through. On the other hand, in the present invention, in the printed material after the thermal transfer, the adhesive layer located on the surface of the transfer material and below the metal thin film layer is a black layer adjusted to have a predetermined transmission density, By doing so, the concealability with respect to the transfer object becomes sufficient, and the metallic luster feeling due to the thin metal layer can be sufficiently felt. Even if the black layer is separately provided between the metal thin film layer and the adhesive layer, the metallic luster feeling and concealment are improved, but above all, the adhesive layer necessary for fixing the metal thin film layer on the transfer target is described above. By using a black layer, the process can be omitted, which contributes to the thinning of the transfer layer.
Since the thermal transfer sheet of the present invention uses a thin metal thin film layer, the thickness of the transfer layer as a print is also reduced. Therefore, the thermal transfer sheet of the present invention is suitable for overlap transfer because it is difficult to cause a step in the transfer layer even when multiple colors are transferred and the transfer portion does not transfer to the boundary portion. .

  Moreover, since the thermal transfer sheet of the present invention is provided by coating by using a metal thin film layer containing a leafing type aluminum powder and a binder resin, unlike the conventional metal vapor deposition layer, the thickness of the base film is reduced. It is possible to increase the printing resolution. Furthermore, since the metal thin film layer containing the leafing type aluminum powder and the binder resin is provided by coating, the metal thin film layer can be formed into a desired pattern, so that the other dye layer and the metal thin film layer are arranged in the order of heat transfer. A sheet can be easily produced.

FIG. 1 is one embodiment of the thermal transfer sheet of the present invention. On one surface of a film substrate 1, at least a release layer 10, a metal thin film layer 20 containing a leafing aluminum powder and a binder resin, and an outermost layer A transfer layer 50 including a black adhesive layer 30 containing a black colorant in this order is provided, and the black adhesive layer 30 is adjusted so that the transmission density of the thermal transfer sheet 100 is 0.7 to 2.0. It is.
FIG. 2 shows another embodiment of the thermal transfer sheet of the present invention. On one surface of the film substrate 1, at least a release layer 10, a metal thin film layer 20 containing a leafing type aluminum powder and a binder resin, and an outermost layer. As a heat-resistant slipping layer, a transfer layer 50 including a black adhesive layer 30 containing a black colorant in this order is provided, and the other surface of the film substrate 1 has improved thermal head slidability and prevents sticking. 40 and the black adhesive layer 30 has a configuration adjusted so that the transmission density of the thermal transfer sheet 100 is 0.7 to 2.0.
Moreover, although the use shape of the thermal transfer sheet of the present invention is usually used as a continuous belt-like thermal transfer sheet, it can also be used as a single sheet.

Hereinafter, each layer constituting the thermal transfer sheet of the present invention will be described in detail.
(Film substrate)
The film substrate 1 of the thermal transfer sheet is not particularly limited as long as it is a material that can withstand the heating of the thermal head during thermal transfer recording and has desired heat conductivity, mechanical strength, and the like. The well-known material used for etc. can be used. For example, polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate, polyethylene terephthalate-isophthalate copolymer, terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer, polyethylene terephthalate-polyethylene naphthalate In addition to polyester resins such as coextruded films, polyamide resins, acrylic resins, imide resins, and cellulose films can be applied. Furthermore, it may be a plastic film such as polypropylene, polystyrene, polycarbonate, polyvinyl chloride, polyvinylidene chloride or polyimide, paper such as condenser paper or paraffin paper, and non-woven fabric. Polyethylene terephthalate, which has good heat resistance and mechanical strength, is optimal.
The film substrate may be a copolymer resin containing the above resin as a main component, a mixture (including a polymer alloy), or a laminate composed of a plurality of layers. The film substrate may be a stretched film or an unstretched film, but a film stretched in a uniaxial direction or a biaxial direction is preferable for the purpose of improving the strength.

  Moreover, as for the film base material 1, it is desirable to give the easily bonding process to the peeling layer side. Although the thickness of a film base material is suitably adjusted from points, such as the mechanical strength and heat conductivity, it is about 0.5-50 micrometers normally, Preferably it is about 2-25 micrometers. If the thickness of the base film is too thick, the heat transfer of the thermal head is poor, and if the thickness is too thin, the mechanical strength is insufficient. In the present invention, since the metal thin film layer is provided by coating instead of vapor deposition, durability required for vapor deposition is not required, and the film substrate can be made thin. For example, in the case of a polyethylene terephthalate film, 2 to 8 μm is preferable, and 3 to 6 μm is more preferable.

(Peeling layer)
In the present invention, the release layer 10 formed on one surface of the base film is separated from the film base 1 and the metal thin film layer 20 described later by peeling the thermal transfer sheet on the release layer or the release layer adjacent surface. It is a layer that enables. Usually, at least a part of the release layer 10 is transferred together with the metal thin film layer to the surface of the transfer image after transfer. Therefore, since it is located on the metal thin film layer in the state of the transfer image, it is preferable that the metal thin film layer can be seen through the metal gloss and has transparency to the extent that the metal gloss is not impaired.

  When the release layer 10 is transferred to the surface of the transfer image after transfer, the release layer 10 preferably has a low cohesive force at the time of printing so that the foil breakage at the time of printing is good. The release layer may be a layer that does not transfer at all, but in this case, it is preferable to have an undercoat layer that can protect the metal thin film layer after transfer between the release layer and the metal thin film layer described later. . When the release layer is a layer that does not transfer and transfer at all, the transfer layer of the thermal transfer sheet includes at least an adhesive layer and a metal thin film layer.

The release layer is made of a material having excellent releasability such as waxes, silicone wax, silicone resin, fluororesin, or the like, a resin having a relatively high softening point that does not melt by the heat of the thermal head, or a wax on these resins. It is formed from a resin containing a thermal release agent.
Resins with a relatively high softening point include acrylic resins, vinyl chloride-vinyl acetate copolymer resins, polyester resins, polyolefin resins, polyvinyl acetal resins, polyvinyl butyral resins, polyethylene resins, polycarbonate resins, polyarylate resins, polystyrene resins, styrene resins. Examples thereof include a non-acrylic copolymer resin, a cellulose resin, a polyvinyl alcohol resin, a polyamide resin, a polyimide resin, a norbornene resin, and mixtures, copolymers, and modified products of the exemplified resins. Among them, acrylic resin, polyolefin resin, vinyl chloride-vinyl acetate copolymer resin, polyester resin, and mixtures thereof are heat resistance, transparency, releasability from the base film side, foil breakage at the time of printing, etc. To preferred.

The release layer is preferably a thin layer so as not to reduce the sensitivity of the thermal transfer sheet. For example, the dry coating amount is preferably about 0.1 to ² g / m ² , and more preferably 0. A thickness of 3 to 1.0 g / m ² is preferred. For example, if the thickness is less than 0.1 g / m ² when the coating amount is dry, the release function as a release layer is not stable, and if it exceeds ² g / m ² , the foil breakage at the time of printing deteriorates and halftone recording Becomes difficult.

  Moreover, by including a coloring agent such as a dye or a pigment in the release layer, the unique hue of the metal thin film layer can be changed to another hue to further improve the decorativeness. For example, the metal thin film layer is provided with a colored release layer having various transparency such as yellow, red, green, blue, etc. for silver which is a unique color of the leafing type aluminum powder, thereby further improving the decorativeness. In addition, the hue and gloss of metals such as gold, copper, and bronze can be easily provided. In particular, when a colorant is contained in the release layer, a two-layer structure of a release layer mainly composed of a material having excellent releasability and a color layer mainly composed of a colorant and a resin binder can be used. is there.

(Metal thin film layer)
The metal thin film layer 20 is transferred from the thermal transfer sheet to the transfer object, and brings a metallic gloss to the transfer object. This metal thin film layer can be formed by applying a coating solution for forming a metal thin film layer in which leafing type aluminum powder is dispersed in a binder resin.

As the leafing-type aluminum powder, a leafing-type aluminum powder produced by the method described below is particularly preferable because it is excellent in metal gloss and image formation with high brightness.
1. A release surface with an embossed pattern is formed on a roll or continuous carrier sheet.
2. Aluminum is deposited on the release surface by vapor deposition in a manner that matches the embossed pattern to form an aluminum film.
3. The release surface is dissolved to separate the aluminum film and the carrier sheet from each other.
4). The separated aluminum film is subdivided into dimensions suitable for use in coating inks.

  The leafing type aluminum powder produced as described above has a deposition thickness of about 0.01 to 0.1 μm, an average particle thickness (minor axis) of 0.01 to 0.2 μm, and an average particle size (major axis). ) May have a size of about 1 to 100 μm and the surface may be treated with a resin or the like. The leafing type aluminum powder produced by the above-described manufacturing method has a surface gloss equivalent to that of an aluminum vapor deposition film as compared with a conventional aluminum paste, and therefore, a brightness close to that of the aluminum vapor deposition film can be obtained. Furthermore, since the film has a discontinuous phase between pigments, it has a diffused reflection property of light as compared with a vapor-deposited film in which the film is a continuous phase, and brightness can be imparted. Among them, the leafing type aluminum powder produced as described above has an average particle thickness (minor axis) of about 0.01 to 0.05 μm and an average particle size (major axis) of about 1 to 50 μm. It is preferable that it is excellent in metallic gloss and excellent in image formation with high brightness. The leafing type aluminum powder increases in brightness as the average particle size increases, but the transferability decreases. Conversely, when the average particle size is small, printing with low energy is possible, but there is a problem that the luminance is lowered.

  The amount of the leafing-type aluminum powder added can be arbitrarily selected in consideration of the concealability of the printed image, transfer sensitivity, luminance, and the like. The content of the leafing type aluminum powder in the metal thin film layer is preferably 10 to 500 parts by weight, more preferably 25 to 200 parts by weight, based on 100 parts by weight of the binder resin. When the amount is less than 10 parts by weight, it is necessary to increase the thickness of the metal layer in order to ensure a metallic luster, which causes problems such as a foil breakage during printing and a decrease in transfer sensitivity. When the content exceeds 500 parts by weight, there arises a problem that the fixing property to the transfer paper is lowered.

  As binder resin, polyolefin resin such as vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, polyamide resin, polyester resin, epoxy resin, polyurethane resin , Acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, petroleum resins, phenol resins, polystyrene resins, and the like. Among the above binder resins, it is preferable to use a thermoplastic resin having a glass transition temperature of 50 to 150 ° C. because of excellent transferability and film strength of the metal thin film layer. Specifically, among the above binder resins, cellulose resins, melamine resins, and acrylic resins are preferably used particularly in terms of transferability, scratching properties, heat resistance, and the like.

  In addition, a leafing type aluminum powder, a binder and, if necessary, additives such as a dispersant and an anti-settling agent can be added to the metal thin film layer. By adding these substances, the dispersibility of the leafing type aluminum powder in the metal thin film layer can be improved, and the brightness of the printed matter can be effectively improved. Moreover, you may add colorants, such as various dyes and pigments, as needed, in the range which does not inhibit the effect of this invention.

The metal thin film layer is formed by using hot melt coating, hot lacquer coating, gravure direct coating, gravure coating using a coating solution for forming a metal thin film layer in which a leafing aluminum powder, a binder and other components are dissolved or dispersed in a solvent. It can be performed by reverse coating, knife coating, air coating, roll coating, or the like. The thickness of the metal thin film layer can be arbitrarily selected in consideration of concealability and transfer sensitivity, but it is preferably 0.1 to 5.0 g / m ² , more preferably 0 in terms of coating amount during drying. ² to 2.0 g / m ² . When the coating amount during drying is less than 0.1 g / m ² , it is difficult to obtain a uniform coating film due to film formation problems. When the thickness exceeds 5.0 g / m ² , print transfer is performed. In this case, high energy is required, and printing may be possible only with a special thermal transfer printer.
From the viewpoint of realizing a thin transfer layer, the thickness of the metal thin film layer is preferably 0.05 to 0.2 μm, and more preferably 0.1 to 0.15 μm.

(Black adhesive layer)
The black adhesive layer 30 located on the outermost surface of the thermal transfer sheet of the present invention contains a black colorant so that the transmission density of the thermal transfer sheet is 0.7 to 2.0. The black adhesive layer 30 in the present invention improves the transfer sensitivity to the transfer body and the adhesion to the transfer body, and also improves the metallic luster of the printed material of the thermal transfer sheet of the present invention and the concealability to the ground. Have The black adhesive layer contains at least a binder resin having an adhesive function and a black colorant. In particular, the black adhesive layer preferably contains a black colorant so that the transmission density of the thermal transfer sheet is 1.0 to 2.0.

  As the binder resin having an adhesive function, a heat-bonding adhesive that is melted or softened by heat and bonded can be applied. For example, ionomer resins, acid-modified polyolefin resins, ethylene- (meth) acrylic acid copolymers, ethylene- (Meth) acrylic acid ester copolymers, polyester resins, polyamide resins, vinyl chloride resins, vinyl acetate resins, vinyl chloride-vinyl acetate copolymers, acrylic / methacrylic resins including acrylic ester resins, etc. (Meth) acrylic resin, maleic resin, butyral resin, alkyd resin, polyethylene oxide resin, phenolic resin, urea resin, melamine resin, melamine-alkyd resin, cellulose resin, polyurethane resin, polyvinyl ether resin, Silicone resin, rubber resin, etc. can be applied. The resin used in combination with single or multiple. The resin for these adhesive layers is selected in consideration of the affinity with the transfer material. In general, (meth) acrylic resins, butyral resins, polyester resins, vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate-maleic acid copolymers are suitable in terms of adhesive strength and the like. is there.

  Further, wax or a mixture of wax and thermoplastic resin may be used. The waxes include carnauba wax, paraffin wax, microcrystalline wax, ester wax, Fuchter-Tropsch wax, various low molecular weight polyethylene, wood wax, beeswax, whale wax, ibota wax, wool wax, shellac wax, candelilla wax, petro Various conventionally known waxes such as lactam, partially modified wax, fatty acid ester, and fatty acid amide can be used. In particular, the thermoplastic resin of the ethylene copolymer and the wax are contained in the adhesive layer in the form of fine particles, respectively, so that the cohesive force at the time of thermal transfer can be kept low, and the foil breakability at the time of printing is generally improved. Recording with high resolution and high sensitivity. In order to make the adhesive layer contain in the form of fine particles, a dispersion or emulsion liquid of these fine particles may be applied as an adhesive layer and dried below the melting point or softening point of the fine particles. Note that the fine particle shape does not mean only a spherical shape, but is a state in which the substantially spherical independent fine particles in the emulsion are loosely bonded to each other so that they can be separated into the original fine particle units by an external force while deforming the shape by moderate heat. It means the fine particles in

  On the other hand, examples of the black colorant include inorganic carbon black, graphite, iron trioxide, and organic cyanine black. Further, the black colorant may be a black colorant that is appropriately mixed with a colorant, such as mixing yellow, magenta, and cyan dyes. Especially, it is preferable to use black pigments, such as carbon black, from the point which is easy to achieve the permeation | transmission density | concentration of a thermal transfer sheet 0.7-2.0 with a small addition.

  In the black adhesive layer of the present invention, the content of the black colorant is appropriately adjusted depending on the black colorant used so that the transmission density of the thermal transfer sheet is 0.7 to 2.0. For example, as a guideline when using a black pigment such as carbon black, it is preferable that the black colorant is contained in the black adhesive layer in the range of 5 wt% to 20 wt%, particularly 10 wt% to 15 wt%. It is preferable to contain in the range.

The black adhesive layer 30 is formed by applying a composition obtained by dispersing or dissolving the above-mentioned heat-adhesive resin and black colorant in a solvent by a known coating method or printing method and drying. As a coating method or a printing method, a method similar to the method described in the metal foil film layer can be applied. Drying may be brushed as necessary to improve transferability. The thickness of the adhesive layer is usually about 0.2 to 1.5 μm, preferably 0.4 to 0.8 μm. The dry coating amount is usually about 0.2 to 1.5 g / m ² , preferably 0.4 to 0.8 g / m ² . If the thickness of the adhesive layer is less than this range, the adhesive strength with the transferred material will be insufficient and drop off, and if it exceeds this range, the adhesive effect will be sufficient, but the effect will not change, so it will be costly. In addition, the heat of the thermal head is wasted. Furthermore, additives such as a filler, a plasticizer, a colorant, and an antistatic agent may be appropriately added to the adhesive layer as necessary. As the filler, extender pigments such as silica and calcium carbonate can be applied. In particular, addition of extender pigments improves foil breakage. As the antistatic agent, nonionic surfactants, anionic surfactants, cationic surfactants, polyamides, acrylic acid derivatives, and the like can be applied.

  In the present invention, the total thickness of the transfer layer transferred to the transfer target is preferably 1 μm to 2 μm, and more preferably 1 μm to 1.4 μm. In the case of such a thin transfer layer, it is preferably used when transferring a plurality of colors in an overlapping manner. The transfer layer usually includes at least the release layer, the metal thin film layer, and the black adhesive layer, but may include other layers, and may not include the release layer.

(Heat resistant slipping layer)
As shown in the cross-sectional view of FIG. 2, the thermal transfer sheet of the present invention has a heat resistant slipping layer 40 on the other surface of the film substrate 1 in order to prevent adverse effects such as sticking and printing wrinkles due to the heat of the thermal head. May be provided. 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 acetate propionate resin, cellulose acetate Butyrate resin, cellulose acetate hydrodiene phthalate resin, cellulose acetate resin, aromatic polyamide resin, polyimide resin, polyamideimide resin, poly Boneto resins, and chlorinated polyolefin resins.

  The slipperiness imparting agent added to or overcoating the heat resistant slipping layer made of these resins includes phosphate ester, metal soap, silicone oil, graphite powder, silicone graft polymer, fluorine graft polymer, acrylic silicone graft polymer, acrylic. Examples thereof include silicone polymers such as siloxane and arylsiloxane. Preferably, it is a layer made of a polyol, for example, a polyalcohol polymer compound, a polyisocyanate compound, and a phosphate ester compound, and a filler may be added. More preferred.

The heat-resistant slip layer is prepared by dissolving or dispersing the above-described resin, slipperiness-imparting agent, and filler in an appropriate solvent on the base sheet to prepare a heat-resistant slip layer coating solution. This can be formed by applying and drying by a forming means such as a gravure printing method, a screen printing method, or a reverse roll coating method using a gravure plate. The coating amount of the heat-resistant slip layer is sufficient as long as the anti-fusing and lubricating the like are fulfill, ^{usually, 0.1g / m 2 ~3.0g / m} 2 is preferred solids.

  In addition, the thermal transfer sheet of the present invention may be further provided with other configurations such as detection marks and the like provided on the thermal transfer sheet.

  The thermal transfer sheet of the present invention configured as described above is most suitable for a thermal printer using a thermal head, but can also be used for molding such as roll thermal transfer, hot stamping transfer foil, and in-mold molding. Since the thermal transfer sheet of the present invention can make the transfer layer thin, it is particularly suitable for imparting a metallic luster to multi-color overprinting.

  The material to be transferred of the thermal transfer sheet of the present invention is not particularly limited. For example, natural fiber paper, coated paper, tracing paper, plastic film that is not deformed by heat during transfer, glass, metal, ceramics, wood, cloth, etc. Any one is acceptable. As for the shape of the transfer object, containers such as cards, cartons, and cases, tags, bookmarks, posters and other single sheets, POP supplies, cosmetics, watches, lighters and other accessories, envelopes, report paper and other stationery, There is no limitation on the type of building materials, panels, emblems, keys, cloth, clothing, footwear, bags, cellular phones, televisions, electrical appliances such as OA equipment. At least a part of the medium of the transferred material is colored, printed or otherwise decorated, and / or, if necessary, other layers such as a primer layer, an adhesive layer, and a protective layer are provided between the layers and the surface. Also good.

Next, the present invention will be described more specifically with reference to examples and comparative examples. In the text, “part” or “%” is based on weight unless otherwise specified.
Example 1
As a base film, on one surface of a polyethylene terephthalate film having a thickness of 4.5 μm, a release layer coating liquid having the following composition is applied by gravure coating so that the dry coating amount is 0.3 g / m ² . Dry to form a release layer. Furthermore, on the release layer, a metal thin film layer coating solution having the following composition is applied by gravure coating so that the dry coating amount is 0.3 g / m ² , and dried to form a metal thin film layer. Furthermore, on the metal thin film layer, a black adhesive layer coating liquid having the following composition is applied by gravure coating so that the dry coating amount is 0.4 g / m ² and dried to form a black adhesive layer. The thermal transfer sheet of Example 1 was produced. The thickness of the metal thin film layer in the thermal transfer sheet was 0.11 μm, and the total thickness of the transfer layer was 1 μm. In addition, the heat resistant layer coating liquid having the following composition was applied to the other surface of the base film in advance by gravure coating so that the dry coating amount was 0.3 g / m ² and dried. Had formed.

[Coating liquid for release layer]
Acrylic resin (Mitsubishi Rayon Co., Ltd., trade name: BR83) 89 parts vinyl chloride-vinyl acetate copolymer (Nissin Chemical Industry Co., Ltd., trade name: Solbin-C) 10 parts Polyester (Toyobo Co., Ltd.) Name: Byron 200) 1 part methyl ethyl ketone / toluene (weight ratio 2/1) 200 parts

[Metal thin film layer coating solution]
Fine wrap Super metallic silver (Dainippon Ink Co., Ltd., manufactured on a carrier sheet provided with a release layer by vapor deposition, peeling the aluminum film from the carrier sheet and subdividing it Contains aluminum powder)

[Black Adhesive Layer Coating Liquid]
Carbon black 5.2 parts acrylic resin (trade name: BR87 manufactured by Mitsubishi Rayon Co., Ltd.) 20.3 parts vinyl chloride-vinyl acetate copolymer (trade name: Solbin-C manufactured by Nissin Chemical Industry Co., Ltd.) 5 parts methyl ethyl ketone 36 parts toluene 36 parts

[Coating fluid for heat-resistant layer]
Styrene acrylonitrile copolymer resin 11 parts linear saturated polyester resin 0.3 part zinc stearyl phosphate 6 parts melamine resin powder 3 parts methyl ethyl ketone 80 parts

[Transmission density of thermal transfer sheet]
The transmission density of the thermal transfer sheet was measured with the following measuring instrument in accordance with JIS K 7653-1988.
Measuring instrument: Macbeth TR924, manufactured by Macbeth
As a result, the transmission density of the thermal transfer sheet of Example 1 was 0.75.

(Example 2)
On the metal thin film layer, a black adhesive layer coating solution having the same composition as in Example 1 is applied by gravure coating so that the dry coating amount is 0.74 g / m ² and dried to form a black adhesive layer. A thermal transfer sheet was produced in the same manner as in Example 1 except that. The total thickness of the transfer layer in the thermal transfer sheet was 1.4 μm.
The transmission density of the thermal transfer sheet of Example 2 was measured in the same manner as in Example 1, and was 1.1.

(Comparative Example 1)
On the metal thin film layer, an adhesive layer coating solution having the following composition is applied by gravure coating to a dry coating amount of 0.4 g / m ² and dried to form an adhesive layer that does not contain a black colorant. A thermal transfer sheet was produced in the same manner as in Example 1 except that. The total thickness of the transfer layer in the thermal transfer sheet was 1 μm.
When the transmission density of the thermal transfer sheet of Comparative Example 1 was measured in the same manner as in Example 1, it was 0.38.
[Coating liquid for adhesive layer]
Acrylic resin (Mitsubishi Rayon Co., Ltd., trade name: BR87) 20.3 parts Vinyl chloride-vinyl acetate copolymer (Nissin Chemical Industry Co., Ltd., trade name: Solbin-C) 2.5 parts Methyl ethyl ketone 36 parts Toluene 36 copies

(Comparative Example 2)
On the metal thin film layer, a black adhesive layer coating liquid having the same composition as in Example 1 is applied by gravure coating so that the dry coating amount is 0.2 g / m ² and dried to form a black adhesive layer. A thermal transfer sheet was produced in the same manner as in Example 1 except that. The total thickness of the transfer layer in the thermal transfer sheet was 0.86 μm.
The transmission density of the thermal transfer sheet of Comparative Example 2 was measured in the same manner as in Example 1, and was 0.58.

Using the thermal transfer sheets of Examples and Comparative Examples described above, printing was carried out under the following printing conditions, and the printed materials were evaluated for glossiness and hiding properties by the following evaluation methods. The evaluation results are shown in Table 1 below.
(Printing conditions)
Using a commercially available label printer (resolution: 300 dpi, printing speed: 100 mm / sec), the image to be transferred is an image receiving paper on which an image is recorded by the sublimation transfer method, and the thermal transfer sheets of Examples and Comparative Examples are used for testing. Patterns were printed and evaluation samples were created.

(Evaluation method for metallic luster)
Under the above printing conditions, the obtained printed matter was visually evaluated for metallic gloss. Evaluation was made according to the following criteria.
○: Good metallic luster and good appearance.
(Triangle | delta): A metallic luster feeling is not so high and it does not look very good.
X: The metallic luster is low and it does not look good.

(Concealment evaluation method)
Under the above-described printing conditions, the obtained printed matter is visually checked to see if the image on the background of the printed portion can be seen through, and the hiding property is evaluated. Evaluation was made according to the following criteria.
A: The background image of the printed material cannot be seen through, and the hiding property is particularly excellent.
◯: The background image of the printed material is not seen through, and the concealability is good.
Δ: The image of the background of the printed matter is slightly transparent, and the image is insufficiently concealed.
X: The image of the background of the printed matter can be seen through, and the image is very insufficient in concealment.

  From the above evaluation results, Examples 1 and 2 according to the present invention in which a transfer layer including a black adhesive layer containing a black colorant as an outermost layer in this order is provided and the transmission density is 0.7 to 2.0. This thermal transfer sheet has a thin metal layer, but has a high metallic luster and a high concealment property for the background, and it has been revealed that the thermal transfer sheet is suitable for multi-color overlay transfer. On the other hand, in Comparative Example 1 which has the same coating amount of the adhesive layer but does not contain a black colorant and the thermal transfer sheet has a transmission density of 0.38, the background image of the printed matter is seen through. As a result, an image having a very poor concealment property, a low metallic luster, and an unsatisfactory print was obtained. Further, in Comparative Example 2 that contained a black colorant but had a thermal transfer sheet transmission density of 0.58, the image of the background of the printed material was slightly seen through, resulting in an image with insufficient concealment, and A printed product with a metallic gloss that was not so high and did not look very good was obtained.

It is a schematic sectional drawing which shows one embodiment which is the thermal transfer sheet of this invention. It is a schematic sectional drawing which shows another one Embodiment which is the thermal transfer sheet of this invention. It is a schematic sectional drawing explaining the melt transfer system of a thermal transfer sheet. It is a schematic sectional drawing explaining the overlap transfer of the thermal transfer sheet of a melt transfer system. It is a schematic sectional drawing explaining the problem of the overlap transfer of the thermal transfer sheet of a melt transfer system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 10 Peeling layer 20 Metal layer 30 Adhesive layer 40 Heat resistant slipping layer 50 Transfer layer 51 Transfer layer of the first color 52 Transfer layer of the second color 60 Transfer object 70 Heating 80 Gap due to steps 81 Location not transferred to the boundary portion 100 Thermal transfer sheet

Claims (6)

  On one surface of the film substrate, a transfer layer including at least a release layer, a metal thin film layer containing a leafing type aluminum powder and a binder resin, and a black adhesive layer containing a black colorant as an outermost layer in this order is provided. A thermal transfer sheet having a transmission density of 0.7 to 2.0.   The thermal transfer sheet according to claim 1, wherein the total thickness of the transfer layer is 1 μm to 2 μm.   The thermal transfer sheet according to claim 1 or 2, wherein the black adhesive layer contains 5 to 20% by weight of a black colorant. The black adhesive layer is provided at 0.4g ^{/ m 2} ~0.8g ^/ m 2 on a solids thermal transfer sheet according to any one of claims 1 to 3.   The leafing type aluminum powder is an aluminum powder produced by forming an aluminum film by vapor deposition on a carrier sheet provided with a release layer, peeling the aluminum film from the carrier sheet, and then subdividing the aluminum sheet. Item 5. The thermal transfer sheet according to any one of Items 1 to 4.   The thermal transfer sheet according to any one of claims 1 to 5, wherein a heat-resistant slipping layer is further provided on the other surface of the film substrate on which the transfer layer is not provided.

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