JP2009214339A - Thermal transfer sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal transfer sheet capable of printing by following a three-dimensional structure and providing an excellent metallic luster on its printed article. <P>SOLUTION: The thermal transfer sheet is prepared by providing successively at least an undercoat layer with at least a releasing function, a metal luster layer provided by coating, and an adhesive layer on one face of a film substrate, and the surface roughness (Ra) of the surface on the metal luster layer side of the undercoat layer is ≤0.1 μm. <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. Such a thermal transfer sheet has a metallic gloss including a metal vapor-deposited layer by heating with a thermal transfer printer having a heating device such as a thermal head from the base film side with the adhesive layer side facing the transfer target. Etc. are transferred to the transfer medium. Patent Document 2 discloses a thermal transfer sheet characterized in that a metallic layer containing at least leafing type aluminum powder is provided on one surface of a base film.

  In recent years, due to high design properties, there is an increasing demand for electrical characters, automobile parts, furniture, interior decorations, and the like that have metallic glossy characters, designs and appearances. However, the conventional thermal transfer sheet imparting metallic luster is insufficient in metallic luster, the printed material cannot hold a mirror surface, and if it is transferred to a three-dimensional structure instead of a flat surface, the three-dimensional structure There is a problem that a printed matter having a metallic luster breaks without being able to follow the above.

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

  Accordingly, in order to solve the above-described problems, an object of the present invention is to provide a thermal transfer sheet that can be printed following a three-dimensional structure and that the printed matter has an excellent metallic luster.

  In order to solve the above-mentioned problems, the present invention provides at least an undercoat layer having at least a peeling function, a metallic luster layer provided by coating, and an adhesive layer on one surface of a film substrate in order. Provided is a thermal transfer sheet in which the surface roughness (Ra) of the surface of the metallic gloss layer side of the layer is 0.1 μm or less.

  According to the present invention, the metallic gloss layer provided by coating is used as the metallic gloss layer for imparting metallic gloss, and the surface roughness (Ra) of the metallic gloss layer side surface of the undercoat layer of the metallic gloss layer By setting the thickness to 0.1 μm or less, it is possible to obtain a thermal transfer sheet that can be printed following a three-dimensional structure and that has an excellent metallic luster.

  In the thermal transfer sheet of the present invention, it is preferable that the metallic gloss layer provided by the coating contains scaly metal powder and / or metal nanocolloid particles because the metallic gloss feeling of the printed matter is excellent. .

  In the thermal transfer sheet of the present invention, the undercoat layer contains a thermosetting resin and / or a photocurable resin, so that the mirror surface of the metallic gloss layer is destroyed when the thermal transfer sheet is printed or when the printed matter is retransferred. This is preferable because it is difficult and the metallic gloss of the printed material is kept excellent.

  In the thermal transfer sheet of the present invention, the undercoat layer comprises two or more layers, and contains at least a release layer on the film substrate side and a thermosetting resin and / or a photocurable resin on the metallic luster layer side. It is preferable that a mirror surface layer having roughness is included because the mirror surface of the metallic gloss layer is not easily destroyed during printing of the thermal transfer sheet or retransfer of the printed material, and the metallic gloss feeling of the printed material is maintained excellent. .

  In the thermal transfer sheet of the present invention, when the mirror surface layer has a softening point of 130 ° C. or more, the mirror surface degree of the layer that forms the structure of the light reflecting surface is hardly broken, and as a result, when the thermal transfer sheet is printed. In addition, the mirror surface of the metallic gloss layer is not easily broken during retransfer of the printed material, and this is preferable because the metallic gloss feeling of the printed material is maintained excellent.

  In the thermal transfer sheet of the present invention, the metal gloss layer side surface of the undercoat layer is formed by pressing with a surface having a surface roughness (Ra) of 0.1 μm or less. The surface of the glossy layer side surface is easy to make a mirror surface, and is particularly preferable because a high metallic luster is obtained.

  The thermal transfer sheet of the present invention can be printed following a three-dimensional structure, and has the effect that the printed matter has an excellent metallic luster. Moreover, unlike the case of the conventional metal vapor deposition layer, the thermal transfer sheet of the present invention can reduce the thickness of the substrate film and can increase the printing resolution. Furthermore, the thermal transfer sheet of the present invention can form a metallic gloss layer in a desired pattern, and can easily produce a thermal transfer sheet in which other dye layers and a metallic gloss layer are arranged in order.

  In the thermal transfer sheet according to the present invention, at least one undercoat layer having a peeling function, a metallic gloss layer provided by coating, and an adhesive layer are sequentially provided on one surface of the film substrate, and the metallic gloss of the undercoat layer is provided. The surface roughness (Ra) of the layer side surface is 0.1 μm or less.

In the thermal transfer sheet of the present invention, a metallic gloss layer provided by coating is used as a metallic gloss layer for imparting a metallic gloss, and the surface roughness of the metallic gloss layer side surface of the undercoat layer of the metallic gloss layer ( Ra) is 0.1 μm or less.
In the present invention, the metallic luster layer provided by coating is used as the metallic luster layer for imparting metallic luster, so that the metallic luster layer is usually formed by holding a fine metal powder together with a binder component. Thus, it is possible to obtain a printed matter having a metallic luster that follows the three-dimensional structure without causing cracks even when transferred to the surface. Unlike the case of a metal vapor deposition layer, since the component which shows a metallic luster becomes a microparticle, it itself does not cause the crack of a metallic luster layer.
Also, by using a metallic luster layer provided by coating, it is possible to reduce the thickness of the base film unlike a conventional metal vapor deposition layer. When the base material is thick, the printability is drastically reduced. However, since the thermal transfer sheet according to the present invention can reduce the thickness of the base film, the printing resolution can be increased.
Furthermore, since the metallic gloss layer can be formed into a desired pattern by using the metallic gloss layer provided by coating, it is possible to easily produce a thermal transfer sheet in which other dye layers and the metallic gloss layer are arranged in a plane order. Can do. Furthermore, the present inventor found that the surface of the layer serving as the base of the metallic luster layer was rough and was provided on the surface of the metallic luster layer, which was insufficient in the conventional thermal transfer sheet imparting metallic luster. It was found that the metallic luster layer was affected by irregularities on the surface of the base and caused white light scattering. In the thermal transfer sheet of the present invention, the surface roughness (Ra) on the surface of the metallic gloss layer of the undercoat layer is 0.1 μm or less, so that the undercoat layer is excellent in surface smoothness like a mirror surface. Therefore, the surface of the metallic gloss layer provided on the undercoat layer is also excellent in smoothness, and the reflectance of the printed product in the metallic gloss layer is improved, and in particular, a printed product with a high metallic gloss feeling can be obtained. Can do.

FIG. 1 is one embodiment of the thermal transfer sheet of the present invention, and is an undercoat layer on one surface of a film substrate 1 having at least a peeling function and the surface on the metallic gloss layer side having the surface roughness. 10, the metallic gloss layer 20 provided by coating, and the adhesive layer 30 are formed, and the surface roughness (Ra) of the metallic gloss layer side surface 15 of the undercoat layer 10 is 0.1 μm or less.
FIG. 2 shows another embodiment of the thermal transfer sheet of the present invention. On one surface of the film substrate 1, a release layer 11 having a release function and a thermosetting resin and / or photocurable resin on the metallic gloss layer side. An undercoat layer 10 comprising two layers of a mirror surface layer 12 containing a resin and having the above surface roughness, a metallic gloss layer 20 provided by coating, and an adhesive layer 30 are formed on the other surface of the film substrate 1 A heat-resistant slip layer 40 is provided to improve the slidability of the thermal head and prevent sticking, and the surface roughness (Ra) of the metallic gloss layer side surface 15 of the undercoat layer 10 (mirror surface layer 12) is 0.1 μm or less. This is the configuration.
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 undercoat 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 metallic luster layer is provided by coating rather than vapor deposition, the durability of the substrate necessary 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.

(Underlayer)
In the present invention, the undercoat layer 10 is a layer that is provided on one surface of the substrate film and has at least a peeling function, and a metallic gloss layer described later is provided in contact with the undercoat layer. The undercoat layer of the present invention has a surface roughness (Ra) of the metal gloss layer side surface of 0.1 μm or less. The surface roughness (Ra) in the present invention is measured in accordance with JIS B0601, and can be determined by a surface roughness shape measuring machine (for example, Surfcom 1400, manufactured by Tokyo Seimitsu).

The undercoat layer 10 is a layer in which all or part of the thickness direction is transferred from the thermal transfer sheet to the transfer target during transfer recording to form the outermost surface of the printed material. In the case of partial transfer or complete transfer, it is preferable that the cohesive force at the time of printing is low so that the foil breakage at the time of printing is good.
The undercoat layer may be composed of one layer or two or more layers as long as it has at least the peeling function and has the specific surface roughness. When the undercoat layer is composed of one layer, the undercoat layer is formed by a method of forming a mirror layer using the material described in the later-described release layer so as to have at least the functions of the later-described release layer 11 and the mirror layer 12. The subbing layer is formed by a method of forming a mirror surface layer by appropriately mixing and using a release material used for a release layer in a material described in a mirror surface layer described later. In the case where the undercoat layer is composed of one layer and has both a release layer and a mirror layer, it is preferable because the layer structure is simple and the followability to the three-dimensional structure is good. In addition, when the undercoat layer is composed of one layer, the overall layer thickness can be reduced, so that the foil breakage is good at the time of printing, and it becomes easy to form a high-definition metallic gloss pattern with high resolution, and at the time of production. There is also an advantage of cost reduction.
In particular, when the undercoating layer is composed of one layer, and the undercoating layer having the peeling function contains a thermosetting resin and / or a photocurable resin, when the thermal transfer sheet is printed, The mirror surface of the metallic gloss layer is less likely to be destroyed at the time of retransfer, and this is preferable from the viewpoint that the metallic gloss of the printed material is maintained excellent.

  On the other hand, it is preferable that the undercoat layer is composed of two or more layers from the viewpoint of easily optimizing the peeling function and the surface roughness of the surface of the metallic gloss layer with respect to the printing conditions and the transfer target. Among them, the undercoat layer is composed of two or more layers, at least a release layer on the film base side, and a mirror surface layer having a surface roughness containing a thermosetting resin and / or a photocurable resin on the metallic luster layer side. If it is included, the mirror surface of the metallic gloss layer is difficult to be destroyed during printing of the thermal transfer sheet or retransfer of the printed material, which is preferable because the metallic gloss of the printed material is maintained excellent.

Hereinafter, each of the peeling layer 11 and the mirror surface layer 12 will be described more specifically.
(Peeling layer)
The release layer 11 is a layer that allows the thermal transfer sheet to be peeled off at the release layer or the adjacent surface of the release layer, so that the film substrate and the metallic gloss layer 20 described later can be separated. The release layer may be a layer that does not transfer and transfer at all. 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.
Examples of relatively high softening point resins include acrylic resins, polyurethane resins, polyvinyl acetal resins, polyester resins, polystyrene resins, polycarbonate resins, polyether resins, nitrocellulose, ethyl cellulose, cellulose derivatives, and other celluloses. Polyether ketones such as chlorinated polyolefin resins, polyarylate resins, norbornene-based hydrogenated resins, polyimide resins, polyamideimide resins, polyetheretherketone resins (PEEK) and polyetherketone resins (PEK) , Polyethersulfone resin, polysulfone resin, polyphenylene oxide resin and the like, and these may be used alone or as a mixture. As components for improving the adhesion to the transferred material after transfer, a halogenated resin such as polyvinyl chloride or polyvinylidene chloride, polyvinyl acetate, a vinyl chloride-vinyl acetate copolymer, an ethylene-vinyl acetate copolymer are used. A vinyl resin such as a polymer or polyacrylic acid ester, a copolymer resin of an olefin such as ethylene or propylene and another vinyl polymer, a cellulose resin such as an ionomer or cellulose diastase, a polycarbonate or the like may be added.

Among these, when an acrylic resin is used, it is preferable because a printed material with high durability that does not cause image collapse even under a severe environment can be formed.
In particular, it is preferable to use a mixture of an acrylic resin and a vinyl resin such as a polyester resin or a vinyl chloride-vinyl acetate copolymer because the adhesion between the release layer 11 and the film substrate 1 is excellent. .

The thickness of the release layer is generally in the range of 0.1 to 10 g / m ^{2 in} terms of the coating amount at the time of drying. When it is less than 0.1 g / m ^2, it does not function as a release layer, and when it exceeds 10 g / m ² , foil breakage at the time of printing is deteriorated, and particularly halftone recording cannot be performed well, and the foil is retained. It may cause a decrease in the quality of the product and make it unusable.

(Mirror surface layer)
The mirror surface layer 12 in the present invention is a layer that realizes a surface roughness (Ra) of 0.1 μm or less on the surface of the metallic luster layer side surface of the undercoat layer of the present invention. The mirror surface layer 12 is usually transferred to a transfer object together with a metallic gloss layer to be described later after transfer, and is positioned on the metallic gloss layer so as to be in close contact with the metallic gloss layer and become a component of a printed matter. . Therefore, the mirror surface layer in the present invention has a function of enhancing the metallic luster of the metallic luster layer provided in contact with the first, but further, by heat at the time of printing and / or retransfer after printing, It has a function of protecting the surface of the metallic luster layer having a high metallic luster from being destroyed. Since it is located on the upper layer of the metallic gloss layer and becomes a constituent element of the printed matter, it is necessary to have transparency that allows at least the metallic gloss of the metallic gloss layer to be seen through.

  As a material constituting the mirror surface layer 12, thermoplastic resin such as polyvinyl chloride, acrylic resin (eg, polymethyl (meth) acrylate), polystyrene, polycarbonate, thermosetting resin, photocurable resin, or the like is used. it can. Examples of the thermosetting resin include unsaturated polyester resins, melamine resins, epoxy resins, and urethane resins. In addition, what a hardening reaction advances at normal temperature is also contained in a thermosetting resin. Moreover, as a photocurable resin, polyester (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, polyether (meth) acrylate, polyol (meth) acrylate, melamine (meth) acrylate, triazine acrylate, Polymerization initiators and sensitizers were added to the appropriate mixture of unsaturated ethylene oligomers and unsaturated ethylene monomers such as epoxy-modified (meth) acrylate, urethane-modified (meth) acrylate, and (meth) acryl-modified polyester. Examples thereof include compositions. Moreover, you may mix thermoplastic resins, such as a polyvinyl chloride, an acrylic resin (for example, polymethyl (meth) acrylate), a polystyrene, a polycarbonate, with a thermosetting resin and / or a photocurable resin. In the present specification, “(meth) acryl” means “acryl and / or methacryl”, and “(meth) acrylate” means “acrylate and / or methacrylate”.

  In the thermal transfer sheet of the present invention, the mirror surface layer contains the thermosetting resin and / or the photocurable resin as described above, so that the mirror surface of the metallic gloss layer can be used when the thermal transfer sheet is printed or when the printed matter is retransferred. This is preferable because it is difficult to be destroyed and the metallic gloss of the printed matter is kept excellent. When the mirror surface layer contains the thermosetting resin and / or the photocurable resin as described above, the printed matter has excellent durability such as chemical resistance, light resistance, and weather resistance. In the mirror surface layer of the present invention, a urethane resin is particularly preferable as the thermosetting resin, and a combination of polyol (meth) acrylate, urethane (meth) acrylate and a curing agent is preferable. Moreover, it is preferable that a photocurable resin is used for a mirror surface layer, and the combination of urethane-modified (meth) acrylate and a curing agent is particularly preferable.

  In the thermal transfer sheet of the present invention, the mirror layer has a softening point of 130 ° C. or more, so that the mirror surface of the metallic gloss layer is difficult to be destroyed during printing of the thermal transfer sheet or retransfer of the printed matter, and the metal of the printed matter. It is preferable from the viewpoint that glossiness is maintained excellent.

The thickness of the mirror surface layer is usually 0.1 to 20 g / m ^{2 in} coating amount from the point of having a protective function of the metallic gloss layer in addition to the function of smoothing the base surface of the metallic gloss layer. It is preferable to provide in a range. When the thickness is less than 0.1 g / m ^2, it is difficult to function as a mirror layer, and when it exceeds 20 g / m ² , the foil breakage at the time of printing deteriorates and it is difficult to be suitable for halftone recording. In addition, for example, cyan, magenta, yellow, black, and other colorants such as known dyes or pigments can be appropriately mixed in the mirror surface layer for the purpose of coloring the metallic luster layer. In addition to the mirror layer, additives can be blended as necessary. Examples of the additive include an antioxidant, an ultraviolet absorber, a lubricant, an antifogging agent, an antifogging agent, a plasticizer, a near infrared absorber, and an antistatic agent.

(Method for forming mirror layer)
The mirror surface layer used in the present invention is formed using a mirror surface layer forming composition obtained by dissolving or dispersing a material forming the mirror surface layer in an organic solvent. The mirror surface layer forming composition may be, for example, a polyfunctional monomer or oligomer, a release agent, an organometallic coupling agent, a photoinitiator, etc. It is obtained by adding an additive and dissolving or dispersing it in an organic solvent.
In order to make the mirror layer a layer having excellent surface smoothness such that the surface roughness (Ra) on the surface of the metallic luster layer is 0.1 μm or less, for example, the following method can be suitably used.
1) Method of smoothly applying the mirror surface layer forming composition 2) Method of forming the mirror surface layer forming composition by applying pressure on the surface having a surface roughness (Ra) of 0.1 μm or less.

(1) Method of smoothly applying the mirror surface layer forming composition On the release layer or the substrate film by a coating method or a printing method of smoothly applying the mirror surface layer forming composition to the mirror surface layer forming composition. Apply to and dry. As a coating method or a printing method for smoothly coating the mirror surface layer forming composition so that the surface roughness (Ra) is 0.1 μm or less, for example, gravure direct coating, gravure reverse coating, and the like can be applied.
After coating smoothly, photocuring or thermosetting is performed as necessary. The light may be classified according to the quantum energy of the electromagnetic wave, but in this specification, all ultraviolet rays (UV-A, UV-B, UV-C), visible light, gamma rays, X-rays, electron rays are used. Is defined as including. Accordingly, ultraviolet light (UV), visible light, gamma ray, X-ray, electron beam, or the like can be applied as light, but ultraviolet light (UV) is preferable, and ultraviolet light having a wavelength of 300 to 400 nm is optimal. The photo-curing resin that is cured by light may contain a photopolymerization initiator and / or a photopolymerization accelerator in the case of ultraviolet curing, and may not be added in the case of high-energy electron beam curing. Can be cured even by thermal energy.

(2) Method of forming by applying a mirror surface layer forming composition and then pressing the surface with a surface having a surface roughness (Ra) of 0.1 μm or less. In the present invention, the surface of the undercoat layer (mirror surface layer) on the metallic luster layer side The surface roughness (Ra) is formed by pressing on a surface having a surface roughness of 0.1 μm or less, and the smoothness of the surface of the undercoat layer on the surface of the metallic gloss layer can be easily increased. Especially, it is preferable from the point that a high metallic luster feeling can be obtained.
The method of applying the mirror surface layer forming composition in this method does not necessarily require high smoothness, and a known coating method or printing method can be appropriately used. As the coating method, for example, gravure direct coating, gravure reverse coating, knife coating, air coating, roll coating, reverse roll coating, transfer roll coating, gravure coating and the like can be applied. After coating of the mirror surface layer forming composition, it is appropriately dried to obtain a coating film.

  As a method of pressing with a surface having a surface roughness (Ra) of 0.1 μm or less, a surface having a surface roughness (Ra) of 0.1 μm or less is usually formed on the coating film surface of the mirror surface layer forming composition. The stamper (metal plate or resin plate) that has been formed is pressure-bonded, and the surface having a surface roughness (Ra) of 0.1 μm or less is formed (replicated) on the coating surface of the mirror surface layer-forming composition, This is done by peeling off the stamper. The method of commercial replication uses a mold or resin type stamper, and after pressure-bonding to the coating film surface of the mirror surface layer forming composition to replicate the surface having a surface roughness (Ra) of 0.1 μm or less, A surface having a surface roughness (Ra) of 0.1 μm or less is replicated by irradiating light or by irradiating the stamper with light during pressure bonding and then removing the stamper. This commercial duplication can be carried out continuously on the coating film of the long mirror surface layer forming composition.

  When a photocurable resin is used as a material for forming the mirror surface layer, light is irradiated to cure the photocurable resin during or after the press bonding with the stamper. When light irradiation is performed during pressure bonding with a stamper, the back surface of the coating film of the mirror surface layer-forming composition (the stamper is pressure-contacted) with the stamper pressed against the coating film surface of the mirror surface layer-forming composition Photocuring may be performed by irradiating light from a surface opposite to the side).

  As a method of replicating the mirror surface on the coating film surface of the mirror surface layer-forming composition by pressing the surface with a surface roughness (Ra) of 0.1 μm or less, a particularly preferred example is a semi-dry replication method (SD replication method). It is a method called. In the semi-dry duplicating method, the duplicating device is provided with a pair of main body frames fixed to a bed, and a sheet feeding device, a transfer device, an irradiation device, and a winding device are sequentially arranged. Consists of a winding device. As shown in FIG. 3, the transfer device includes a plate cylinder 60 (with a surface roughness (Ra) on a roller surface of 0.1 μm or less on a roller surface) in which a shaft is rotatably supported by a bearing fixed to a central portion of a main body frame. And a pressure cylinder 62 rotatably supported by a pair of arms, and a pressurizing mechanism. From the sheet feeder, a mirror surface forming sheet 100 comprising a heat-resistant slipping layer (if necessary) / base material / peeling layer / mirror surface forming layer is fed out in the form of a long belt, and pressed by the plate cylinder 60 and the impression cylinder 62. Is done. On the peripheral surface of the plate cylinder 60, a specular plate 61 (metal plate or resin plate) having a surface with a surface roughness (Ra) of 0.1 μm or less is placed, and the impression cylinder on which the specular plate 61 is heated. 62 is pressed at a constant pressure. The mirror surface of the mirror surface plate 61, that is, the surface having a surface roughness (Ra) of 0.1 μm or less is replicated on the surface of the coating film of the mirror surface layer forming composition, peeled off from the mirror surface plate 61, and immediately subjected to UV irradiation equipment or the like. The light irradiation device 63 is irradiated with light such as ultraviolet rays, and the mirror surface layer 20 having a surface with a surface roughness (Ra) of 0.1 μm or less is cured. Then, it is wound up on a winding device. Details are disclosed in Japanese Patent Publication No. 6-85103, Japanese Patent Publication No. 6-85104, Japanese Patent Publication No. 7-104600, and the like.

(Glossy metallic layer)
The metallic luster layer provided by coating is usually a metallic powder that imparts metallic luster, and if necessary, a coating liquid for forming a metallic luster layer in which a binder is dispersed or dissolved in a solvent. Obtained by coating on an undercoat layer having The metallic luster layer provided by coating can be determined from, for example, the fact that the metal powder is observed in the form of particles rather than a layer by an optical microscope.

The metal powder imparting the metallic luster can be appropriately selected and used depending on the required metallic luster feeling and the function required as necessary. Examples of the metal species of the metal powder include metals such as aluminum, zinc, tin, chromium, nickel, gold, and silver, and alloys such as stainless steel and brass.

  In the present invention, scale metal powder and / or metal nanocolloid particles are preferably used as the metal powder from the viewpoint of obtaining a high metallic luster feeling in combination with the high surface smoothness of the underlayer. .

  When scaly metal powder is used as the metal powder, there is a tendency that the scaly metal powder is arranged in parallel on the coating film of the metallic luster layer, and a continuous metal film is formed. It is possible to increase the nature. The scaly metal powder has a thickness of about 1 to 5 μm and an average diameter of about 10 to 50 μm.

In particular, the scaly metal powder is preferably a scaly aluminum powder from the viewpoint of high metallic luster, concealability, production stability, and productivity. Among the scaly aluminum powders, a scaly aluminum powder produced by the method described below is preferable.
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 scaly aluminum powder produced as described above has a thickness of about 1 to 5 μm, an average diameter of about 10 to 50 μm, and is scaly.

On the other hand, when metal nanocolloid is used as the metal powder, it is possible to improve the metallic luster and obtain the same luminance as the metal vapor deposition layer.
The average particle diameter of the metal nanocolloid particles is preferably 0.1 nm or more from the viewpoint of the high metallic luster of the printed material. On the other hand, 50 nm or less is preferable from the viewpoint of manufacturability. Here, the average particle diameter is a volume average particle diameter by a light scattering method.

  In addition, the metal nanocolloid particles preferably have a particle size distribution close to monodispersion from the viewpoint of the high metallic gloss of the printed material. Specifically, the standard deviation of the particle size is 20% or less of the average particle size. Preferably, it is 15% or less, more preferably 10% or less.

  Specifically, the standard deviation of the particle diameter is preferably 10 nm or less, more preferably 7 nm or less, and further preferably 5 nm or less. Moreover, 0.01 nm or more is preferable, 0.05 nm or more is more preferable, and 0.1 nm or more is still more preferable from the reason of the manufacturability and handling property of metal nanocolloid particles.

  The structure of the metal nanocolloid particles may be a metal nanocolloid particle containing one kind of metal, or a metal nanocolloid particle containing two or more kinds of metals. Examples of metal nanocolloid particles containing two or more kinds of metal include those in which two or more kinds of metals form a core-shell structure, those in which two or more kinds of metals form a cluster, and two or more kinds of metals. Can form an alloy.

For metal nanocolloid particles, an appropriate surfactant is usually selected from anionic surfactants, cationic surfactants, amphoteric surfactants and nonionic surfactants so as to form a stable colloid. Used in combination. Surfactant adsorbs to the generated metal nanocolloid fine particles and prevents sedimentation of the metal nanocolloid fine particles. However, when a surfactant with a charge opposite to metal ions is used, Since metal ions are taken in, the particle diameter of the resulting metal nanocolloid fine particles can be controlled.
The metal nanocolloid particles containing one kind of metal can be produced, for example, by preparing an aqueous solution of a metal salt in the presence of a surfactant, adding a reducing agent to the metal salt, and reducing metal ions to metal.

  In the metallic luster layer provided by the application of the present invention, a binder is usually used in order to hold the metallic powder imparting metallic luster. The binder is preferably composed mainly of a resin. Specifically, as the resin, a cellulose resin, a melamine resin, a polyester resin, a polyamide resin, a polyolefin resin, an acrylic resin, a styrene resin, Examples thereof include thermoplastic elastomers such as ethylene-vinyl acetate copolymer and styrene-butadiene rubber. In particular, those having a relatively low softening point used as a heat-sensitive adhesive, for example, a softening point of 50 to 150 ° C. are preferable. Among the resins used as the binder, cellulose resins, melamine resins, and acrylic resins are preferably used particularly in terms of transferability, scratch resistance, heat resistance, and the like.

  The metallic luster layer provided by the application of the present invention is obtained by adding a metal powder imparting a metallic luster feeling and a colorant such as various dyes or pigments as necessary to the solid content of the entire metallic luster layer. It is preferable to use a coating solution for forming a metallic luster layer prepared by mixing 90 to 20% by weight and 80 to 10% by weight of a binder and dispersing or dissolving in a solvent. When the metal powder and the colorant are less than the above ranges, the coating amount has to be increased in order to obtain the printing density, and the printing sensitivity is insufficient. Moreover, when there are more metal powder and a coloring agent than said range, film formability is not acquired and it becomes a cause of the abrasion resistance fall after printing. Among them, it is preferable that the amount of the binder is as small as possible from the viewpoint of achieving a high metallic luster feeling. The solid content of the entire metallic luster layer is preferably 30 to 60% by weight of a metal powder and, if necessary, a colorant and a binder. It is preferable to mix at a ratio of 40 to 70% by weight.

  The solvent used in the coating liquid for forming the metallic luster layer may be appropriately selected and used depending on the metal powder used and other components. For example, fats such as mineral spirits, hexane, heptane, cyclohexane, and octane. Aromatic hydrocarbons such as aromatic hydrocarbons, benzene, toluene, xylene, halogenated hydrocarbons such as chlorobenzene, trichlorobenzene, perchlorethylene, trichloroethylene, alcohols such as methanol, ethanol, n-propyl alcohol, n-butanol , Ketones such as n-propanone, 2-butanone and methyl ethyl ketone, esters such as ethyl acetate and propyl acetate, ethers such as tetrahydrofuran, diethyl ether and ethyl propyl ether, and other turpentine oils.

The metallic luster layer provided by the coating of the present invention comprises various additives such as a metal powder and, if necessary, a colorant, other dispersant, antistatic agent, a binder component, and a solvent component such as an organic solvent. The coating liquid for forming the metallic luster layer whose composition has been adjusted is 0.1 to 5 g / m ² in thickness in a dry state, preferably by a coating method such as gravure direct coating, gravure reverse coating, knife coating, air coating, roll coating, etc. It is preferable to form such that 0.3 to 1.5 g / m ² is provided. Especially, it is preferable to use a gravure reverse coat as a coating method from the point which is easy to form the coating film excellent in surface smoothness. When the dry coating thickness is less than 0.1 g / m ² , it is difficult to obtain a uniform coating film due to film formation problems, and when the thickness exceeds 5 g / m ² , printing transfer is difficult. In some cases, high energy is required and printing is possible only with a special thermal transfer printer.

(Adhesive layer)
The adhesive layer 30 located on the outermost surface of the thermal transfer sheet of the present invention can be applied with a heat-bonding adhesive that is melted or softened by heat to bond, for example, ionomer resin, acid-modified polyolefin resin, ethylene- (meth) acrylic. Includes acid copolymer, ethylene- (meth) acrylic acid ester copolymer, polyester resin, polyamide resin, vinyl chloride resin, vinyl acetate resin, vinyl chloride-vinyl acetate copolymer, acrylic ester resin Acrylic / methacrylic (meth) acrylic resins, maleic acid resins, butyral resins, alkyd resins, polyethylene oxide resins, phenolic resins, urea resins, melamine resins, melamine-alkyd resins, cellulose resins, polyurethane resins Resin, polyvinyl ether resin, silicone resin, rubber resin, etc. are suitable Can, these resins are 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, and vinyl chloride-vinyl acetate copolymers are preferable in terms of adhesive strength.

  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 When the wax and the thermoplastic resin are contained as fine particles, it is preferable that the average particle size of the wax fine particles and the thermoplastic resin fine particles is 10 μm or less. When the average particle diameter exceeds 10 μm, not only the printing sensitivity is lowered, but also the foil durability of the adhesive layer is remarkably lowered.

The adhesive layer 30 is formed by applying and drying a composition (ink) obtained by dispersing or dissolving the above-mentioned heat-adhesive resin in a solvent by a known coating method or printing method. As the coating method or the printing method, a method similar to the method described in the mirror layer can be applied. Drying may be brushed as necessary to improve transferability. The thickness of the adhesive layer is usually about 0.05 to 10 μm, preferably 0.1 to 5 μm. The dry coating amount is usually about 0.05 to 10 g / m ² , preferably 0.1 to 5 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.

(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.

In the thermal transfer sheet having the metallic luster of the present invention configured as described above, the metallic gloss layer excellent in smoothness is printed on the transfer object, and the smoothness of the metallic gloss layer of the printed matter is maintained. A high metallic luster can be obtained, and a high-quality design can be imparted. According to the thermal transfer sheet having a metallic luster of the present invention, it is possible to obtain a printed matter having a high metallic luster feeling following the three-dimensional structure.
The thermal transfer sheet having a metallic luster of the present invention is most suitable for a thermal printer using a thermal head, but can also be used for molding such as roll thermal transfer, transfer foil of a hot stamping method, and in-mold molding. In addition, since the resolution is excellent, it is suitable for printing images such as characters and designs as a collection of minute patterns, and metallic gloss can be imparted to these images. Accordingly, as a density gradation expression method, if the density gradation is expressed by the size of the transferred portion due to the size of the halftone dots, that is, if the area gradation is used, an intermediate density can be reproduced. In addition to the halftone dots, a screen pattern known in the printing field using a grain or a brick pattern can be used as the area gradation method. In particular, the inclusion of wax or a thermoplastic resin component used in the adhesive layer as fine particles is optimal for recording of area gradations that require high resolution.

  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.

[Evaluation methods]
(1) Surface roughness (Ra) of the surface of the metallic luster layer side of the underlayer
The average surface roughness (Ra) was measured with the following measuring instrument in accordance with JIS B0601.
Measuring instrument: manufactured by Tokyo Seimitsu, surface roughness profile measuring machine Surfcom 1400

(2) Metallic gloss of printed materials (reflectance measurement)
Using the thermal transfer sheets of Examples and Comparative Examples, using a polycarbonate sheet as the transfer target, and using a 600 dpi line type head manufactured by Kyocera Corporation as the thermal head, solid printing was performed under the following conditions. It was.
<Printing conditions>
Thermal head resistance value: 3000Ω
Applied voltage: 18V
Line speed: 1msec / line
About the obtained printed matter, Topcon color chromaticity meter BM-7 was used, and the intensity | strength of the light returned when the HOYA SHOTTT xenon light source was used as a light source was measured.
Example 1
On one side of a 4.5 μm thick polyethylene terephthalate (PET) film, an undercoat layer coating solution having the following composition was applied by gravure coating and dried to a dry coating amount of 0.5 g / m ^2. An undercoat layer having a peeling function was formed. The surface roughness (Ra) of the obtained undercoat layer having a peeling function was 0.02 μm. The following heat-resistant slipping layer coating solution was applied to the other surface of the base material in advance so that it would be 0.3 g / m ² when dried, and then heat-treated at 60 ° C. for 5 days. A heat-resistant slip layer was formed.

<Coating liquid for undercoat layer>
Acrylic resin (BR-87, manufactured by Mitsubishi Rayon Co., Ltd.) 29 parts Polyester resin (Byron 200, manufactured by Toyobo Co., Ltd.) 1 part Toluene / methyl ethyl ketone (weight ratio 1/1) 70 parts

<Coating fluid for heat resistant slipping 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

Next, on the undercoat layer having a peeling function, a metallic gloss layer coating liquid having the following composition is applied by gravure coating to a dry coating amount of 0.3 g / m ² and dried to form a metallic gloss layer. Formed. Further, an adhesive layer having a thickness of 0.5 g / m ² was applied and formed on the metallic luster layer with the following coating solution to obtain a thermal transfer sheet of Example 1 of the present invention.

<Coating liquid for metallic luster layer>
Scale-like aluminum powder (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 subdivided) 4 parts Acrylic resin ( Mitsubishi Rayon Co., Ltd. Product name: BR75) 6 parts Toluene / methyl ethyl ketone (weight ratio 1/1) 90 parts

<Coating liquid for adhesive layer>
Acrylic resin (Mitsubishi Rayon Co., Ltd., trade name: BR87) 25 parts Vinyl chloride-vinyl acetate copolymer (Nissin Chemical Industry Co., Ltd., trade name: Solbin-C) 5 parts Toluene / methyl ethyl ketone (weight ratio 1 / 1) 70 parts

FIG. 4 shows the result of metallic gloss (reflectance measurement) of the printed material for the obtained thermal transfer sheet. FIG. 5 is a partially enlarged view of FIG. In the printed matter of the thermal transfer sheet of Example 1, a sharp peak was obtained in the regular reflection direction (−20 °), indicating that the surface of the printed matter was close to a mirror surface and high metallic gloss was obtained.
Further, when a printed product was formed on the three-dimensional structure using the obtained thermal transfer sheet, the followability of the three-dimensional structure was good.

(Example 2)
On one side of a 4.5 μm thick polyethylene terephthalate (PET) film, the undercoat coating liquid used in Example 1 was applied by gravure coating so that the dry coating amount was 0.25 g / m ² and dried. Thus, a release layer was formed. Thereafter, a mirror layer coating solution having the following composition was applied by gravure coating so that the coating amount after drying was 0.5 g / m ² , dried and cured at 50 ° C. for 24 hours to form a mirror layer. . The surface roughness (Ra) of the obtained mirror surface layer was 0.02 μm. A heat resistant slipping layer was formed on the other surface of the PET film in the same manner as in Example 1.

<Coating liquid for mirror layer>
Acrylic polyol 3 parts Curing agent (isocyanate) 1 part Toluene / methyl ethyl ketone (weight ratio 1/1) 9 parts

Next, on the mirror surface layer, a metallic gloss layer coating liquid having the same composition as in Example 1 is applied by gravure coating to a dry coating amount of 0.3 g / m ² and dried to form a metallic gloss layer. did. Further, an adhesive layer was formed on the metallic gloss layer in the same manner as in Example 1 to obtain a thermal transfer sheet of Example 2 of the present invention.

FIG. 4 shows the result of metallic gloss (reflectance measurement) of the printed material for the obtained thermal transfer sheet. FIG. 5 is a partially enlarged view of FIG. In the printed matter of the thermal transfer sheet of Example 2, a sharp peak was obtained in the regular reflection direction (−20 °), indicating that the surface of the printed matter was close to a mirror surface and a high metallic gloss was obtained.
Further, when a printed product was formed on the three-dimensional structure using the obtained thermal transfer sheet, the followability of the three-dimensional structure was good.

(Example 3)
A polyethylene terephthalate film (trade name: Lumirror, manufactured by Toray Industries, Inc.) having a thickness of 6 μm was used as a substrate, and a heat-resistant slipping layer was formed on the back surface of the substrate in the same manner as in Example 1. The undercoating liquid used in Example 1 is applied to the surface of the base material provided with the heat-resistant slipping layer without the heat-resistant slipping layer by gravure coating, so that the dry coating amount is 0.25 g / m. ^The release layer was formed by coating and drying to be ² .

On the release layer, the mirror surface coating solution prepared as described below is such that the film speed is 50 m / min and the thickness after drying is 0.5 to 1.0 g / m ² . It was coated with a gravure reverse coater and dried at 100 ° C. to form a mirror surface forming layer.

<Preparation of coating liquid for mirror surface layer>
(1) Preparation of urethane-modified acrylate resin solution A 2-liter four-necked flask equipped with a condenser, a dropping funnel and a thermometer was charged with 40 g of toluene and 40 g of methyl ethyl ketone (MEK) together with an azo-based initiator. A mixed liquid of 22.4 g of ethyl methacrylate (HEMA), 70.0 g of methyl methacrylate (MMA), 20 g of toluene, and 20 g of MEK was added dropwise through a dropping funnel over about 2 hours at a temperature of 100 to 110 ° C. for 8 hours. After reacting, it was cooled to room temperature. A mixed liquid of 27.8 g of 2-isocyanatoethyl methacrylate (manufactured by Showa Denko, Karenz MOI), 20 g of toluene and 20 g of MEK was added thereto, and an addition reaction was carried out using dibutyltin laurate as a catalyst. The reaction product was subjected to IR analysis to confirm the disappearance of the absorption peak at 2200 cm ⁻¹ of the isocyanate group, and the reaction was completed. The urethane-modified acrylate resin solution obtained above has a non-volatile content of 41.0% and a viscosity of 130 mPa (30 ° C.), and the molecular weight in terms of standard polystyrene measured by GPC (solvent: THF) of the resin is 3. The average number of double bonds in one molecule of the polymer was 13.8 mol%, and the acid value was 0 (mgKOH / g).

(2) Preparation of photocurable resin composition The following photocurable resin composition was prepared using the resin solution obtained above.
100 parts Amino-modified reactive silicone oil (KF-860, manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part Polyfunctional monomer (NK Oligo U-15HA, manufactured by Shin-Nakamura Chemical Co., Ltd.) 10 parts Urethane acrylate (purple light UV-3200B manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 10 parts Photosensitizer (Irgacure 907 manufactured by Ciba Japan Co., Ltd.) 5 parts
The above was diluted with methyl ethyl ketone to prepare a composition having a solid content of 50%.

Next, using a device as shown in FIG. 3, a mirror plate was stamped onto the surface of the mirror surface forming layer to duplicate the mirror surface. A mirror plate (surface roughness is 0.001 μm or less) duplicated by the 2P method using an ultraviolet curable resin as a base plate with a glass having a high specularity is attached to a plate cylinder (embossing roller) of a duplication device, The mirror surface forming layer was heated and pressed between the plate cylinder and the pressure cylinder facing the plate cylinder, and the mirror surface was replicated on the mirror surface forming layer. After replication, the mirror surface forming layer was immediately irradiated with ultraviolet rays and cured to obtain a mirror surface layer. The surface roughness (Ra) of the obtained mirror surface layer was 0.01 μm. Next, on the mirror surface layer, a metallic gloss layer coating liquid having the same composition as in Example 1 is applied by gravure coating to a dry coating amount of 0.3 g / m ² and dried to form a metallic gloss layer. did. Further, an adhesive layer having a thickness of 0.5 g / m ² was applied and formed on the metal layer with the same adhesive layer coating solution as in Example 1 to obtain a thermal transfer sheet of Example 3 of the present invention.

FIG. 4 shows the result of metallic gloss (reflectance measurement) of the printed material for the obtained thermal transfer sheet. FIG. 5 is a partially enlarged view of FIG. The printed matter of the thermal transfer sheet of Example 3 has a sharper peak in the specular reflection direction (−20 °) than the thermal transfer sheets of Example 1 and Example 2, and the surface of the printed matter approaches a mirror surface and has a high metallic luster. It was shown that a feeling was obtained.
Further, when a printed product was formed on the three-dimensional structure using the obtained thermal transfer sheet, the followability of the three-dimensional structure was good.

(Comparative Example 1)
In the thermal transfer sheet produced in Example 1, the same undercoat layer coating solution as in Example 1 was coated on one side of a polyethylene terephthalate (PET) film having a thickness of 4.5 μm as an underlayer by gravure coating, and the dry coating amount Was applied and dried so as to be 0.21 g / m ² to form an undercoat layer having a peeling function. The surface roughness (Ra) of the obtained undercoat layer having a peeling function was 0.5 μm. A thermal transfer sheet of Comparative Example 1 was obtained in the same manner as Example 1 except for the undercoat layer.
FIG. 4 shows the result of metallic gloss (reflectance measurement) of the printed material for the obtained thermal transfer sheet. FIG. 5 is a partially enlarged view of FIG. 4 and 5, the printed matter of the thermal transfer sheet of Comparative Example 1 has a lower peak in the regular reflection direction (−20 °) than the printed matter of the thermal transfer sheets of Examples 1 to 3, and −30 It was revealed that there was a lot of light scattered in directions other than the regular reflection direction such as ° to -45 °. The surface of the printed material of the thermal transfer sheet of Comparative Example 1 had a low metallic gloss even visually.

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 which shows the method of forming the mirror surface layer of the thermal transfer sheet of this invention. It is a figure which shows the reflectance of the printed matter of the thermal transfer sheet of Examples 1, 2, and 3 and the comparative example 1. FIG. FIG. 3 is a partially enlarged view showing the reflectance of a printed matter of thermal transfer sheets of Examples 1, 2, and 3 and Comparative Example 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base material 10 Undercoat layer 11 Release layer 12 Mirror surface layer 15 Metal gloss layer side surface 20 Metal gloss layer 30 Adhesion layer 40 Heat-resistant slip layer 60 Plate cylinder 61 Mirror plate 62 Pressure drum 63 Light irradiation apparatus 100 Mirror surface formation sheet

Claims (6)

  On one surface of the film substrate, at least an undercoat layer having a peeling function, a metallic gloss layer provided by coating, and an adhesive layer are sequentially provided, and the surface roughness of the undercoat layer on the metal gloss layer side surface ( A thermal transfer sheet in which Ra) is 0.1 μm or less.   The thermal transfer sheet according to claim 1, wherein the metallic luster layer provided by the coating contains scaly metal powder and / or metal nanocolloid particles.   The thermal transfer sheet according to claim 1 or 2, wherein the undercoat layer contains a thermosetting resin and / or a photocurable resin.   The undercoat layer is composed of two or more layers, and includes at least a release layer on the film substrate side, and a mirror surface layer containing a thermosetting resin and / or a photocurable resin on the metallic luster layer side and having the surface roughness. The thermal transfer sheet according to any one of claims 1 to 3.   The thermal transfer sheet according to claim 4, wherein the mirror surface layer has a softening point of 130 ° C. or higher.   6. The thermal transfer sheet according to claim 1, wherein the surface of the undercoat layer on the metallic luster layer side is formed by pressing with a surface having a surface roughness (Ra) of 0.1 μm or less.

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