JP2012035448A - Protective layer thermal transfer sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protective layer thermal transfer sheet which enables formation of a protective layer where rainbow-like dispersions are eliminated and glossiness is increased without losing characteristics as a protective layer.SOLUTION: The protective layer thermal transfer sheet includes: a base film and a thermally transferable protective layer formed on at least one side or a part of the base film. A peeling layer formed on the interface of the base film side of the protective layer is a resin composition containing both acrylic resin and styrene acrylic resin. Characteristically, the acrylic resin is contained at 30 to 60 wt.% and the styrene acrylic resin is contained at 40 to 70 wt.%, respectively, against the whole amount of the resin composition.

Description

  The present invention relates to a thermal transfer sheet used in a thermal transfer type thermal printer, and more particularly to a protective layer thermal transfer sheet for forming a protective layer on the surface of a printed image.

  2. Description of the Related Art In recent years, a technique for easily and quickly forming an image of a gradation image, a color image, a character, and the like by a thermal transfer method has become widespread. Such thermal transfer systems can be broadly classified into a thermal sublimation transfer system and a thermal melt transfer system.

  Of these, in the thermal sublimation transfer method, a thermal transfer sheet is used in which a dye layer in which a sublimable dye used as a coloring material is dissolved or dispersed in a binder resin is supported on a base material, and this thermal transfer sheet is superposed on an image receiving film for thermal transfer. By applying energy according to image information to a heating device such as a head, the sublimation dye contained in the dye layer on the thermal transfer sheet is transferred to the image receiving sheet to form an image.

  Such a heat-sensitive sublimation transfer method can control the amount of dye transfer in dot units according to the amount of energy applied to the thermal transfer sheet, so that it is excellent in forming a gradation image, and the formation of characters, symbols, etc. is simple and quick. It has the advantage of being.

  Images formed by the above-described thermal sublimation transfer method protect the images because the transferred dye is present on the surface of the transfer target, and from the viewpoint of image protection such as light resistance and wear resistance. In addition, a protective layer is formed on the image surface, and many proposals have been made on techniques for that purpose (see, for example, Patent Document 1 and Patent Document 2).

  As a characteristic of the protective layer formed on the surface of the printed image, in addition to the originally required performance of protecting the image, it is required to eliminate “rainbow unevenness” from the viewpoint of further improving the image quality. It has become. “Rainbow unevenness” in this case is a phenomenon that is noticeable when observing a printed material with a dark background color, and is a phenomenon in which rainbow-colored stripes are seen in the flow direction of printing. From the viewpoint of print quality of printed matter, it is required that such rainbow unevenness is not visually observed (Patent Document 3).

  In general, it is known that the rainbow unevenness increases when trying to improve the glossiness of the image surface.Therefore, the reduction of rainbow unevenness and the improvement of the glossiness are mutually contradictory properties. It was difficult to eliminate.

JP 2000-80844 A JP 2000-71626 A JP 2006-228772 A

  The present invention has been made in view of the above circumstances, and it is possible to form a protective layer capable of forming a protective layer in which both rainbow unevenness is eliminated and glossiness is improved without impairing the properties as the protective layer. An object is to provide a thermal transfer sheet.

  In order to solve the above-described problems, a protective layer thermal transfer sheet according to the present invention includes a base film and a protective layer formed on at least a part of one surface of the base film so as to be capable of thermal transfer. A protective layer thermal transfer sheet, wherein the release layer formed at the interface of the protective layer on the base film side is a resin composition comprising an acrylic resin and a styrene acrylic resin in combination. The acrylic resin is contained in an amount of 30 to 60% by weight and styrene acrylic resin in an amount of 40 to 70% by weight based on the total amount of the composition.

  Furthermore, in this invention, Preferably, the said protective layer is formed in the order of a peeling layer, a primer layer, and a heat seal layer from the said base film side.

  Furthermore, in the preferable aspect of this invention, the thickness of the said peeling layer is 0.1 micrometer-10 micrometers, More preferably, it is 0.5 micrometer-5 micrometers.

  Moreover, in this invention, the aspect formed by the dye layer being formed on the same surface as the surface in which the said protective layer of the said base film was formed is included.

  Moreover, in the other preferable aspect of this invention, a back surface slipping layer is formed in the surface on the opposite side to the surface in which the said protective layer of the said base film was formed.

  The present invention further includes a printed product obtained by transferring the protective layer of the protective layer thermal transfer sheet.

  As can be understood from the results of the following examples and comparative examples, according to the present invention, a protective layer in which both the elimination of rainbow unevenness and the improvement of glossiness are achieved without impairing the properties as the protective layer. A protective layer thermal transfer sheet that can be formed can be provided.

Sectional drawing of the protective layer thermal transfer sheet which concerns on one embodiment of this invention. Sectional drawing of the protective layer thermal transfer sheet which concerns on one embodiment of this invention.

  FIG. 1 shows a schematic cross-sectional view of one embodiment of the protective layer thermal transfer sheet according to the present invention. In the figure, the protective layer thermal transfer sheet 1 has a release layer 3, a primer layer 4, and a heat seal layer 5 formed in this order on one surface of a substrate sheet 2. In the case of the configuration shown in FIG. 1, the protective layer has a three-layer configuration of a release layer, a primer layer, and a heat seal layer.

As the base sheet 1, the same base sheet as widely used in this field can be used as appropriate, and is not particularly limited. Specific examples of the base sheet include polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyphenylene sulfide, polyether ketone, polyether sulfone and other highly heat-resistant polyesters; polypropylene, polycarbonate, cellulose acetate, polyethylene derivatives, Examples thereof include plastic films such as polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, polyimide, polymethylpentene, and ionomer, and laminates thereof. The plastic film may be stretched or unstretched. Although the thickness of a base material sheet can be suitably selected in consideration of strength, heat resistance and the like, it is usually about 1 to 100 μm.

Release layer In the present invention, in order to solve the above technical problem, it is important that the composition of the binder resin of the release layer is set to a specific blending ratio of the acrylic resin and the styrene acrylic resin. Hereinafter, this point will be described.

  As described above, in the protective layer thermal transfer sheet according to the present invention, the release layer is a resin composition comprising an acrylic resin and a styrene acrylic resin in combination, and is based on the total amount of the resin composition. The acrylic resin is contained in the range of 30 to 60% by weight and the styrene acrylic resin in the range of 40 to 70% by weight.

  The acrylic resin used in the present invention is a polymer of acrylic acid, methacrylic acid, acrylic ester or methacrylic ester, and polymethyl methacrylate resin (PMMA) can be preferably used. PMMA having a weight average molecular weight of 60,000 to 80,000 can be preferably used.

  On the other hand, in the present invention, the styrene acrylic resin means copolymerization of an acrylic acid monomer and a styrene monomer. As the acrylic acid monomer, for example, acrylic acid, methacrylic acid, acrylic ester or methacrylic ester is preferably used. I can do things. As the styrene monomer, any of styrene having a substituent and styrene having no substituent can be preferably used.

  Furthermore, a styrene acrylic resin having a weight average molecular weight of 60,000 to 70,000 can be preferably used.

  In the present invention, it is important to limit the blending ratio of the acrylic resin and the styrene acrylic resin to a range of 3: 7 to 6: 4. When the blending ratio is out of this range, it becomes difficult to harmoniously realize both characteristics of reducing rainbow unevenness and improving glossiness. Further, if it is out of this range, the scratch resistance is lowered and it becomes difficult to use it as a protective layer thermal transfer sheet. Further, according to the knowledge of the present inventor, when the blending ratio of the acrylic resin is increased, the glossiness tends to decrease, and conversely, when the ratio of the styrene acrylic resin is increased, the scratch resistance tends to be decreased.

  In this invention, the peeling layer may contain the wax with the binder resin mentioned above. When the wax is contained, the scratch resistance and foil breakability of the release layer are improved.

  Examples of the wax include polyethylene wax, polyester wax, polystyrene powder, olefin powder, microcrystalline wax, carnauba wax, paraffin wax, Fischer-Tropsch wax, various low molecular weight polyethylene, wood wax, beeswax, whale wax, wool wax, Examples include shellac wax, candelilla wax, petrolactam, partially modified wax, fatty acid ester, and fatty acid amide.

  The wax component is usually contained in the release layer in an amount of about 0.1 to 30% by weight, preferably about 0.1 to 10% by weight.

  In the present invention, the release layer may further contain an ultraviolet absorber. By blending the ultraviolet absorber, it is possible to improve the light resistance and weather resistance of the image of the transferred material covered with the protective layer after being transferred.

  As the ultraviolet absorber, conventionally known organic ultraviolet absorbers such as salicylate, benzophenone, benzotriazole, substituted acrylonitrile, nickel chelate, hindered amine and the like can be widely used. Also, for example, addition polymerizable double bonds such as vinyl groups, acryloyl groups, and methacryloyl groups, or functional groups such as alcoholic hydroxyl groups, amino groups, carboxyl groups, epoxy groups, and isocyanate groups are introduced into these ultraviolet absorbers. An ultraviolet absorbing resin may be contained in the release layer.

  Furthermore, you may contain various additives, such as antioxidant and a fluorescent whitening agent, in the said peeling layer. The release layer is a gravure printing method, a screen printing method, which is obtained by adding a necessary additive such as wax to the binder resin and dissolving or dispersing in water, an organic solvent or the like on the binder resin. It is formed by applying and drying according to a normal coating method such as a reverse roll coating method using a gravure plate.

  The thickness of the release layer is usually about 0.1 to 10 μm, preferably about 0.5 to 5 μm.

  In particular, in the present invention, since it has the above composition, it is unexpected that rainbow unevenness does not occur even if the thickness of the release layer is 1.0 μm or less, for example.

  That is, according to the knowledge of the present invention, when an acrylic resin alone is used as a release layer, a phenomenon in which rainbow unevenness occurs at a thickness of about 1.0 μm or less is used. In this case, it is unexpected that the rainbow unevenness does not occur even in the thickness range of 0.5 to 1.0 μm.

  In the present invention, both the improvement of glossiness and the prevention of rainbow unevenness can be realized by including the resin composition as described above in the structure of the release layer.

  The reason why such an unexpected effect occurs is not necessarily clear, and the present invention is not bound by any theory, but the optical characteristics at the interface of the constituent layers of the protective layer thermal transfer sheet contribute well. Therefore, it is presumed that the cause of rainbow unevenness is suppressed.

Release layer In this invention, you may provide a release layer further between the peeling layer 3 and the base material sheet 2 as needed. When the peelability between the base sheet and the protective layer is not appropriate, the release layer can be provided in order to adjust the adhesiveness between the base sheet and the protective layer and to peel the protective layer satisfactorily. Such release layers include, for example, various waxes such as silicone wax, silicone resin, fluororesin, acrylic resin, water-soluble resin, cellulose derivative resin, urethane resin, acetic acid vinyl resin, acrylic vinyl ether resin, anhydrous It is composed of various resins such as maleic resin and mixtures thereof.

  The release layer is formed by applying a coating solution containing at least one selected from the group consisting of the above waxes and the above resin onto a base sheet according to a conventionally known coating method and drying it. Can do. The thickness of the release layer is usually about 0.5 to 5.0 μm.

  When the release layer is provided, it is desirable that the thermal transfer resin layer is peeled off from the release layer by transfer, and the release layer itself is formed so as to remain on the substrate sheet side.

Primer Layer In the protective layer thermal transfer sheet of the present invention, the primer layer 4 can be formed between the release layer 3 and the heat seal layer 5. This primer layer is also called a dye primer layer and has a function of adhering the dye layer and the base film. Further, since the primer layer contains fine particles, it may have a function of irregularly reflecting light transmitted through the release layer, suppressing reflection at the heat seal layer / release layer interface, and reducing rainbow unevenness.

  In the present invention, in the thermal transfer sheet having the configuration as shown in FIG. 1, the primer layer can be formed of fine particles having an average primary particle size in the range of 10 to 100 nm.

  Such fine particles may be either inorganic fine particles or organic fine particles as long as they are colorless or white. From the viewpoint of particle hardness and heat resistance, inorganic fine particles are preferred. In the present invention, the term “colorless or white” means that transparency is not impaired when provided as a coating film. Use of fine particles that are not colorless or white is not preferable because the coating film is colored and the image is colored like a background fog.

  Silica, alumina, titania, calcium carbonate, etc. can be used as the inorganic fine particles. Silica and alumina are preferably used. As the organic fine particles, styrene fine particles, acrylic fine particles, melamine resin fine particles and the like having a heat resistant temperature of 80 ° C. or higher, preferably 120 ° C. or higher are used. When organic fine particles having a heat-resistant temperature lower than 80 ° C. are used, the particles are deformed by heat and pressure during printing, and there is a problem that irregularities at the original interface cannot be maintained. The heat-resistant temperature of the particle is the maximum temperature that the particle can withstand without being broken or crushed by heat. In the present invention, the heat-resistant temperature is measured by a thermal stress strain measuring device (TMA) (manufactured by Seiko Electronics Co., Ltd.). ing. However, as long as it can be measured by the same principle and method, it can be measured without being limited to the left device.

  Fine particles having an average primary particle size of 8 to 100 nm, preferably 8 to 80 nm, more preferably 10 to 70 nm are used. If the average primary particle size is too small, the effect of preventing rainbow unevenness cannot be seen. On the other hand, if it is too large, the transparency of the protective layer is impaired. In the present invention, the “average primary particle size” is a value measured by the BET method.

  In addition to the primer layer, additives such as leveling agents, antifoaming agents, fluorescent whitening agents, UV absorbers, etc. are added in an amount of about 0.01 to 5% by weight based on the total weight of the primer layer. May be.

The primer layer is formed by applying a coating solution prepared by dissolving or dispersing fine particles and, if necessary, other additives in a solvent such as an organic solvent or water, on the release layer by a known coating method such as a wire coating method. It is formed by drying. The thickness of the primer layer is about 0.03 to 1 g / m ² , preferably about 0.03 to 0.5 g / m ² . If the primer layer is too thick, transparency will be impaired, and if it is too thin, the effect of preventing rainbow unevenness will not be seen.

  When the primer layer comprising fine particles is observed after production, it is observed as being contained in the resin constituting the heat seal layer described below, and is not observed independently as a fine particle layer. In the present invention, for the sake of convenience, a group of fine particles formed by applying and drying fine particles on the layer previously formed in the production process, in the structure of FIG. 1, on the release layer is called a primer layer.

Heat Seal Layer The heat seal layer 5 plays a role of adhesion of the protective layer to the image surface. As the resin constituting the heat seal layer, any resin containing conventionally known pressure-sensitive adhesives, heat-sensitive adhesives and the like can be used, but a glass transition temperature (Tg) of 50 to 80 ° C. is a thermoplastic resin. Is preferred. Specific examples of such thermoplastic resins include polyester resins, vinyl chloride-vinyl acetate copolymer resins, acrylic resins, butyral resins, epoxy resins, polyamide resins, vinyl chloride resins, and the like. The heat seal layer may contain additives such as an ultraviolet absorber, an antioxidant, and a fluorescent brightening agent.

  The heat seal layer is formed by applying a coating solution obtained by dissolving or dispersing the above resin and other additives in a solvent such as an organic solvent on the primer layer by a known coating method such as a wire coating method, curing, and drying. Is formed. The thickness of the heat seal layer is usually about 0.1 to 10 μm, preferably about 0.5 to 5 μm.

Other Preferred Configurations The protective layer in the protective layer thermal transfer sheet of the present invention is preferably formed so that the transmittance is 95% or more, preferably 98% or more. When the transmittance is lower than 95%, there arises a problem that the concentration of the dye printed on the base of the protective layer appears to be thin. In this invention, the transmittance | permeability uses the transmittance | permeability in the wavelength range of 500-600 nm with a spectrophotometer.

  In the present invention, an interlayer adhesive layer different from the durable layer, the ultraviolet absorbing layer, and the fine particle layer may be further provided as necessary before forming the heat seal layer.

  In the present invention, a back layer may be formed on the other surface of the base sheet. The back layer is provided for the purpose of preventing thermal fusion between a heating device such as a thermal head and the base sheet 2 and smooth running. Examples of the resin used for the back layer include cellulose resins such as ethyl cellulose, hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, cellulose butyrate, and nitrocellulose; polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl Vinyl resins such as pyrrolidone; Acrylic resins such as polymethyl methacrylate, polyethyl acrylate, polyacrylamide, and acrylonitrile-styrene copolymers; polyamide resins; polyvinyl toluene resins; coumarone indene resins; polyester resins; A simple substance or a mixture of natural or synthetic resins such as silicone-modified or fluorine-modified urethane is used. Of the above resins, a resin having a hydroxyl group reactive group (for example, butyral resin, acetal resin, etc.) is used in order to further increase the heat resistance of the back layer, and polyisocyanate is used in combination as a crosslinking agent. Thus, a crosslinked resin layer is preferable.

  Further, in order to impart slidability with the thermal head, a solid or liquid release agent or lubricant may be added to the back layer to provide heat-resistant lubricity. Examples of release agents or lubricants include various waxes such as polyethylene wax and paraffin wax; higher aliphatic alcohols, organopolysiloxanes, anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants Various surfactants such as an activator and a fluorine-based surfactant; fine particles of inorganic compounds such as organic carboxylic acids and derivatives thereof, fluorine-based resins, silicone-based resins, talc, and silica can be used. The amount of lubricant contained in the back layer is about 5 to 50% by weight, preferably about 10 to 30% by weight in the back surface.

  The back layer is a gravure printing method, a screen printing method, a reverse coating method using a gravure plate, or the like obtained by dissolving or dispersing the above resin and other additives in a solvent such as water or an organic solvent on a base sheet. It is formed by applying and drying according to the usual coating method. The thickness of the back layer is usually about 0.1 to 10 μm, preferably about 0.5 to 5 μm.

  The protective layer thermal transfer sheet of the present invention is not limited to the above-described embodiment, and is a composite type protective layer thermal transfer sheet of a thermal transferable protective layer and a thermal sublimation colorant layer, a thermal transferable protective layer and thermal fusion It can be arbitrarily set according to the purpose of use, such as a composite type protective layer thermal transfer sheet with a colorant material layer.

  In the case of the former composite type protective layer thermal transfer sheet, as long as it has a dye receiving layer as a transfer target, image formation by the thermal transfer method and transfer of the protective layer to the transfer target can be performed simultaneously. .

  As an example of the protective layer heat transfer sheet, at least one color material layer selected from the group consisting of a heat transferable protective layer, a heat sublimation color material layer, and a heat meltable color material layer is provided on one surface of the base sheet. A protective layer thermal transfer sheet and the like that are sequentially provided can be exemplified.

  FIG. 2 is a schematic cross-sectional view showing another example of the protective layer thermal transfer sheet of the present invention. In FIG. 2, the protective layer thermal transfer sheet 21 of the present invention has a heat sublimable color material layer Y, a heat sublimation color material layer M, a heat sublimation color material layer C, a heat sublimation property on one surface of a substrate sheet 22. The color material layer B and the heat transferable protective layer 26 are formed in the surface order, and the back layer 27 is formed on the other surface of the base sheet 22. The heat transferable protective layer 26 includes, for example, a release layer 23, a primer layer 24, and a heat seal layer 25.

  The heat-sublimable color material layers Y, M, C, and B in FIG. 2 may be heat-meltable color material layers Y, M, C, and B, and are configured by mixing these layers. Also good.

  There is no restriction | limiting in particular as a to-be-transferred body which transfers a protective layer using this invention protective layer thermal transfer sheet. The transfer target may be, for example, a sheet made of any base material such as plain paper, high-quality paper, tracing paper, and plastic film. Further, the transfer object may have any shape such as a card, a postcard, a passport, a notepaper, a report sheet, a notebook, a catalog, and the like.

  Specific examples of the transfer object of the present invention include, for example, stock certificates, securities, certificates, passbooks, boarding tickets, car horse tickets, stamps, stamps, appreciation tickets, admission tickets, tickets, etc .; cash cards, credit cards , Prepaid cards, members cards, greeting cards, postcards, business cards, driver's licenses, IC cards, optical cards, etc .; cartons, cases such as containers; bags: forms, envelopes, tags, OHP sheets, slide films , Bookmarks, calendars, posters, brochures, menus, passports, POP supplies, coasters, tisplays, nameplates, keyboards, cosmetics, watches, lighters, and other accessories; stationery, report paper, and other stationery; building materials, panels, emblems, Keys, cloth, clothing, footwear, radio, TV, calculator, OA equipment, etc., each Sample book, mention may be made of the album, the output of computer graphics, the medical image output, and the like.

  The image on the transfer medium may be formed by any method such as an electrophotographic method, an ink jet recording method, or a thermal transfer recording method.

  The heat sublimable color material layer is formed by, for example, supporting a binder resin with a dye that transfers heat mainly by sublimation.

  As the dye, any of the conventionally used dyes used in thermal transfer sheets can be used effectively, and is not particularly limited. Preferable dyes include magenta dyes such as MS Red G, Macrolex Red Violet R, Ceres Red 7B, Samaron Red HBSL, Resolin Red F3BS, and the like. Examples of yellow dyes include Holon Brilliant Yellow 6GL, PTY-52, Macrolex Yellow 6G, and the like. Examples of the cyan dye include Kayaset Blue 714, Waxoline Blue AP-FW, Holon Brilliant Blue S-R, MS Blue 100, and the like.

  Any conventionally known binder resin for supporting the dye can be used. Examples of preferred binder resins include cellulose resins such as ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate and cellulose butyrate; polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl pyrrolidone, Examples thereof include vinyl resins such as polyacrylamide; polyester resins and the like. Of these, cellulose resins, polyvinyl resins such as polyvinyl butyral and polyvinyl acetal, and polyester resins are preferred from the viewpoints of heat resistance, dye transferability, and the like. Furthermore, conventionally well-known various additives may be mix | blended in the heat sublimable color material layer as needed.

  The content of the dye is usually about 5 to 90% by weight, preferably about 10 to 70% by weight, based on the total amount of the heat sublimable color material layer.

  The heat sublimable color material layer is preferably formed by adding the sublimation dye, binder resin and other optional components in an appropriate solvent, and dissolving or dispersing each component to form a heat sublimable color material layer forming paint. Alternatively, it is carried out by preparing an ink, applying it surface-sequentially on the substrate sheet and drying it.

  The thickness of the heat sublimable color material layer is usually about 0.2 to 5 μm, preferably about 0.4 to 2 μm.

  The heat-meltable color material layer is obtained by loading a colorant on a binder.

  As the colorant, among organic or inorganic pigments and dyes, those having good characteristics as a recording material, for example, those having a sufficient color density and not browned by light, heat, temperature or the like are preferable. As such a colorant, for example, those having a hue such as black, cyan, magenta, and yellow are used.

  As the binder, for example, a mixture in which drying oil, resin, mineral oil, cellulose derivatives, rubber derivatives and the like are blended as a main component of the wax is used.

  Examples of the wax include microcrystalline wax, carnauba wax, paraffin wax, Fischer-Tropsch wax, various low molecular weight polyethylene, wood wax, beeswax, whale wax, ibota wax, wool wax, shellac wax, candelilla wax, petrolactam, polyester wax. Various waxes such as partially modified waxes, fatty acid esters, and fatty acid amides are used.

  Further, vinyl chloride / vinyl acetate copolymer resin, acrylic resin, chlorinated rubber, vinyl chloride / vinyl acetate copolymer resin, cellulosic resin, and the like can be used as a bander.

  The formation of the heat-meltable color material layer is carried out by preparing a composition for forming a heat-meltable color material layer to which the colorant, binder resin, and other additives as necessary are added, and applying this to the above base sheet. Further, it is carried out by applying a hot melt coat, a hot lacquer coat, a gravure coat, a gravure reverse coat, a knife coat, an air coat, a roll coat method, and the like, followed by drying. The thickness of the meltable color material layer is usually about 0.1 to 8 μm, preferably about 0.4 to 2 μm. The hot-melt colorant layer formed on the base sheet may consist of one layer, or may consist of two or more layers.

  In the present invention, a primer layer may be provided between the base sheet and the heat sublimable color material layer. Moreover, in this invention, the peeling layer may be provided between the base material sheet and the heat-meltable color material layer. This release layer may be the same as the release layer described above.

  In using the protective layer thermal transfer sheet of the present invention, conventionally known methods of using the protective layer thermal transfer sheet can be employed as they are. For example, the heat seal layer surface of the protective layer thermal transfer sheet of the present invention may be superposed on the transfer target, and the thermal transfer resin layer may be thermally transferred onto the transfer target.

  Hereinafter, the present invention will be described more specifically based on examples of the present invention and comparative examples. In Examples and Comparative Examples, “part” or “%” is based on mass unless otherwise specified.

The products used in this example are briefly summarized below.
Dianal BR-60: Polymethyl methacrylate (PMMA), manufactured by Mitsubishi Rayon Co., Ltd., Mw: 70000
Dianal BR-50: styrene copolymer polymethyl methacrylate (PMMA), manufactured by Mitsubishi Rayon Co., Ltd., Mw: 65000
Byron 700: Polyester, manufactured by Toyobo Co., Ltd., Mn: 9000
Tinuvin 900: UVA compound, UVA manufactured by Ciba Specialty Chemicals Co., Ltd. is an abbreviation of “ULTRA-VIOLET LIGHT ABSORBER”.

Production of protective layer thermal transfer sheet (thermal transfer ribbon) (release layer)
Dialnal BR-60 and BR-50 were mixed at a weight ratio shown in Table 1 below, and 40 parts of toluene and 40 parts of methyl ethyl ketone were added and mixed to prepare a release layer coating composition.

The obtained coating composition was applied to a PET film (base film) having a thickness of 4.5 μm with a wire coater bar (# 5) so that the coating amount was 1.3 g / m ² . The obtained coated film was dried in an oven at 110 ° C. for 1 minute to form a release layer.

(Primer layer)
A coating composition having the following composition was diluted with a primer dilution solvent so that the solid content would be 3% to prepare a primer layer coating composition. The obtained coating composition was applied to a PET film coated with the first layer so as to have the coating amount (0.2 g / m ² ) described in Table 1 using a wire coater bar (# 3). The obtained coated film was dried in an oven at 110 ° C. for 1 minute.

<Primer layer coating solution 1>
Alumina sol (Alumina sol 200, manufactured by Nissan Chemical Industries, Ltd., solid content 10%) 24 parts Polyvinylpyrrolidone resin (K-90, manufactured by ISP) 0.6 part Water 26.9 parts Isopropyl alcohol 48.5 parts <Primer layer coating Engineering fluid 2>
Alumina sol (Alumina sol 200, manufactured by Nissan Chemical Industries, Ltd., solid content 10%) 15 parts Polyvinylpyrrolidone resin (K-90, manufactured by ISP) 1.5 parts Water 35 parts Isopropyl alcohol 48.5 parts

(Heat seal layer (HS) layer)
Byron 700: 23.5 parts, Tinuvin 900: 6 parts, Silicia 310P (manufactured by Fuji Silysia Chemical Co., Ltd.): 0.5 part, Toluene: 35 parts, Methyl ethyl ketone: 35 parts are mixed to prepare an ink for heat seal layer. did. The obtained ink was apply | coated to PET film which apply | coated the 2nd layer so that it might become a coating amount of 1.0 g / m < ² > with a wire coater bar (# 4). The obtained coated film was dried in an oven at 110 ° C. for 1 minute.

Preparation of Thermal Transfer Image Receiving Sheet An adhesive layer forming coating solution having the following composition was applied to one surface of a 39 μm-thick microvoided film of the fine void layer and dried to form an adhesive layer. Next, a support having a back layer provided on one side of a coated paper (186 g / m2) and a microvoid film are bonded to the opposite side of the support on the side having the back layer provided according to the forming conditions described later. Lamination was performed so that the agent layer overlapped.
<Coating liquid for forming the adhesive layer>
Polyfunctional polyol (Takelac A-969V, manufactured by Mitsui Chemicals) 30.0 parts Isocyanate (Takenate A-5, manufactured by Mitsui Chemicals) 10.0 parts Ethyl acetate 60.0 parts

Subsequently, a primer layer forming coating solution having the following composition is applied to the surface opposite to the surface on which the adhesive layer of the microvoid film is provided by wire bar coating so that the dry coating amount becomes 2.0 g / m 2. The primer layer was formed by applying and drying.
<Primer layer forming coating solution>
Polyester polyol (Adcoat, manufactured by Toyo Morton Co., Ltd.) 15.0 parts Methyl ethyl ketone / toluene (mass ratio 2: 1) 85.0 parts

On the formed primer layer, a dye-receiving layer-forming coating solution having the following composition is applied by wire bar coating so that the dry coating amount is 4.0 g / m 2 and dried to form a dye-receiving layer. As a result, a thermal transfer image receiving sheet was obtained.
<Dye-receiving layer forming coating solution>
Vinyl chloride-vinyl acetate copolymer resin (Solvine C, manufactured by Nissin Chemical Industry Co., Ltd.)
(Vinyl chloride / vinyl acetate = 87/13, number average molecular weight 31,000, glass transition temperature 70 ° C.) 20.0 parts Carboxyl-modified silicone (X-22-3701E, manufactured by Shin-Etsu Chemical Co., Ltd.)
1.0 part methyl ethyl ketone / toluene (mass ratio 1: 1) 79.0 parts

(Evaluation of rainbow unevenness and gloss)
The results of evaluating the rainbow unevenness and the glossiness of the protective layer thermal transfer sheets obtained in Examples 1 to 9 and Comparative Examples 1 to 4 were as shown in Table 1 above.

  The evaluation criteria for rainbow unevenness and glossiness are as follows.

Evaluation of rainbow unevenness Rainbow mura was evaluated by printing a solid black image with a sublimation transfer printer manufactured by Citizen Systems Co., Ltd. and visually checking the printed matter, and was ranked as follows.
○: No rainbow unevenness when observed under fluorescent light ×: Rainbow unevenness is observed when observed under fluorescent light

Glossiness Evaluation Glossiness is measured by using a sublimation transfer printer manufactured by Citizen Systems Co., Ltd. to print a black solid image on the right side and a white solid surface on the left side. Nippon Denshoku Co., Ltd.)) and a measurement angle of 20 ° and a measurement direction MD (main scanning direction).

  Note that Comparative Example 1 and Comparative Example 4 were not able to be used as a protective layer thermal transfer sheet because of the drop of the foil and a decrease in scratch resistance.

DESCRIPTION OF SYMBOLS 1 Protective layer thermal transfer sheet 2 Base film 3 Release layer 4 Primer layer 5 Heat seal layer

Claims (6)

A base film;
A protective layer thermal transfer sheet comprising a protective layer formed on at least a part of one surface of the base film so as to be capable of thermal transfer,
The release layer formed at the interface on the base film side of the protective layer is a resin composition comprising an acrylic resin and a styrene acrylic resin in combination, and with respect to the total amount of the resin composition, A protective layer thermal transfer sheet comprising 30 to 60% by weight of the acrylic resin and 40 to 70% by weight of a styrene acrylic resin.   The protective layer thermal transfer sheet according to claim 1, wherein the protective layer is formed in the order of a release layer, a primer layer, and a heat seal layer from the base film side.   The protective layer thermal transfer sheet according to claim 1, wherein the release layer has a thickness of 0.1 μm to 10 μm.   The protective layer thermal transfer sheet according to any one of claims 1 to 3, wherein a dye layer is formed on the same surface as the surface on which the protective layer of the base film is formed.   The protective layer thermal transfer sheet according to any one of claims 1 to 4, wherein a back slip layer is formed on a surface of the base film opposite to the surface on which the protective layer is formed.   A printed matter obtained by transferring the protective layer of the protective layer thermal transfer sheet according to any one of claims 1 to 5.

Images