JP4489679B2 - Protective layer thermal transfer sheet and image-formed product using the same - Google Patents

Description

  The present invention relates to a protective layer thermal transfer sheet, and more specifically, by transferring the thermal transferable protective layer of the protective layer thermal transfer sheet to the thermal transfer image surface of the transfer object even under severe use conditions, The present invention relates to a protective layer thermal transfer sheet for improving various durability such as abrasion resistance and plasticizer resistance of the thermal transfer image and an image formed product using the same.

In the present specification, “ratio”, “part”, “%” and the like indicating the blending are based on mass unless otherwise specified, and the “/” mark indicates that they are integrally laminated.
In the present specification, the ionizing radiation curable resin is a precursor or composition before curing without irradiation with ionizing radiation, and a material cured by irradiation with ionizing radiation is referred to as ionizing radiation curable resin.

  (Main applications) The main applications of the image-formed product using the protective layer thermal transfer sheet of the present invention include, for example, proof printing, image output, CAD / CAM design and design output, CT scan, etc. As an alternative to instant photo analysis, medical analyzers such as medical cameras and endoscope cameras, and output of identification photos, credit cards, ID cards, prepaid cards, and other cards Furthermore, since it cannot be reproduced with color copies, such as composite photos at amusement facilities such as amusement parks, game centers, museums, and aquariums, as commemorative photos, gift certificates, checks, bills, stock certificates, admission tickets, various certificates, etc. Because of their unique design and packaging properties, they are packaging materials, books, pamphlets, POPs, and the like. It is intended to improve the protective properties of these outermost surfaces. However, the application is not particularly limited as long as the application requires durability such as wear resistance and plasticizer resistance.

(Background Art) An image such as a face photograph for personal authentication and confirmation is provided on an image formed product which is the above-mentioned use. Various printing methods for forming the image include thermal sublimation transfer in which the dye in the color material layer sublimates and diffuses by heat and the dye moves to the image receiving sheet, and the color material layer melts and softens by heating, and the color material layer itself receives the image. Thermally sensitive transfer, ink jet, and electrophotography that are transferred to a sheet are widely used. Among them, thermal sublimation transfer can be dyed with a sublimation dye and a thermal transfer sheet in which a dye layer in which a sublimation transfer dye used as a recording material is melted or dispersed in a binder resin is supported on a base material sheet such as a polyester film. There has been proposed a method of superimposing an image receiving sheet on which a receiving layer is formed on a material to be transferred, such as paper or plastic film, and thermally transferring a sublimation transfer dye to form various full strength images.
In this case, a thermal head of the printer is used as the heating means, and the color dots in which a large number of heating amounts of three colors or four colors are adjusted are transferred to the image receiving sheet by heating for a very short time. The color dots reproduce the full color of the document. The image formed in this way is very clear and excellent in transparency because the coloring material used is a dye, so the resulting image is excellent in reproducibility and gradation of intermediate colors, It is possible to form a high-quality image similar to a conventional image by offset printing or gravure printing and comparable to a full-color photographic image. At present, a thermal transfer recording method is widely used as a simple printing method. Since the thermal transfer recording method can easily form various images, the thermal transfer recording method is used in printed matter that requires a relatively small number of printed sheets, such as ID card creation, business photographs, personal computer printers, and video printers.
Thermal transfer images recorded by the thermal sublimation transfer method or thermal fusion transfer method are used, but the thermal transfer image recorded by the thermal sublimation transfer method in particular is the amount of dye transfer in dots by the amount of energy applied to the thermal transfer sheet. However, unlike the ordinary printing ink, the color image is not a pigment but a relatively low molecular weight dye, and the vehicle is excellent in forming a gradation image. Since it does not exist, there is a disadvantage that it is inferior in durability such as light resistance, weather resistance, and abrasion resistance. In addition, there is a drawback that the durability of the solution such as alcohol, which is common in general households, is poor in chemical resistance and solvent resistance. Furthermore, there is a defect that the image is miserable when it comes into contact with a card case, a file sheet, a plastic eraser, or the like containing a plasticizer, and the plasticizer resistance is inferior, such as migration of dyes to these contacts.
As a means for solving the above drawbacks, there is a method of forming a protective layer on the formed image. The method of transferring and forming the protective layer can use the same thermal head as the image formation during image formation, so the device is simpler and less expensive than laminating or pouching a molded film. On the other hand, the plasticizer resistance was insufficient. In particular, when a printed product obtained by thermally transferring a protective layer to an image-receiving sheet on which an image is formed is stored in contact with a card case containing a plasticizer, a file sheet, a plastic eraser, etc., an image of the printed product is formed. The dye moves to the case side, the case is contaminated, the density of the printed matter is reduced, or the printed matter is adhered to the contact surface with a card case containing plasticizer, file sheet, plastic eraser, etc. There is a problem that the image is destroyed when taken out.
In order to solve the above-mentioned problems, the object of the present invention is to superimpose a protective layer thermal transfer sheet having a thermal transfer resin layer on a thermal transfer image recorded by a thermal sublimation transfer method at low cost and easily. A method of forming a protective layer by transferring a thermal transfer resin layer using a thermal head or a heating roll is known. However, the formation of a protective layer imparts durability such as scratch resistance and plasticizer resistance to the transfer target, and the foil breakability during transfer to the transfer target, and the laminateability of the transferred protective layer (delamination does not occur). The transferability such as not occurring) was incompatible.
Therefore, even if the protective layer thermal transfer sheet is subjected to severe use conditions, by transferring the thermal transferable protective layer of the protective layer thermal transfer sheet to the thermal transfer image surface of the transfer target, the wear resistance, When the thermal transfer image is stored in contact with a plastic case containing a plasticizer, a plastic eraser, etc., the case is not contaminated or the density of the printed matter does not decrease, such as plasticizer resistance, light resistance, etc. Thermal transfer images with excellent durability can be obtained, and transfer properties such as foil tearability and lamination of the transferred protective layer (no delamination) occur during transfer, and the image formed is bent after transfer. Therefore, there is a demand for a protective layer thermal transfer sheet that does not easily crack even if it is damaged.

(Prior Art) Conventionally, the present applicant has disclosed a protective layer containing an acrylic resin containing at least one of an alicyclic compound and an aromatic compound and at least one of a hydroxyl group-containing compound as a protective layer for a thermal transfer image. A transfer sheet is disclosed (for example, see Patent Document 1). However, a printed matter having an image having excellent durability such as plasticizer resistance and light resistance can be obtained, but foil breakability at the time of transfer of the protective layer, laminating property of the transferred protective layer (delamination does not occur) Etc.) has a drawback of poor transferability.
Further, the present applicant has disclosed a protective layer transfer sheet mainly composed of an acrylic resin and a protective layer transfer sheet mainly composed of a polyester resin as a protective layer for a thermal transfer image (see, for example, Patent Document 2). However, against the case made of vinyl chloride, the dye is prevented from fading by light of the dye forming the image without transferring or fusing the case to the case, and the obtained printed matter is resistant to water, alcohol, etc. It has a drawback that it has poor transferability such as foil breakage during transfer of the protective layer and lamination of the transferred protective layer (no delamination). .
Accordingly, the present applicant further includes a copolymer of at least two components of methyl methacrylate, methacrylamide and methacrylic acid as a protective layer for a thermal transfer image with improved transferability, and the adhesive layer is made of methacrylic acid. Protective layer containing one of the group consisting of methyl, butyl methacrylate and a copolymer of methyl methacrylate and butyl methacrylate, or a mixture of at least one of this group and a ketone resin A thermal transfer sheet is disclosed (for example, see Patent Document 3). However, there is a problem that when the image formed product is bent after the transfer, it cracks and the appearance is deteriorated.

JP 2001-347759 A JP 2002-240404 A JP 2003-80844 A

  Accordingly, the present invention has been made to solve such problems. The purpose is to transfer a protective layer with good transferability to the transfer target having a thermal transfer image, such as a foil cutting property and a laminate property of the transferred protective layer (no delamination). Gives excellent durability such as abrasion resistance and plasticizer resistance to the thermal transfer image on the transfer body, and it is hard to crack even if the image formation after transfer is bent, and the appearance deteriorates. It is an object of the present invention to provide a difficult protective layer thermal transfer sheet and an image formed product using the same.

In order to solve the above-mentioned problems, the protective layer thermal transfer sheet according to the invention of claim 1 is a protective layer thermal transfer sheet in which a thermal transferable protective layer is provided on a substrate, wherein the thermal transferable protective layer is at least a thermal transfer resin layer, an adhesive The layers are formed in this order, and the thermal transfer resin layer is a mixture of (1) a trimer of isophorone diisocyanate , (2) a urethane (meth) acrylate oligomer which is a reaction product of pentaerythritol triacrylate , and a methacrylic resin. It is made to be a cured product of a certain ionizing radiation curable resin.
The protective layer thermal transfer sheet according to the invention of claim 2 is such that the mass-based ratio of the ionizing radiation curable resin is urethane (meth) acrylate oligomer: methacrylic resin = 1: 2 to 3: 1. It is.
A protective layer thermal transfer sheet according to the invention of claim 3 is such that a layer containing titanium oxide is provided between the thermal transfer resin layer and the adhesive layer .
The image-formed product according to the invention of claim 4 is formed by providing a heat transferable protective layer on the heat transfer image surface of the transfer object using the protective layer thermal transfer sheet according to any one of claims 1 to 3. , That is.

  (Points of the Invention) The present inventors have further conducted earnest research from Japanese Patent Application Laid-Open No. 2002-240404 filed by the applicant of the present application. Focusing on achieving both durability against images and cracking resistance of the image-formed product after transfer, in the present invention, by limiting the thermal transfer resin layer of the thermal transferable protective layer, transferability and durability The present application was able to improve the crack resistance.

According to the present invention of claim 1 or 2, with respect to a transfer body having a thermal transfer image, foil cutting property of the protective layer, transfer property such as a multilayer of the transferred protective layer (that delamination does not occur) It can be transferred well, imparts excellent wear resistance, plasticizer resistance and other durability to the thermal transfer image on the transferred material, and cracks even if the image formed after the transfer is bent. Provided is a protective layer thermal transfer sheet having a protective layer that is difficult to break and whose appearance is difficult to deteriorate.
According to the third aspect of the present invention, there is provided a protective layer thermal transfer sheet which is more excellent in durability against a thermal transfer image and crack resistance of an image-formed product after transfer.
According to the fourth aspect of the present invention, there is provided an image formed article having durability such as wear resistance and plasticizer resistance, and a thermal transfer image which hardly cracks even if the image formed article after transfer is bent. .

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic cross-sectional view of a protective layer thermal transfer sheet showing one embodiment of the present invention.
FIG. 2 is a schematic plan view and sectional view of a protective layer thermal transfer sheet showing one embodiment of the present invention.
FIG. 3 is a schematic cross-sectional view of a protective layer thermal transfer sheet showing one embodiment of the present invention.
FIG. 4 is a schematic cross-sectional view of an image-formed product showing one embodiment of the present invention.

(Configuration of Protective Layer Thermal Transfer Sheet) As shown in FIG. 1, the protective layer thermal transfer sheet 10 of the present invention is provided with at least a thermal transferable protective layer 21 on one surface of a substrate 11, and the thermal transferable protective layer. Reference numeral 21 denotes a layer configuration including the thermal transfer resin layer 15 and the adhesive layer 17.
As shown in FIG. 2, if necessary, a release layer 13 is provided between the base material 11 and the heat transferable resin layer 15 to stabilize the release, or heat resistance during transfer is increased. A back layer 41 is provided on the other surface of the substrate 11, or other layers such as a layer 18 containing titanium oxide are provided between the heat transferable resin layer 15 and the adhesive layer 17 in order to further enhance the durability. May be.
Further, as shown in FIG. 3, the protective layer thermal transfer sheet 10 of the present invention has a heat sublimable color material layer or a heat meltable color material layer in a region other than the region where the thermal transfer resin layer 15 is formed on the substrate. Of these, at least one region may be provided in the surface order.
The thermal transfer resin layer 15 includes (1) an isocyanate having 3 or more isocyanate groups in the molecule, and (2) a polyfunctional (meta) having at least one hydroxyl group and at least two (meth) acryloyloxy groups in the molecule. A cured product of ionizing radiation curable resin containing urethane (meth) acrylate oligomer which is a reaction product of acrylates or (3) polyhydric alcohols having at least two hydroxyl groups in the molecule.

  (Base material of protective layer thermal transfer sheet) As the base material 11, various materials can be used depending on the application as long as it has heat resistance, mechanical strength, mechanical strength, solvent resistance, etc. Is applicable. For example, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene terephthalate-isophthalate copolymer, terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer, polyethylene terephthalate / polyethylene naphthalate coextruded film Polyamide resins such as nylon 6 and nylon 66, polyolefin resins such as polyethylene, polypropylene and polymethylpentene, vinyl resins such as polyvinyl chloride, acrylic resins such as polyacrylate, polymethacrylate and polymethyl methacrylate Imide resins such as polyimide and polyetherimide, polyarylate, polysulfone, polyethersulfone, polyphenylene Engineering resins such as lenether, polyphenylene sulfide (PPS), polyaramid, polyetherketone, polyethernitrile, polyetheretherketone, polyethersulfite, and styrenes such as polycarbonate, polystyrene, high impact polystyrene, AS resin, and ABS resin Examples thereof include resin, cellophane, cellulose acetate, and cellulose-based films such as nitrocellulose.

  The substrate may be a copolymer resin containing these resins as a main component, a mixture (including an alloy), or a laminate composed of a plurality of layers. The 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. The substrate is used as a film, sheet or board formed of at least one layer of these resins. Usually, a polyester film such as polyethylene terephthalate or polyethylene naphthalate is preferably used because of its good heat resistance and mechanical strength, and polyethylene terephthalate is most suitable. The thickness of the base material is usually about 2.5 to 50 μm, and preferably 2.5 to 25 μm. If the thickness is greater than this, the heat transfer of the thermal head is poor, and if it is less than this, the mechanical strength is insufficient. Prior to application, the substrate is subjected to corona discharge treatment, plasma treatment, ozone treatment, flame treatment, primer (also called an anchor coat, adhesion promoter, or easy adhesive) application treatment, pre-heat treatment, dust removal treatment. Alternatively, easy adhesion treatment such as vapor deposition treatment or alkali treatment may be performed. Moreover, you may add additives, such as a filler, a plasticizer, a coloring agent, and an antistatic agent, as needed.

  (Peeling layer) In order to stabilize and improve the transferability at the time of transfer, it is preferable to provide the peeling layer 13 between the substrate 11 and the heat transferable resin layer 15. As the resin for the release layer 13, a release resin, a resin containing a release agent, a curable resin that is cross-linked by ionizing radiation, or the like can be used. The releasable resin is, for example, a fluorine resin, silicone, melamine resin, epoxy resin, polyester resin, acrylic resin, fiber resin, wax, melamine resin, or the like. The resin containing the release agent is, for example, an acrylic resin, vinyl resin, polyester resin, or fiber resin obtained by adding or copolymerizing a release agent such as fluorine resin, silicone, or various waxes. is there. The curable resin that is cross-linked by ionizing radiation is, for example, a resin containing a monomer or oligomer having a functional group that is polymerized (cured) by ionizing radiation such as ultraviolet (UV) or electron beam (EB).

  As a material for the release layer 13, a general thermoplastic resin can be used. Usable resins include cyclic olefin resins, norbornene resins, polycarbonate resins, polyarylate resins, polyamideimide resins, polyetherimide resins, polysulfone resins, and the like. Cyclic olefin resins are preferred, and norbornene resins are more preferred. The material of the release layer may be a copolymer resin containing these resins as a main component, or a mixture (including an alloy). The thermoplastic resin preferably has a glass transition temperature (Tg) of 120 to 200 ° C.

  Examples of the cyclic olefin-based resin containing a cyclic structure include (a) a norbornene polymer, (b) a monocyclic olefin polymer, (c) a cyclic conjugated diene polymer, and (d) a vinyl alicyclic ring. And a hydride of (a) to (d). Among these, from the viewpoint of excellent heat resistance and mechanical strength, a norbornene polymer hydride, a vinyl alicyclic hydrocarbon polymer and a hydride thereof are preferable, and a hydride of a norbornene polymer is more preferable.

(Formation of Release Layer) The release layer 13 is provided on one surface of the substrate 11 as necessary. The release layer 13 is formed by dispersing or dissolving the resin in a solvent and using a known printing or coating method such as roll coating, reverse roll coating, gravure coating, reverse gravure coating, bar coating, or rod coating, at least 1 It may be applied to the part and dried to form a coating film, or a film may be formed by extrusion coating. Further, if necessary, it may be crosslinked by heat drying at a temperature of 30 ° C. to 120 ° C., aging, or irradiation with ionizing radiation.
The thickness of the release layer 13 is usually about 0.01 μm to 5.0 μm, preferably about 0.5 μm to 3.0 μm. The thinner the thickness is, the better. However, when the thickness is 0.1 μm or more, better film formation is obtained and the peeling force is stabilized.

  (Thermal transfer resin layer) The material of the thermal transfer resin layer 15 includes (1) isocyanates having 3 or more isocyanate groups in the molecule, (2) at least one hydroxyl group in the molecule and a (meth) acryloyloxy group. An ionizing radiation curable resin containing a urethane (meth) acrylate oligomer which is a reaction product of a polyfunctional (meth) acrylate having at least two or (3) a polyhydric alcohol having at least two hydroxyl groups in the molecule It is a cured product. Further, the isocyanate having three or more isocyanate groups in the molecule is preferably at least one selected from a trimer of isophorone diisocyanate and a reaction product of isophorone diisocyanate and an active hydrogen-containing compound.

  Regarding the reaction of isocyanates, polyfunctional (meth) acrylates, and polyhydric alcohols, (1) first reacting isocyanates with polyhydric alcohols, ) Reacting acrylates, (2) reacting isocyanates with hydroxyl-containing polyfunctional (meth) acrylates first, and then reacting with polyhydric alcohols, (3) polyhydric alcohols and hydroxyl-containing polyfunctional ( Any method of reacting a mixture with (meth) acrylates with isocyanates can be used. When reaction is performed using at least one of at least one of isocyanates, hydroxyl group-containing polyfunctional (meth) acrylates, and polyhydric alcohols, two or more urethanes are used as reaction products. A mixture of (meth) acrylate oligomers is obtained.

  The total hydroxyl group equivalent of polyhydric alcohols and hydroxyl group-containing polyfunctional (meth) acrylates with respect to 1 equivalent of isocyanate groups in the isocyanate is preferably 0.9 to 1.8 equivalents. When the total hydroxyl group equivalent is less than 0.9 equivalent, the stability of the resin composition after the reaction is lowered, and when it exceeds 1.8 equivalent, sufficient cured properties cannot be obtained.

  The molar ratio of the polyfunctional (meth) acrylates used is preferably 5 to 15 moles per mole of polyhydric alcohols. When there are few polyfunctional (meth) acrylates outside this range, sufficient curability is not obtained by gelation. Moreover, when it exceeds this range and sufficient hardened | cured material property is not obtained.

  Moreover, the mixture of the said urethane (meth) acrylate oligomer and other resin can be used as an ionizing radiation curable resin, and a mixture with a methacryl resin is optimal. As a mixture of a urethane (meth) acrylate oligomer and a methacrylic resin, it is preferable that a mass-based ratio is urethane (meth) acrylate oligomer: methacrylic resin = 1: 2 to 3: 1. When there are many urethane (meth) acrylate oligomers exceeding this range, there is a disadvantage that sufficient formability cannot be obtained, and when there are few urethane (meth) acrylate oligomers exceeding this range, sufficient There is a drawback that heat resistance cannot be obtained.

  In addition, those which can be cured with ionizing radiation without being sticky in a coating state before being cured with ionizing radiation are preferable, and have an isocyanate compound having a melting point of 40 ° C. or more, a (meth) acryloyl group and react with the isocyanate group. It is preferable to use an ionizing radiation curable resin containing a reaction product with the obtained (meth) acrylic compound and having a softening point of 40 ° C. or higher.

  (Ionizing radiation curable resin) The ionizing radiation curable resin becomes an ionizing radiation curable resin (thermal transferable resin layer 15) when it is cured (reacted) by irradiation with ionizing radiation. In the case of ultraviolet curing, ionizing radiation curable resins that cure with ionizing radiation are known light such as acetophenones, benzophenones, Michler benzoyl benzoate, α-amyloxime ester, tetramethylmeurum monosulfide, or thioxanthones. Polymerization initiators and / or known photopolymerization accelerators such as benzoin compounds, anthraquinone compounds, phenyl ketone compounds, sulfide compounds, halogenated hydrocarbons, n-butylamine, tri-n-butylphosphine are added, In the case of electron beam curing with high energy, it may not be added, and if an appropriate catalyst exists, it can be cured even with thermal energy. In addition to the above components, the ionizing radiation curable resin composition may contain various auxiliary agents such as storage stabilizers, accelerators, viscosity modifiers, surfactants, and antifoaming agents as necessary. Also good. Moreover, you may mix | blend polymer bodies, such as a silicone and a styrene-butadiene rubber. When using the above photopolymerization accelerator (photopolymerization initiator, photosensitizer), the content thereof should be used in the range of about 0.5 to 10 parts by mass per 100 parts by mass of the urethane-modified acrylic resin. Is preferred.

  The thermal transfer resin layer 15 is formed by dispersing or dissolving the above composition in a solvent, and using a known printing or coating method such as roll coating, reverse roll coating, gravure coating, reverse gravure coating, bar coating, or rod coating. After applying to at least one part and drying, it may be cured (crosslinked) by irradiation with ionizing radiation. As ionizing radiation, ultraviolet rays (UV), visible rays, gamma rays, X-rays, or electron beams (EB) can be applied. However, ultraviolet rays (UV) are preferred from the standpoint of stable technology because existing equipment can be used. is there. The thermal transfer resin layer 15 is an ionizing radiation cured product obtained by curing an ionizing radiation curable resin with ionizing radiation. The thickness of the thermal transfer resin layer 15 is usually about 0.2 to 10.0 μm, preferably 0. .3 to 5.0 μm.

(Layer containing titanium oxide) In order to further enhance the durability, SiO, SiO ₂ , TiO ₂ , TiO, Al ₂ O ₃ , Sb ₂ O ₃ , ITO are provided between the thermal transfer resin layer 15 and the adhesive layer 17. A transparent thin film layer mainly composed of, for example, may be provided, and a titanium oxide (TiO ₂ ) layer 18 is preferable in terms of transparency and durability. The titanium oxide layer 18 can be obtained by a vacuum thin film method such as a known vacuum deposition method, sputtering method, or ion plating method so as to have a thickness of about 10 to 2000 nm, preferably 20 to 500 nm. If this thickness is above this range, cracks are likely to occur during transfer, and if it is less than this range, durability is low. In addition, this transparent should just permeate | transmit visible light enough, and a colorless or colored and transparent thing is also contained.

  (Adhesive layer) The adhesive layer 17 can be applied with a heat-adhesive adhesive that is melted or softened by heat to adhere, for example, ionomer resin, acid-modified polyolefin resin, ethylene- (meth) acrylic acid copolymer, ethylene- (Meth) acrylic acid ester copolymers, polyester resins, polyamide resins, vinyl resins, acrylic / methacrylic (meth) acrylic resins, acrylic ester resins, maleic resins, butyral resins, Alkyd resin, polyethylene oxide resin, phenolic resin, urea resin, melamine resin, melamine-alkyd resin, cellulose resin, polyurethane resin, polyvinyl ether resin, silicone resin, rubber resin, etc. can be applied. Use alone or in combination. The resin of the adhesive layer 17 is preferably a vinyl resin, an acrylic resin, a butyral resin, or a polyester resin in terms of adhesive strength. More preferable is a maleic acid-vinyl chloride-vinyl acetate copolymer in terms of adhesiveness.

  The thickness of the adhesive layer 17 is usually about 0.05 to 10 μm, preferably 0.1 to 5 μm. If the thickness of the adhesive layer 17 is less than this range, the adhesive force with the transferred material is insufficient and drops off, and if the thickness is higher than that, the adhesive effect is sufficient and the effect remains unchanged, which is wasteful in cost. Furthermore, 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 17 as necessary.

  (Back layer) Further, the back layer 41 may be provided on the other surface of the substrate 11. The back layer 41 includes a heat-resistant thermoplastic resin binder and a substance that functions as a heat release agent or a lubricant as basic constituent components. The thermoplastic resin binder having heat resistance can be selected from a wide range, but preferable examples include acrylic resin, polyester resin, styrene-maleic acid copolymer, polyimide resin, polyamide resin, and polyamideimide resin. , Cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate, vinylidene fluoride resin, nylon, polyvinyl carbazole, chlorinated rubber, cyclized rubber and polyvinyl alcohol. Thermal release agents or lubricants to be blended with the above thermoplastic resins include waxes such as polyethylene wax and paraffin wax, higher fatty acid amides, esters or salts, higher alcohols and phosphate esters such as lecithin. There are those that melt by heating and act on them, and those that are useful as solids, such as fluororesin and inorganic powder.

  The back layer 41 may be formed by a known coating method such as roll coating, reverse roll coating, gravure coating, reverse gravure coating, screen coating, fountain coating, and drying. The back layer 41 has a thickness of about 0.01 to 1.0 μm, preferably 0.1 to 0.2 μm. In this way, by using the protective layer thermal transfer sheet 10 having the back layer 41, the target of the transfer target is enlarged or the transfer (printing, printing) speed is increased, so that the thermal head starts from the back layer 41 surface. Even when high-energy heat printing is performed, since the heat resistance is high, so-called sticking in which the substrate and the thermal head are thermally fused does not occur.

(Sequential Sequential Type) As shown in FIG. 3, at least one region of a heat sublimable color material layer or a heat meltable color material layer is formed in a region other than the region where the thermal transfer resin layer 15 is formed on the substrate. May be used as a protective layer thermal transfer sheet 10 (plane sequential type), and a single ribbon formed of the protective layer thermal transfer sheet 10 (plane sequential type) may form a thermal transfer image and the thermal transfer image surface. A protective layer can be formed. The surface sequential type protective layer thermal transfer sheet 10 may be composed of at least one color material layer region 31 and a thermal transferable protective layer region 33. In the example of FIG. 3, four color material layer regions 31, that is, a Y color material layer region 31 Y, an M color material layer region 31 M, a C color material layer region 31 C, a K color material layer region 31 K, and a thermal transferable protective layer region 33. It has become.
FIG. 3A is an AA cross-sectional view of the Y color material layer region 31Y, and includes a common base material 11, a primer layer 12, and a Y color material layer 31YY as required. The color material layer in the layer region 31 may be a known heat sublimable color material layer or heat meltable color material layer. FIG. 3B is a BB cross-sectional view of the thermal transferable protective layer region 33, which is composed of the base material 11 and the thermal transferable protective layer region 33. The thermal transferable protective layer region 33 is as described above.

  (Image Formed Product) The present invention as shown in FIG. 4 is obtained by transferring and transferring the thermal transferable protective layer 21 to the thermal transfer image surface of the transfer object using the protective layer thermal transfer sheet 10 described above. The image forming product 100 of FIG. The heat transferable protective layer 21 can be transferred to a transfer target having a heat transfer image with good transferability such as foil breakage and laminateability of the transferred protective layer (no delamination occurs). Since the surface of the thermal transfer image on the transfer material is protected by the thermal transferable protective layer 21, it provides excellent durability such as abrasion resistance and plasticizer resistance, and the image formed product after the transfer is bent. Even if it is done, it is hard to crack and the appearance is hard to deteriorate.

  (Transfer to be Transferred) The transfer target 100 is not particularly limited as long as it requires durability such as abrasion resistance and plasticizer resistance. For example, natural fiber paper, coated paper, and tracing paper. Any of plastic film, glass, metal, ceramics, wood, cloth, dye-receptive medium, etc. that does not deform with heat during transfer may be used. The use of the transfer object is as described above, and preferably, further design and security are required. At least a part of the medium of the transfer object 100 is colored, printed, etc. The decoration may be given.

  (Transfer of Thermally Transferable Protective Layer) First, as a method for transferring the thermally transferable protective layer 21 to the transfer object, a known transfer method may be used. For example, hot stamping by hot stamping (foil stamping), entire surface by a hot roll or A known method such as stripe transfer or a thermal printer (also referred to as a thermal transfer printer) using a thermal head (thermal printing head) can be applied. A thermal printer is preferable, and in particular, when the protective layer thermal transfer sheet 10 (surface sequential type) shown in FIG. 3 is used, the thermal transfer image is formed on the transfer target and the thermal transferable protective layer 21 is formed (transferred). Can be performed simultaneously.

  4A shows the case where the thermal transferable protective layer 21 is formed (transferred) on the thermal transfer image surface already provided on the transfer target, and FIG. 4B shows the transfer target using a known intermediate transfer recording medium. This is a case where the thermal transferable protective layer 21 is formed (transferred) on the thermal transfer image surface provided on the body. In short, the thermal transferable protective layer 21 may be formed (transferred) on the thermal transfer image surface. It is not limited.

  EXAMPLES Hereinafter, although an Example and a reference example demonstrate this invention further in detail, it is not limited to this.

<Creation of urethane (meth) acrylate oligomer>
The urethane (meth) acrylate oligomer used in the thermal transfer resin layer coating solution of the following examples was prepared under the following conditions.
A reactor equipped with a stirrer, a reflux condenser, a dropping funnel and a thermometer was charged with 206.0 g of ethyl acetate and 133.0 g of a trimer of isophorone diisocyanate (HULS product, VESTANAT T1890, melting point 110 ° C.), 80 The temperature was raised to 0 ° C. to prepare a solution in which the chemical was dissolved. After blowing air into the solution, 0.38 g of hydroquinone monomethyl ether, 249.0 g of pentaerythritol triacrylate (product of Osaka Organic Chemical Industry Co., Ltd., Viscoat 300) and 0.38 g of dibutyltin dilaurate were charged and reacted at 80 ° C. for 5 hours. Then, 688.9 g of ethyl acetate was added and cooled. It was confirmed by infrared absorption spectrum analysis that the absorption of isocyanate groups in the obtained reaction product solution was extinguished. The softening temperature of the solvent distilled from the reaction product solution was 43 ° C.

(Example 1) A 25 μm thick polyethylene terephthalate (PET) film (manufactured by Toray Industries, Inc., Lumirror) is used as a base material, and on one surface, a back layer coating liquid having the following composition is dried. It was applied and dried by a gravure coating method so as to be 0.15 μm, and a substrate with a back layer was prepared.
・ <Back layer coating liquid>
Silicone-modified acrylic resin (solid content 26%) 10.0 parts (trade name: Polyalloy NSA-X55, manufactured by NATCO)
Toluene / methyl ethyl ketone (mass ratio 1/1) 40.0 parts The release layer, the thermal transfer resin layer, and the adhesive layer were sequentially laminated on the surface opposite to the back layer of the base material with the back layer. A protective layer thermal transfer sheet 10 was produced.
A release layer coating solution having the following composition was applied to the surface opposite to the back layer of the substrate with the back layer so that the thickness after drying by gravure coating was 1.5 μm and dried to form a release layer. . Further, a thermal transfer resin layer coating liquid having the following composition was applied onto the release layer by gravure coating so that the thickness after drying was 2.0 μm, and dried to form a thermal transfer resin layer. Further, an adhesive layer coating solution having the following composition was applied onto the thermal transfer resin layer by gravure coating so that the thickness after drying was 1.0 μm and dried to form an adhesive layer.
・ <Peeling layer coating solution>
Norbornene resin (Nippon Synthetic Rubber Co., Ltd., Arton G) 40 parts Acrylic polyol resin 10 parts (trade name Thermolac SU-100A, manufactured by Soken Chemical Co., Ltd.)
Solvent (methyl ethyl ketone: toluene = 2: 8) 50 parts / <thermal transfer resin layer coating solution>
Urethane (meth) acrylate oligomer 75 parts (This is a urethane (meth) acrylate oligomer prepared under the conditions described above.)
100 parts of methacrylic resin (trade name Parapet GF, manufactured by Kuraray Co., Ltd.)
5 parts of photopolymerization initiator (trade name Irgacure 907, manufactured by Ciba Specialty Chemicals)
Methyl ethyl ketone 100 parts ・ <Adhesive layer coating solution>
Vinyl chloride-vinyl acetate copolymer 20 parts Acrylic resin 10 parts Solvent (ethyl acetate: toluene = 2: 5) 70 parts

Example 2 A protective layer thermal transfer sheet 10 was obtained in the same manner as in Example 1 except that the composition of the thermal transfer resin layer coating solution was as follows.
・ <Heat transfer resin layer coating solution>
60 parts of urethane (meth) acrylate oligomer (a urethane (meth) acrylate oligomer prepared under the conditions described above.)
120 parts of methacrylic resin (trade name Parapet GF, manufactured by Kuraray Co., Ltd.)
5 parts of photopolymerization initiator (trade name Irgacure 907, manufactured by Ciba Specialty Chemicals)
100 parts of methyl ethyl ketone

Example 3 A protective layer thermal transfer sheet 10 was obtained in the same manner as in Example 1 except that the composition of the thermal transfer resin layer coating solution was as follows.
・ <Heat transfer resin layer coating solution>
120 parts of urethane (meth) acrylate oligomer (a urethane (meth) acrylate oligomer created under the conditions described above)
40 parts of methacrylic resin (trade name Parapet GF, manufactured by Kuraray Co., Ltd.)
5 parts of photopolymerization initiator (trade name Irgacure 907, manufactured by Ciba Specialty Chemicals)
100 parts of methyl ethyl ketone

  (Example 4) In the protective layer thermal transfer sheet in Example 1 above, except that a layer formed of titanium oxide with a thickness of 500 mm was formed by vacuum deposition between the thermal transfer resin layer and the adhesive layer, A protective layer thermal transfer sheet 10 was prepared in the same manner as in Example 1.

Example 5 A protective layer thermal transfer sheet 10 was obtained in the same manner as in Example 1 except that the composition of the thermal transfer resin layer coating solution was as follows.
・ <Heat transfer resin layer coating solution>
40 parts of urethane (meth) acrylate oligomer (a urethane (meth) acrylate oligomer prepared under the conditions described above)
120 parts of methacrylic resin (trade name Parapet GF, manufactured by Kuraray Co., Ltd.)
5 parts of photopolymerization initiator (trade name Irgacure 907, manufactured by Ciba Specialty Chemicals)
100 parts of methyl ethyl ketone

Example 6 A protective layer thermal transfer sheet 10 was obtained in the same manner as in Example 1 except that the composition of the thermal transfer resin layer coating solution was as follows.
・ <Heat transfer resin layer coating solution>
120 parts of urethane (meth) acrylate oligomer (a urethane (meth) acrylate oligomer created under the conditions described above)
30 parts of methacrylic resin (trade name Parapet GF, manufactured by Kuraray Co., Ltd.)
5 parts of photopolymerization initiator (trade name Irgacure 907, manufactured by Ciba Specialty Chemicals)
100 parts of methyl ethyl ketone

Comparative Example 1 A protective layer thermal transfer sheet of Comparative Example 1 was obtained in the same manner as in Example 1 except that the composition of the thermal transfer resin layer coating solution was as follows.
・ <Heat transfer resin layer coating solution>
100 parts of methacrylic resin (trade name Parapet GF, manufactured by Kuraray Co., Ltd.)
100 parts of methyl ethyl ketone

First, a thermal transfer sheet provided with a standard dye layer for a card printer CP510 made by VDS is used as a thermal transfer sheet, and a card base under the following conditions is used as a transfer target, with the dye layer and the image receiving surface facing each other. Thermal transfer recording was performed using the thermal head from the back side of the thermal transfer sheet in the order of superposition, Y, M, and C under the following conditions to form a gray gradation image.
<Material composition of card base>
Polyvinyl chloride compound (degree of polymerization 800) 100 parts (contains about 10% of additives such as stabilizers)
White pigment (titanium oxide) 10 parts Plasticizer (DOP) 0.5 parts

(Printing conditions)
Thermal head: KGT-217-12MPL20 (manufactured by Kyocera Corporation)
-Heating element average resistance: 3195 (Ω)
・ Print density in the main scanning direction: 300 dpi
-Sub-scanning direction printing density: 300 dpi
Applied power: 0.12 (w / dot)
1 line cycle: 5 (msec.)
-Printing start temperature: 40 (° C)
Gradation control method: Using a multi-pulse test printer that can vary the number of divided pulses from 0 to 255 in one line period and having a pulse length obtained by equally dividing one line period into 256. The duty ratio is fixed at 60%, and the number of pulses per line period is increased by 0 in the 0 step, 17 in the 1 step, 34 in the 2 step, and from 0 to 255 in increments of 17 depending on the gradation. Thus, 16 gradations from 0 step to 15 steps were controlled.

(Protective layer transfer)
Next, a protective layer was transferred and formed on the gradation image formed as described above. For the printed matter subjected to the above thermal transfer recording, the protective layer thermal transfer sheets of Examples and Comparative Examples were overlapped with the protective layer surface and the image receiving surface facing each other, and a protective layer was formed on the entire print screen by a thermal head under the following printing conditions. Transcribed.

(Printing conditions)
Thermal head: KGT-217-12MPL20 (manufactured by Kyocera Corporation)
-Heating element average resistance: 3195 (Ω)
・ Print density in the main scanning direction: 300 dpi
-Sub-scanning direction printing density: 300 dpi
Applied power: 0.12 (w / dot)
1 line cycle: 5 (msec.)
-Printing start temperature: 40 (° C)
・ Applied pulse: Duty ratio of each divided pulse using a multi-pulse test printer that can vary the number of divided pulses with a pulse length that is equally divided into 256 in one line period from 0 to 255 Was fixed to 60%, the number of pulses per line period was fixed to 210, solid printing was performed, and the protective layer was transferred to the entire printing screen.

(Evaluation and evaluation method) Abrasion resistance test, flex resistance test, plasticizer resistance test, and light resistance test were carried out using the prints obtained by transferring the protective layer obtained in the above examples and comparative examples. And evaluated.
The abrasion resistance test (Taber test) is based on ANSI-INCITS 322-2002, 5.9 Surface Ablation, and the degree of wear is visually observed every predetermined number of cycles, and the image that can be visually recognized is good. An image whose surface was worn and the visibility of the image was deteriorated or defective was regarded as defective. Good ones even at 1500 cycles were accepted as “◎”, good ones were accepted at 1000 cycles, “◯”, and bad ones were rejected at 1000 cycles, and indicated by “x”.
The bending resistance test is based on ANSI-INCITS 322-2002, 5.4 Card Flexure, and the surface of the image formed product after the test is visually observed, and passes the one where the difference between the bent part and the non-bent part is not seen. “○”, and those with obvious deterioration at the bent portion were rejected and indicated by “×”.
In the plasticizer resistance test, Altron (vinyl chloride sheet) manufactured by Mitsubishi Chemical Corporation was used, and the sheet and the image surface of the printed material obtained after the transfer of the protective layer were overlapped. The condition after standing for 100 hours at / cm ² , storage environment at 50 ° C. and dry was observed with the naked eye. Evaluation was performed according to the following criteria. If no image omission is seen at all, it is accepted as “◎”, and image omission is slightly seen, but if there is no problem in actual use, it is accepted as “O”, and clear omission in the image is seen. The result was indicated as “x”.
In the light resistance test, the light resistance test was performed on the printed matter obtained above after transfer of the protective layer using a super xenon weather meter under the following conditions.
・ <Conditions>
Irradiation tester: SX75, manufactured by Suga Test Instruments
Light source: Xenon lamp Outer filter: # 275
Inner filter: quartz Plaque panel temperature: 50 ° C
Irradiance: 48 W / m ² (measured value at 300 to 400 nm)
Integrated irradiance: 16.0 mJ / m ² (96 hours)
Next, using a color difference meter (CR-221 manufactured by Minolta Co., Ltd.), the color difference (ΔEab) before and after irradiation of a gray pattern (optical reflection density of about 1.0) created with three colors of Ye, Mg, and Cy is obtained. It was measured. A sample having a color difference ΔEab <20 was accepted as “「 ”, a sample having ΔEab <30 was accepted as“ ◯ ”, and a sample having ΔEab> 30 was rejected.

(Evaluation results) Table 1 shows the evaluation results.
In Examples 1 to 6, all evaluations were “pass = ◎” or “pass = ◯”. However, in Example 4, all the test items were “pass = ◎”. Further, in the thermal transfer resin layer constituting the thermal transferable protective layer of the protective layer thermal transfer sheet, the mass-based ratio of the ionizing radiation curable resin is a range of urethane (meth) acrylate oligomer: methacrylic resin = 1: 2 to 3: 1. In Examples 5 and 6, which are out of the range, “pass = ◯” in all test items, the evaluation results are slightly inferior to those of the other examples. In all of Examples 1 to 4, in the thermal transfer resin layer, the mass-based ratio of the ionizing radiation curable resin is within the range of urethane (meth) acrylate oligomer: methacrylic resin = 1: 2 to 3: 1.
In Comparative Example 1, all of the evaluation items were “failed = ×”.

It is typical sectional drawing of the protective layer thermal transfer sheet which shows one Example of this invention. It is the typical top view and sectional drawing of a protective layer thermal transfer sheet which show one Example of this invention. It is typical sectional drawing of the protective layer thermal transfer sheet which shows one Example of this invention. 1 is a schematic cross-sectional view of an image-formed product showing one embodiment of the present invention.

Explanation of symbols

10: Protective layer thermal transfer sheet 11: Base material 12: Primer layer 13: Release layer 15: Thermal transferable resin layer 17: Adhesive layer 19: Layer containing titanium oxide 21: Thermal transferable protective layer 31: Color material layer region 33: Thermal transferable protective layer region 41: Back layer 100: Image formed product 101: Transfer object

Claims (4)

In a protective layer thermal transfer sheet provided with a thermal transferable protective layer on a substrate, the thermal transferable protective layer is formed with at least a thermal transfer resin layer and an adhesive layer in this order, and the thermal transfer resin layer is composed of (1) a trimer of isophorone diisocyanate. And (2) a protective layer thermal transfer sheet which is a cured product of an ionizing radiation curable resin which is a mixture of a urethane (meth) acrylate oligomer which is a reaction product of pentaerythritol triacrylate and a methacrylic resin . The protective layer thermal transfer sheet according to claim 1 , wherein the mass-based ratio of the ionizing radiation curable resin is urethane (meth) acrylate oligomer: methacrylic resin = 1: 2 to 3: 1 . The protective layer thermal transfer sheet according to claim 1 , wherein a layer containing titanium oxide is provided between the thermal transfer resin layer and the adhesive layer . Using protective layer thermal transfer sheet according to any one of claims 1 to 3, the thermal transfer image surface of the transfer receiving material, image formation characterized by comprising providing a thermally transferable protective layer.

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