JP6019620B2 - Protective layer transfer sheet - Google Patents

Description

  The present invention relates to a protective layer transfer sheet.

  As a method of forming an image using thermal transfer, a sublimation type thermal transfer sheet in which a sublimable dye is supported on a substrate such as a plastic film, and a thermal transfer image receiving image in which a dye receiving layer is provided on a substrate such as paper or plastic film. A sublimation thermal transfer method is known in which a sheet is superposed on each other to form a full color image. Since this method uses sublimation dyes as color materials, it has excellent reproducibility and gradation of intermediate colors, and can express full-color images exactly as they are on a thermal transfer image-receiving sheet. It is applied to color image formation for computers. The image is of a high quality comparable to a silver salt photograph.

  By the way, the sublimation type thermal transfer method can control the transfer amount of the dye in dot units according to the amount of energy applied, so it is excellent in forming a gradation image, but the formed image is based on ordinary printing ink. In contrast, the coloring material is not a pigment but a dye having a relatively low molecular weight, and there is a disadvantage that physical durability is inferior because there is no vehicle.

  Therefore, a protective layer transfer sheet having a transferable protective layer is superimposed on an image obtained by the sublimation type thermal transfer method, and the transferable protective layer is transferred using a thermal head, a heating roll, etc. Attempts have been made to form a transferable protective layer. For example, Patent Document 1 includes a transferable protective layer on a substrate, and the transferable protective layer includes a layer mainly composed of an acrylic resin and a layer mainly composed of a polyester resin in this order from the substrate side. A laminated protective layer transfer sheet having a laminated structure is disclosed. Patent Document 2 discloses a protective layer transfer sheet including a transferable protective layer containing at least an alicyclic polyester resin in which a diol component and an acid component have one or more alicyclic compounds. According to the protective layer transfer sheet disclosed in these patent documents, various durability can be imparted to the printed matter on which the image is formed.

JP 2002-240404 A Japanese Patent No. 377052

  However, the protective layer transfer sheet that has been variously studied so far has various durability and plasticizers for the layer located on the outermost surface after the transferable protective layer is transferred onto the printed matter on which the image is formed. However, no attention has been paid to the plasticizer resistance of the layer in direct contact with the image. For example, the layer mainly composed of a polyester resin in the protective layer transfer sheet disclosed in Patent Document 1 is in direct contact with the image when the transferable protective layer is transferred onto the image due to its configuration. However, when the layer mainly composed of polyester is in direct contact with the image, the dye of the image moves to the layer mainly composed of polyester, and the image is blurred. Furthermore, when the dye of the image migrates, the layer mainly composed of polyester becomes soft and the plasticizer resistance further decreases.

  In addition, the transferable protective layer containing at least an alicyclic polyester resin in which the diol component and the acid component disclosed in Patent Document 2 have one or more alicyclic compounds is considered with respect to plasticizer resistance. In the same manner as described above, bleeding occurs in the image, and the transferable protective layer has low plasticizer resistance on the surface of the printed material after transfer.

  In the case where the transferable protective layer is used as a single layer, in order to improve the plasticizer resistance, it is important to use a material excellent in plasticizer resistance, but when focusing on the plasticizer resistance, The problem is that transferability onto an image is deteriorated and tailing occurs during transfer. On the other hand, when attention is paid to improvement of transferability and prevention of tailing, plasticizer resistance and scratch resistance are reduced. In addition to this, since the transferable protective layer is easily colored by the dye, when the roll-back storage was performed so that the back layer and the transferable protective layer where the dye was kicked face each other, the back layer was kicked. The dye backs to the transferable protective layer. In other words, whether the transferable protective layer is a single layer or a laminated structure, at present, it has excellent plasticizer resistance, scratch resistance, and transferability, and there is no occurrence of tailing or back. It is difficult to form a transferable protective layer.

  The present invention has been made in view of such a situation, and can impart plasticizer resistance and scratch resistance to an image so that the back layer and the transferable protective layer kicked by the dye face each other. Even when winding and storing, it is possible to prevent the dye kicked to the back layer from backing to the transferable protective layer and to prevent tailing during transfer of the transferable protective layer, and to transfer onto the image. The main object is to provide a protective layer transfer sheet having excellent properties.

This invention for solving the said subject is a protective layer transfer sheet which has a base material and the transferable protective layer provided on the base material so that peeling was possible, Comprising: The said transferable protective layer is (A) glass. A first polyester resin having a transition temperature (Tg) of 50 ° C. or higher and a number average molecular weight (Mn) of less than 6000; and (B) a glass transition temperature (Tg) of 50 ° C. or higher, and a number average molecular weight (Mn) ) Is 23000 or more and 25000 or less of the second polyester resin, and the (A) first is based on the total mass of the (A) first polyester resin and the (B) second polyester resin. The content of the polyester resin is in the range of 10% by mass to 35% by mass.
Moreover, the protective layer transfer sheet of one embodiment is a protective layer transfer sheet having a substrate and a transferable protective layer provided on the substrate in a peelable manner, wherein the transferable protective layer is (A) A first polyester resin having a glass transition temperature (Tg) of 50 ° C. or higher and a number average molecular weight (Mn) of less than 6000; and (B) a glass transition temperature (Tg) of 50 ° C. or higher and a number average molecular weight ( And a second polyester resin having a Mn) of 10,000 to 25,000.

  Further, the content of the first polyester resin (A) is 10% by mass to 35% by mass with respect to the total mass of the (A) first polyester resin and the (B) second polyester resin. It may be within the range. Further, the transferable protective layer has a structure in which a peeling layer and an adhesive layer are laminated in this order from the substrate side, and the adhesive layer includes the (A) first polyester resin and the (B). A second polyester resin may be included.

  Moreover, a release layer may be provided between the base material and the transferable protective layer.

  According to the thermal transfer sheet of the present invention, it is possible to impart plasticizer resistance and scratch resistance to an image, and when winding and storage is performed so that the back layer on which the dye is kicked faces the transferable protective layer Even so, it is possible to prevent the dye kicked to the back layer from backing to the transferable protective layer and to cause tailing during transfer of the transferable protective layer, and to be excellent in transferability onto an image.

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

  Embodiments of the present invention will be specifically described with reference to the accompanying drawings.

  As shown in FIGS. 1 and 2, the protective layer transfer sheet 10 of the present invention includes a base material 1 and a transferable protective layer 20 provided on the base material 1 so as to be peelable. In the protective layer transfer sheet 10 of the present invention, the transferable protective layer 20 is a first polyester resin in which (A) the glass transition temperature (Tg) is 50 ° C. or higher and the number average molecular weight (Mn) is less than 6000. And (B) a second polyester resin having a glass transition temperature (Tg) of 50 ° C. or higher and a number average molecular weight (Mn) of 10,000 to 25,000.

  In the specification of the present application, the glass transition temperature (Tg) is a temperature obtained based on measurement of a change in calorie (DSC method) by DSC (differential scanning calorimetry). The number average molecular weight (Mn) is a value measured by gel permeation chromatography (GPC) using polystyrene as a standard substance.

(Base material)
The substrate 1 used in the protective layer transfer sheet 10 of the present invention is not particularly limited as long as it has a certain degree of heat resistance and strength, and a conventionally known material can be appropriately selected and used. . As such a substrate 1, for example, a polyethylene terephthalate film, a 1,4-polycyclohexylenedimethylene terephthalate film, a polyethylene naphthalate film, a polyphenylene sulfide having a thickness of about 0.5 μm to 50 μm, preferably about 1 μm to 10 μm. Film, polystyrene film, polypropylene film, polysulfone film, aramid film, polycarbonate film, polyvinyl alcohol film, cellophane, cellulose derivatives such as cellulose acetate, polyethylene film, polyvinyl chloride film, nylon film, polyimide film, ionomer film, etc. .

(Transferable protective layer)
As shown in FIGS. 1 and 2, a transferable protective layer 20 is provided on the substrate 1. FIG. 1 is a schematic cross-sectional view showing an example of a protective layer transfer sheet when the transferable protective layer 20 has a single-layer structure, and FIG. 2 shows that two or more layers of the transferable protective layer 20 are laminated. FIG. 3 is a schematic cross-sectional view showing an example of a protective layer transfer sheet having a laminated structure (in the case shown in FIG. 2, a transferable protective layer having a two-layer structure).

  The transferable protective layer 20 is provided so as to be peelable from the base material 1, and the protective layer transfer sheet 10 of the present invention and the printed material on which the image is formed are overlapped to provide the transferable protective layer 20 of the base material 1. This is a layer which is peeled off from the substrate 1 by being heated by a conventionally known heating means such as a thermal head and transferred onto the printed material. In the present invention, the transferable protective layer 20 comprises (A) a first polyester resin having a glass transition temperature (Tg) of 50 ° C. or higher and a number average molecular weight (Mn) of less than 6000, and (B) The glass transition temperature (Tg) is 50 ° C. or higher, and the number average molecular weight (Mn) is 10,000 to 25000 or less. Hereinafter, (A) the first polyester resin having a glass transition temperature (Tg) of 50 ° C. or higher and a number average molecular weight (Mn) of less than 6000 is simply referred to as “first polyester resin”, and (B) the glass transition. The second polyester resin having a temperature (Tg) of 50 ° C. or higher and a number average molecular weight (Mn) of 10,000 or more and 25,000 or less may be simply referred to as “second polyester resin”.

  In the present invention, since the transferable protective layer 20 includes both the first polyester resin and the second polyester resin, the printed matter on which the image is formed is provided with scratch resistance and plasticizer resistance. It is possible to prevent tailing during transfer of the transferable protective layer 20 and kickback during storage. Further, it is excellent in transferability onto a printed matter on which an image is formed, that is, adhesion to the printed matter. Although the exact mechanism which produces said effect by including both the 1st polyester resin and the 2nd polyester resin is not necessarily clear at present, the glass transition temperature (Tg) is 50 degreeC or more, and several The first polyester resin having an average molecular weight (Mn) of less than 6000 plays a role in preventing the occurrence of tailing and improving transferability, has a glass transition temperature (Tg) of 50 ° C. or higher, and has a number average molecular weight ( It is presumed that the second polyester resin having a Mn) of 10,000 or more and 25,000 or less plays a role of improving scratch resistance and plasticizer resistance and preventing back.

  In the present specification, the back means, for example, that the transferable protective layer 20 and the transferable dye layer are provided in the surface order on one surface of the substrate 1 and provided on the other surface of the substrate 1. Protective layer having a back layer When the transfer sheet is rolled and stored, the transferable protective layer when the dye kicked (transferred) from the transfer dye layer to the back layer is rewound after the winding process. Refers to the phenomenon of re-migration.

  Further, in the present specification, the tailing means that, at the time of transfer of the transferable protective layer, a portion of the transferable protective layer that is not desired to be transferred is dragged to a portion of the transferable protective layer that is desired to be transferred, and the card base material or the like. This phenomenon is a phenomenon in which a portion that is transferred onto the transfer body and remains on the transfer body is generated, in other words, a phenomenon in which a transferable protective layer exists in a portion that protrudes from the transfer body.

  Even when a polyester resin having a number average molecular weight (Mn) of less than 6000 and a polyester resin having a number average molecular weight (Mn) of 10,000 to 25,000 are used in combination, the glass transition temperature ( When Tg) is less than 50 ° C., the desired effect cannot be exhibited. Therefore, in the present invention, the glass transition temperatures (Tg) of the first polyester resin and the second polyester resin are both defined to be 50 ° C. or higher.

  The first polyester resin has only to satisfy the requirement that the glass transition temperature (Tg) is 50 ° C. or higher and the number average molecular weight (Mn) is less than 6000. The suppression effect is high. On the other hand, as the number average molecular weight (Mn) is less than 3000, there is a concern about deterioration of scratch resistance and plasticizer resistance, and the first polyester resin having a number average molecular weight (Mn) of less than 3000 is used alone. In such a case, the scratch resistance and plasticizer resistance tend to decrease. Therefore, in view of this point, when the first polyester resin is used alone, it is preferable to use a resin having a number average molecular weight (Mn) of 3000 or more.

  As described above, the smaller the number average molecular weight of the first polyester resin, the higher the effect of suppressing the occurrence of tailing. Therefore, as the first polyester resin, the number average molecular weight (Mn) is 3000 or more and less than 6000. By using together those having a number average molecular weight (Mn) of less than 3000, it is possible to further improve the effect of suppressing the occurrence of tailing while ensuring the effect of improving scratch resistance and plasticizer resistance. it can. There is no particular limitation on the blending ratio in this case, and the blending ratio may be appropriately blended in consideration of the desired degree of tailing suppression effect and the degree of scratch resistance and plasticizer resistance. For example, in the case where two or more kinds of first polyester resins having different number average molecular weights (Mn) are used, when the main effect is to further suppress the occurrence of tailing, the total mass of the first polyester resin On the other hand, it is preferable that the content of the first polyester resin having a number average molecular weight (Mn) of less than 3000 is large. On the other hand, when the main purpose is to further improve the scratch resistance and plasticizer resistance, It is preferable that the content of the first polyester resin having an average molecular weight (Mn) of 3000 or more and less than 6000 is large.

  The total mass of the first polyester resin and the second polyester resin is preferably in the range of 50 to 100% by mass with respect to the total solid content of the transferable protective layer 20.

  Further, the content of the first polyester resin and the second polyester resin in the transferable protective layer 20 is not particularly limited, but relative to the total mass of the first polyester resin and the second polyester resin, When the content of the first polyester resin is less than 10% by mass, the effect of suppressing the occurrence of tailing tends to be reduced, and when the content of the first polyester resin exceeds 35% by mass, The content of the second polyester resin tends to decrease, and the plasticizer resistance and scratch resistance tend to deteriorate. Therefore, considering this point, the content of the first polyester resin is preferably 10% by mass or more and 35% by mass or less with respect to the total mass of the first polyester resin and the second polyester resin. It is particularly preferable that the content is not less than 30% by mass and not more than 30% by mass. By setting it within this range, particularly excellent scratch resistance, plasticizer resistance and transferability can be exhibited, and the occurrence of tailing and back can be effectively prevented.

  In addition to the first polyester resin and the second polyester resin, which are essential components described above, other components can be added to the transferable protective layer 20 as necessary. Examples of other components include an ultraviolet absorber, an antioxidant, a fluorescent brightening agent, an inorganic or organic filler component, a surfactant, and a release agent.

  The transferable protective layer 20 containing the first polyester resin and the second polyester resin is prepared by dispersing the first polyester resin, the second polyester resin, and other components added as necessary in an appropriate solvent. Alternatively, a dissolved coating solution for a transferable protective layer is prepared, and this coating solution is applied onto the substrate 1 using a known means such as a gravure printing method, a screen printing method, a reverse roll coating method using a gravure plate, or the like. It can be formed by coating and drying.

  The transferable protective layer 20 described above may have a single-layer structure including a first polyester resin and a second polyester resin, as shown in FIG. 1. As shown in FIG. A laminated structure having a layer containing a polyester resin and a second polyester resin may be used.

<Single layer transferable protective layer>
When the transferable protective layer 20 has a single-layer structure, the layer containing the first polyester resin and the second polyester resin on the outermost surface of the printed product when the transferable protective layer 20 is transferred onto the printed product. Will be located. As described above, the layer containing the first polyester resin and the second polyester resin is excellent in scratch resistance and plasticizer resistance. Therefore, even if the transferable protective layer 20 has a single layer structure, Physical durability and plasticizer resistance can be imparted. Further, the transferable protective layer 20 can be satisfactorily transferred onto the printed material while preventing the occurrence of tailing, and the back can be prevented from being generated when the protective layer transfer sheet is stored.

  In this case, the printed matter on which the image is formed and the layer containing the first polyester resin and the second polyester resin are in direct contact with each other, but as described above, the first polyester resin and the first polyester resin are in contact with each other. Since the layer containing the polyester resin 2 is excellent in plasticizer resistance, the dye contained in the image can be prevented from transferring to the layer, and the image is not blurred. Further, the migration of the dye does not soften the layer and the plasticizer resistance does not deteriorate.

Although transferable protective layer 20 is not particularly limited for the thickness of the transferable protective layer 20 when a single layer structure, is preferably 0.5g / m ² ~10g / m ² approximately, 1 g / m ² ~ More preferably, it is about 5 g / m ² .

(Release layer)
When the transferable protective layer 20 has a single layer structure, the releasability of the transferable protective layer 20 is improved between the substrate 1 and the transferable protective layer 20 as shown in FIG. It is preferable to provide a release layer 3 for this purpose. The release layer 3 is an arbitrary layer in the protective layer transfer sheet 10 of the present invention, and is a layer remaining on the substrate 1 side when the transferable protective layer 20 is transferred. Examples of the resin forming the release layer 3 include waxes, silicone wax, silicone resin, silicone-modified resin, fluorine resin, fluorine-modified resin, polyvinyl alcohol, acrylic resin, heat-crosslinkable epoxy-amino resin, and heat-crosslinkability. Examples include alkyd-amino resins. Further, the release layer may be composed of one kind of resin or may be composed of two or more kinds of resins. The release layer may be formed by using a cross-linking agent such as an isocyanate compound, a catalyst such as a tin-based catalyst, and an aluminum-based catalyst in addition to the releasable resin. The thickness of the release layer 3 is generally about 0.5 μm to 5 μm. The release layer is formed by dissolving or dispersing the resin in a suitable solvent to prepare a release layer coating solution, which is then applied to the substrate 1 by a gravure printing method, a screen printing method or a gravure plate. It can be formed by coating and drying by a conventionally known means such as a reverse coating method using a bismuth.

<Transferable protective layer with laminated structure>
As shown in FIG. 2, when the transferable protective layer 20 has a laminated structure, the layer 20 </ b> A closest to the substrate 1 among the layers constituting the transferable protective layer 20 serves as the printable protective layer 20. When transferred to the top, the transferable protective layer 20 is positioned on the outermost surface of the transferred printed material, and the layer 20B farthest from the substrate 1 is a layer in direct contact with the image of the printed material.

  The layer containing the first polyester resin and the second polyester resin may be any of the layers constituting the transferable protective layer 20, for example, the first polyester resin and the second polyester resin. The layer 20B farthest from the substrate 1 may be the layer 20B, the layer 20A closest to the substrate 1, or any other layer. Moreover, the layer containing 1st polyester resin and 2nd polyester resin may be sufficient as two or more layers among the layers which comprise the transferable protective layer 20. FIG.

  The layer 20B farthest from the substrate 1, that is, the layer 20B that is in direct contact with the image of the printed material when the transferable protective layer 20 is transferred is a layer other than the layer containing the first polyester resin and the second polyester resin. In this case, the dye of the image shifts to a layer that is in direct contact with the printed matter, and the image is blurred. In addition, when the dye is transferred, the layer that is in direct contact with the printed matter is softened, which may cause a further decrease in plasticizer resistance.

  Considering this point, it is preferable that the layer 20B farthest from the substrate 1 in the transferable protective layer 20 having a laminated structure is a layer containing the first polyester resin and the second polyester resin. That is, the layer that functions as an adhesive layer is preferably a layer including the first polyester resin and the second polyester resin. With this configuration, it is possible to prevent the dye of the image from being transferred to the layer that is in direct contact with the printed material, and it is possible to prevent bleeding from occurring in the image. Further, since the layer containing the first polyester resin and the second polyester resin is excellent in transferability as described above, the transferable protective layer 20 can be transferred and transferred satisfactorily on the printed matter on which the image is formed. be able to. Furthermore, even if the plasticizer resistance of the layer located on the outermost surface of the printed product after the transferable protective layer 20 is transferred is low, the layer containing the first polyester resin and the second polyester resin The migration of the plasticizer component can be stopped.

  As a method for forming the layer including the first polyester resin and the second polyester resin constituting the transferable protective layer 20 having a laminated structure, the same method as the transferable protective layer 20 having the single-layer structure described above is employed. The description here is omitted.

(Peeling layer)
When the layer 20B farthest from the base material 1 among the layers constituting the transferable protective layer 20 is a layer containing the first polyester resin and the second polyester resin, the layer 20A closest to the base material 1 is A layer excellent in releasability from the substrate 1 and physical durability, for example, a layer generally referred to as a release layer is preferable. According to this configuration, the plasticizer resistance can be further improved by the synergistic effect of the release layer and the layer containing the first polyester resin and the second polyester resin, and the occurrence of back is more effectively prevented. can do. Hereinafter, an example of a preferable release layer will be described.

  Preferable release layers include ethylene-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate copolymer resin, maleic acid-modified vinyl chloride-vinyl acetate copolymer resin, polyamide resin, polyester resin, polyethylene resin, ethylene-isobutyl acrylate copolymer. Polymer resins, butyral resins, polyvinyl acetate and its copolymer resins, ionomer resins, acid-modified polyolefin resins, acrylic and methacrylic (meth) acrylic resins, acrylic ester resins, ethylene (meth) Acrylic acid copolymer, ethylene / (meth) acrylic acid ester copolymer, polymethyl methacrylate resin, cellulose resin, polyvinyl ether resin, polyurethane resin, polycarbonate resin, polypropylene resin, epoxy resin, phenol resin, Nyl resin, maleic acid resin, alkyd resin, polyethylene oxide resin, urea resin, melamine resin, melamine alkyd resin, silicone resin, rubber resin, styrene butadiene styrene block copolymer (SBS), styrene isoprene styrene block copolymer Examples thereof include thermoplastic resins such as coalescence (SIS), styrene ethylene butylene styrene block copolymer (SEBS), and styrene ethylene propylene styrene block copolymer (SEPS). These resins may be used alone or in combination of two or more. Among them, the resin mainly composed of an acrylic resin is excellent in transparency and gloss, and also excellent in scratch resistance and plasticizer resistance. Therefore, the first polyester resin and the second polyester resin described above are used. Further improvement in plasticizer resistance is expected due to the synergistic effect with the layer containing.

  Moreover, it is more preferable that the release layer contains an ultraviolet absorber. According to the release layer containing the ultraviolet absorber, it is possible to improve the light resistance, weather resistance, and the like of the image of the printed material covered with the transferable protective layer 20 after the transferable protective layer 20 is transferred. Examples of the ultraviolet absorber include salicylate-based, benzophenone-based, benzotriazole-based, triazine-based, substituted acrylonitrile-based, nickel chelate-based, hindered amine-based and the like, which are conventionally known organic ultraviolet absorbers. In addition, for example, polymers having addition polymerizable double bonds such as vinyl groups, acryloyl groups, and methacryloyl groups, or alcoholic hydroxyl groups, amino groups, carboxyl groups, epoxy groups, isocyanate groups, etc., are introduced into these ultraviolet absorbers. The material is a UV-absorbing resin, and the adhesive layer can be constituted from this UV-absorbing resin.

  The method for forming the release layer is not particularly limited, and the resin described above is added to an appropriate solvent, and this is dissolved or dispersed in an appropriate solvent to prepare a coating solution. Can be formed by applying and drying on the substrate 1 using a known means such as a gravure printing method, a screen printing method, or a reverse roll coating method using a gravure plate. Although there is no limitation in particular about the thickness of a peeling layer, about 0.8 micrometer-10 micrometers are preferable and about 0.8 micrometer-1 micrometer are more preferable.

  Moreover, you may provide an additional layer, for example, an intermediate | middle layer, between the peeling layer demonstrated above and the layer containing 1st polyester resin and 2nd polyester resin. As the intermediate layer, a cellulose-based resin such as cellulose acetate butyrate (CAB) resin can be preferably used.

(Back layer)
Also, as shown in FIGS. 1 and 2, the back layer 5 may be provided on the surface of the substrate 1 opposite to the side on which the transferable protective layer 20 is provided. The back layer 5 is an arbitrary layer in the protective layer transfer sheet 10 of the present invention. By providing the back layer 5, the thermal head can be improved in slidability and sticking can be prevented.

  The back layer 5 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 is not particularly limited as long as it is a thermoplastic resin binder having heat resistance. Examples of such a thermoplastic resin binder include acrylic resins, polyester resins, styrene-maleic acid copolymers, polyimide resins, and polyamides. Examples include resins, polyamideimide resins, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate, vinylidene fluoride resin, nylon, polyvinyl carbazole, chlorinated rubber, cyclized rubber, and polyvinyl alcohol. These resins have a glass transition point of 60 ° C. or higher, or a compound having two or more amino groups or a diisocyanate or triisocyanate added to a thermoplastic resin having an OH group or a COOH group to be slightly crosslinked and cured. What was caused is preferable.

  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 to act, and those that are useful as solids, such as fluororesin or inorganic powder. In addition to these lubricants or thermal release agents, other release agents such as fluorine-containing resin powder, guanamine resin powder and wood powder can be used in combination. High effect is obtained.

The composition for forming the back layer 5 is not particularly limited, but 10 parts by mass to 100 parts by mass of a substance that acts as a lubricant or a thermal release agent is used for 100 parts by mass of the thermoplastic resin binder. It is preferable that they are blended in proportions. Further, the back layer 5 is not particularly limited, but for example, the base layer is formed by kneading with an appropriate solvent to form an ink, and coating methods such as a roll coating method, a gravure coating method, a screen coating method, and a fountain coating method. It can be carried out by coating and drying on the surface opposite to the transferable protective layer 20 of 1. Is not particularly limited but 0.01g / m ² ~2.0g / m ² about also the thickness of the back layer 5 is common, is preferably 0.1g / m ² ~1.0g / m ² .

(Heat transferable color material layer)
In the protective layer transfer sheet of the present invention, a transferable protective layer 20 and a heat transferable color material layer (not shown) can be formed on the same substrate 1 in the order of frames. As a result, the thermal transfer colorant layer and the protective layer can be transferred with one head of the thermal transfer printer, and it is not necessary to provide a plurality of units for supplying and winding the thermal transfer sheet. And the printer transport system is not complicated.

  The heat transferable color material layer may be either a color material layer made of heat-meltable ink or a color material layer containing a sublimable dye. The heat-meltable ink is composed of a colorant and a vehicle, and various additives are added as necessary. As the colorant, among organic or inorganic pigments or dyes, those having a color density required as a recording material and not discolored by light, heat, temperature or the like are preferable. In addition, a substance that develops color when heated or a substance that develops color when in contact with a substance applied to the transfer target can also be used. In addition to cyan, magenta, yellow, black and the like, various colorants can be used as the colorant.

The vehicle is mainly composed of a wax, and in addition, a mixture of a wax and a drying oil, resin, mineral oil, cellulose, rubber derivatives, or the like is used. The heat transferable color material layer made of heat meltable ink may contain a heat conductive material in order to give good heat conductivity and melt transferability. Examples of such a heat conductive material include carbonaceous materials such as carbon black, aluminum, copper, tin oxide, and molybdenum disulfide. Examples of the method for forming the heat transferable color material layer on the substrate 1 using the above hot melt ink include known methods such as hot melt coating, hot lacquer coating, gravure coating, gravure reverse coating, and roll coating. It is done. The coating amount of the heat transferable color material layer made of a heat-meltable ink can be appropriately determined in consideration of the required printing density, heat sensitivity, etc., and is usually 0.1 g / m ^{2 to} 30 g at the time of drying. / M ² .

  The heat transferable color material layer containing a sublimable dye is obtained by dispersing or dissolving a heat transferable dye in a binder resin. As the binder resin, those having a moderate affinity with the dye, and those in which the dye in the binder resin is sublimated (heat transferred) by heating with a thermal head, and transferred to the transfer target are good. Use resin that does not transfer. Examples of the resin used as such a binder resin include cellulose resins such as ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose nitrate, cellulose acetate, and acetic acid / butyric acid cellulose, polyvinyl alcohol, and polyacetic acid. Examples thereof include vinyl resins such as vinyl, polyvinyl butyral, polyacrylamide, and polyvinyl pyrrolidone, polyester, and polyamide.

  The proportion of the dye contained in the heat transferable color material layer varies depending on the dye sublimation (melting) temperature, dyeing property, etc., but is preferably 30 parts by mass or more, more preferably 100 parts by mass of the binder resin. Is 30 to 300 parts by weight. When the amount of the dye is less than 30 parts by mass, the printing density and thermal sensitivity are low, and when it exceeds 300 parts by mass, the storage stability and the adhesion of the heat transferable colorant layer to the substrate 1 are lowered.

  The dye used in the heat transferable color material layer is a dye which melts, diffuses or sublimates by heat and moves to the transfer target, and a disperse dye is particularly preferably used. The dye is selected in consideration of sublimation (melting) property, hue, light resistance, solubility in a binder resin, and the like. Examples of these dyes include methine series such as diarylmethane series, triarylmethane series, thiazole series, and merocyanine, indoaniline, acetophenone azomethine, pyrazoloazomethine, imidazole azomethine, imidazoazomethine, and azomethine series represented by pyridone azomethine. , Xanthene series, oxazine series, dicyanostyrene, cyanomethylene series represented by tricyanostyrene, thiazine series, azine series, acridine series, benzeneazo series, pyridoneazo, thiophenazo, isothiazole azo, pyrrole azo, pyrazole azo, imidazole azo, Azos such as thiadiazole azo, triazole azo, disazo, spiropyran, indolinospiropyran, fluoran, rhodamine lactam, naphthoquinone, anthraquino Systems include the quinophthalone like.

The heat transferable color material layer, which is a dye layer, can be provided on the substrate 1 by a known method. For example, a dye and binder resin are dissolved or dispersed together with a solvent to prepare an ink composition for a heat transferable color material layer, which is provided on the substrate 1 by a method appropriately selected from known printing methods or coating methods. It ’s fine. The coating amount of the dye layer, dry with ^{0.2g / m 2 ~5.0g / m 2} , and preferably from the thickness of ^{0.4g / m 2 ~2.0g / m 2} .

  The heat transferable color material layer described above may be provided with one heat transfer type color material layer on the substrate 1, and two or more different color hues of the heat transfer color material layer are sequentially arranged on the substrate 1. It is good also as forming in. In particular, a yellow color material layer, a magenta color material layer, and a cyan color material layer are sequentially formed on the substrate 1 as a heat transferable color material layer containing a sublimation dye, thereby achieving high quality comparable to a full color photographic image. It is preferable to form a clear image in which a thermal transfer image is formed and a deviation in print length is prevented between hues in a full color thermal transfer image. In the case of a black character or pattern thermal transfer image, it is possible to obtain black by overlaying the above three colors of the yellow color material layer, magenta color material layer, and cyan color material layer of the dye layer. It is preferable that a color material layer made of black heat-meltable ink using a black colorant is added to the base sheet. As a result, a clear image having a high black density can be obtained.

(Transfer method)
When the protective layer transfer sheet 10 of the present invention is used to transfer the transferable protective layer 20 (thermal transferable color material layer if necessary) by thermal transfer to form an image on the transfer target, the thermal transfer printer is sublimated. The transfer conditions may be set separately such as transfer, hot melt transfer, and protective layer transfer, or the printing energy may be appropriately adjusted with a common printer. Moreover, it is not specifically limited as a heating means, In addition, it is good also as performing transfer using a hot plate, a hot stamper, a hot roll, a line heater, an iron, etc.

  The protective layer transfer sheet 10 of the present invention has been described in detail above, but the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

  Next, an Example is given and this invention is demonstrated further more concretely. “Part” in the text is based on mass unless otherwise specified.

Example 1
A polyethylene terephthalate film having a thickness of 5 μm was used as a base material, and a transfer layer 1 having a composition described below was applied thereon so that the coating amount when dried was 1.0 g / m ^2. A release layer was formed. Next, an adhesive layer coating liquid 1 having the following composition was applied on the release layer so that the coating amount when dried was 1.6 g / m ² to form an adhesive layer constituting a transferable protective layer. Further, a back layer coating liquid having the following composition is applied on a surface different from the surface on which the transferable protective layer of the substrate is formed so that the coating amount when dried is 1.0 g / m ^2. By forming, the protective layer transfer sheet of Example 1 was obtained.

<Peeling layer coating solution 1>
・ Acrylic resin 20 parts (Dianar BR-87, manufactured by Mitsubishi Rayon Co., Ltd.)
・ Toluene 40 parts ・ Methyl ethyl ketone 40 parts

<Coating liquid 1 for adhesive layer>
Polyester resin (number average molecular weight: 3000, Tg: 53 ° C.) 1.7 parts (Byron 220 manufactured by Toyobo Co., Ltd.)
Polyester resin (number average molecular weight: 23000, Tg: 67 ° C.) 15.3 parts (Byron 270 manufactured by Toyobo Co., Ltd.)
・ Ultraviolet absorber copolymer resin 15 parts (UBA-635L manufactured by BASF Japan)
-Toluene / methyl ethyl ketone (mass ratio 1: 1) 68 parts

(Back layer coating liquid)
・ 2.0 parts of polyvinyl butyral resin (SREC BX-1 Sekisui Chemical Co., Ltd.)
・ Phosphate surfactant 1.3 parts (Pricesurf A208N Daiichi Kogyo Seiyaku Co., Ltd.)
・ Talc 0.3 part (Microace P-3 Nippon Talc Industry Co., Ltd.)
・ 9.2 parts of polyisocyanate (Bernock D750-45 Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 43.6 parts ・ Toluene 43.6 parts

(Example 2)
A protective layer transfer sheet of Example 2 was obtained in the same manner as Example 1 except that the adhesive layer coating solution 2 having the following composition was used instead of the adhesive layer coating solution 1.

<Coating liquid 2 for adhesive layer>
Polyester resin (number average molecular weight: 3000, Tg: 53 ° C.) 3.4 parts (byron 220 manufactured by Toyobo Co., Ltd.)
Polyester resin (number average molecular weight: 23000, Tg: 67 ° C.) 13.6 parts (Byron 270 manufactured by Toyobo Co., Ltd.)
・ Ultraviolet absorber copolymer resin 15 parts (UBA-635L manufactured by BASF Japan)
-Toluene / methyl ethyl ketone (mass ratio 1: 1) 68 parts

(Example 3)
A protective layer transfer sheet of Example 3 was obtained in the same manner as Example 1 except that the adhesive layer coating solution 3 having the following composition was used instead of the adhesive layer coating solution 1.

<Coating liquid 3 for adhesive layer>
Polyester resin (number average molecular weight: 3000, Tg: 53 ° C.) 5.1 parts (Byron 220 manufactured by Toyobo Co., Ltd.)
Polyester resin (number average molecular weight: 23000, Tg: 67 ° C.) 11.9 parts (Byron 270 manufactured by Toyobo Co., Ltd.)
・ Ultraviolet absorber copolymer resin 15 parts (UBA-635L manufactured by BASF Japan)
-Toluene / methyl ethyl ketone (mass ratio 1: 1) 68 parts

( Reference Example 1 )
A protective layer transfer sheet of Reference Example 1 was obtained in the same manner as Example 1 except that the adhesive layer coating solution 4 having the following composition was used instead of the adhesive layer coating solution 1 .

<Coating liquid 4 for adhesive layer>
Polyester resin (number average molecular weight: 3000, Tg: 53 ° C.) 6.8 parts (Byron 220 manufactured by Toyobo Co., Ltd.)
Polyester resin (number average molecular weight: 23000, Tg: 67 ° C.) 10.2 parts (Byron 270 manufactured by Toyobo Co., Ltd.)
・ Ultraviolet absorber copolymer resin 15 parts (UBA-635L manufactured by BASF Japan)
-Toluene / methyl ethyl ketone (mass ratio 1: 1) 68 parts

(Example 5)
A release layer coating solution having the following composition is applied onto a substrate so that the coating amount upon drying is 1.0 g / m ² , and then the release layer is formed on the substrate. On top of this, in place of the release layer coating liquid 1, a release layer coating liquid 2 having the following composition is used, and in place of the adhesive layer coating liquid 1, the adhesive layer coating liquid 3 having the above composition is used. Then, a protective layer transfer sheet of Example 5 was obtained in the same manner as in Example 1 except that a release layer and an adhesive layer were formed.

<Release layer coating solution>
・ Silicone-modified acrylic resin 45.7 parts (Cell Top 226, manufactured by Daicel Chemical Industries, Ltd.)
・ 8.5 parts of aluminum catalyst (Cell Top CAT-A, manufactured by Daicel Chemical Industries, Ltd.)
・ Methyl ethyl ketone 22.9 parts ・ Toluene 22.9 parts

<Peeling layer coating solution 2>
・ 20 parts of vinyl chloride-vinyl acetate copolymer (Solvine CNL, manufactured by Nissin Chemical Industry Co., Ltd.)
・ Toluene 40 parts ・ Methyl ethyl ketone 40 parts

( Reference Example 2 )
A protective layer transfer sheet of Reference Example 2 was obtained in the same manner as in Example 1 except that the adhesive layer coating solution 5 having the following composition was used instead of the adhesive layer coating solution 1.

<Coating liquid 5 for adhesive layer>
Polyester resin (number average molecular weight: 3000, Tg: 53 ° C.) 5.1 parts (Byron 220 manufactured by Toyobo Co., Ltd.)
Polyester resin (number average molecular weight: 18000, Tg: 68 ° C.) 11.9 parts (Byron 280 manufactured by Toyobo Co., Ltd.)
・ Ultraviolet absorber copolymer resin 15 parts (UBA-635L manufactured by BASF Japan)
-Toluene / methyl ethyl ketone (mass ratio 1: 1) 68 parts

(Example 7)
All except that the release layer coating solution 3 having the following composition was used instead of the release layer coating solution 1, and the adhesive layer coating solution 3 having the above composition was used instead of the adhesive layer coating solution 1. A protective layer transfer sheet of Example 7 was obtained in the same manner as Example 1.

<Peeling layer coating solution 3>
Cellulose acetate butyrate resin 20 parts (CAB381-20, manufactured by Eastman Kodak Company)
・ Toluene 40 parts ・ Methyl ethyl ketone 40 parts

(Example 8)
A protective layer transfer sheet of Example 8 was obtained in the same manner as Example 1 except that the adhesive layer coating solution 6 having the following composition was used instead of the adhesive layer coating solution 1.

<Coating liquid 6 for adhesive layer>
Polyester resin (number average molecular weight: 3000, Tg: 53 ° C.) 1.7 parts (Byron 220 manufactured by Toyobo Co., Ltd.)
Polyester resin (number average molecular weight: 23000, Tg: 67 ° C.) 15.3 parts (Byron 270 manufactured by Toyobo Co., Ltd.)
-Toluene / methyl ethyl ketone (mass ratio 1: 1) 68 parts

(Comparative Example 1)
A protective layer transfer sheet of Comparative Example 1 was obtained in the same manner as in Example 1 except that the adhesive layer coating solution A having the following composition was used instead of the adhesive layer coating solution 1.

<Coating liquid A for adhesive layer>
Polyester resin (number average molecular weight: 23000, Tg: 67 ° C.) 17 parts (Byron 270 manufactured by Toyobo Co., Ltd.)
・ Ultraviolet absorber copolymer resin 15 parts (UBA-635L manufactured by BASF Japan)
-Toluene / methyl ethyl ketone (mass ratio 1: 1) 68 parts

(Comparative Example 2)
A protective layer transfer sheet of Comparative Example 2 was obtained in the same manner as Example 1 except that the adhesive layer coating solution B having the following composition was used instead of the adhesive layer coating solution 1.

<Coating liquid B for adhesive layer>
Polyester resin (number average molecular weight: 3000, Tg: 53 ° C.) 17 parts (byron 220 manufactured by Toyobo Co., Ltd.)
・ Ultraviolet absorber copolymer resin 15 parts (UBA-635L manufactured by BASF Japan)
-Toluene / methyl ethyl ketone (mass ratio 1: 1) 68 parts

(Comparative Example 3)
A protective layer transfer sheet of Comparative Example 3 was obtained in the same manner as Example 1, except that the adhesive layer coating solution C having the following composition was used instead of the adhesive layer coating solution 1.

<Coating liquid C for adhesive layer>
Polyester resin (number average molecular weight: 23000, Tg: 67 ° C.) 11.9 parts (Byron 270 manufactured by Toyobo Co., Ltd.)
Polyester resin (number average molecular weight: 8000, Tg: 65 ° C.) 5.1 parts (Byron 226 manufactured by Toyobo Co., Ltd.)
・ Ultraviolet absorber copolymer resin 15 parts (UBA-635L manufactured by BASF Japan)
-Toluene / methyl ethyl ketone (mass ratio 1: 1) 68 parts

(Comparative Example 4)
A protective layer transfer sheet of Comparative Example 4 was obtained in the same manner as in Example 1 except that the adhesive layer coating solution D having the following composition was used instead of the adhesive layer coating solution 1.

<Coating liquid D for adhesive layer>
Polyester resin (number average molecular weight: 3000, Tg: 53 ° C.) 5.1 parts (Byron 220 manufactured by Toyobo Co., Ltd.)
Polyester resin (number average molecular weight: 16000, Tg: 47 ° C.) 11.9 parts (Byron 600 manufactured by Toyobo Co., Ltd.)
・ Ultraviolet absorber copolymer resin 15 parts (UBA-635L manufactured by BASF Japan)
-Toluene / methyl ethyl ketone (mass ratio 1: 1) 68 parts

(Formation of thermal transfer image receiving sheet and image)
Using a card base material having the following composition, each dye is transferred onto the card base material according to each image information of yellow, magenta and cyan obtained by color-separating the face photograph using the following thermal printer. To form a full-color photographic image. As the yellow, magenta and cyan dyes, thermal transfer sheets for printers (HDP-600) manufactured by HID were used.

<Material composition of card base>
-100 parts of polyvinyl chloride compound (degree of polymerization 800) (contains about 10% of additives such as stabilizers)
・ White pigment (titanium oxide) 10 parts ・ Plasticizer (DOP) 0.5 parts

<Thermal printer>
Gradation control system; Multi-pulse system thermal head that can vary the number of divided pulses from 0 to 255 with a pulse length that equally divides one line period into 256; KEE-57-12GAN2-STA (manufactured by Kyocera Corporation)
Heating element average resistance value: 3303 (Ω)
Main scanning direction printing density; 300 dpi
Sub-scanning direction print density; 300 dpi
Printing voltage: 18 (V)
1 line cycle; 3.0 (msec.)
Printing start temperature: 35 (℃)
Pulse duty: 85%

(Transfer of transferable protective layer)
Using the protective layer transfer sheets of Examples 1 to 3 , 5 and 7, 8, Comparative Examples 1 to 4, Reference Examples 1 and 2 , and on the PVC card on which the above full-color photographic image was formed under the following conditions The transferable protective layer was transferred to a printed product of Examples 1 to 3, 5 , 7, 8, Comparative Examples 1 to 4, Reference Examples 1 and 2 to which the transferable protective layer was transferred. In each of the examples, comparative examples, and reference examples, transfer of the transferable protective layer was performed with the above-described thermal printer at a gradation value of 230.

(Abrasion resistance evaluation)
The prints of Examples 1 to 3 , 5 , 7, 8, Comparative Examples 1 to 4, Reference Examples 1 and 2 obtained by the transfer of the transferable protective layer were subjected to a scratch resistance tester (rotary abrasion manufactured by Toyo Seiki Co., Ltd.). Using a tester, the abrasion wheel CS-10F was subjected to an abrasion test of 500 rotations on the protective layer at a load of 500 g, and the scratch resistance of the transferable protective layer was visually evaluated according to the following criteria. Table 1 shows the evaluation results of the scratch resistance.

<Evaluation criteria>
○: Almost no effect on printed matter.
Δ: An effect is seen on the printed matter, but it is a level that does not cause a problem in use.
X: Prints have obvious scratches.

(Evaluation of plasticizer resistance)
A plasticized soft vinyl chloride sheet (Mitsubishi Chemical Co., Ltd. Altron # 480, thickness 400 μm) and the protective layer transfer surface of the printed material are overlapped and stored at 80 ° C. for 8 hours under a load of 24 gf / cm ^2. Then, the deterioration state of the image by the plasticizer was visually observed, and the plasticizer resistance of the protective layer was evaluated according to the following criteria. The evaluation results of the plasticizer resistance are also shown in Table 1.

<Evaluation criteria>
◎ ・ ・ ・ No dye transfer.
○: There is almost no migration of the dye.
Δ: Dye migration can be confirmed to some extent, but at a level that does not cause any problems in use.
X: Dye is transferred over almost the entire surface.

(Tailing evaluation)
The remaining state of the transferable protective layer (adhesive layer) in the transfer of the transferable protective layer was visually confirmed, and tailing evaluation was performed according to the following evaluation criteria. The evaluation results are also shown in Table 1.

<Evaluation criteria>
○: Little tailing occurs (less than 1 mm).
Δ: Some tailing (1 mm or more and less than 2 mm) is at a level where there is no problem in use.
X: A considerable amount of tailing occurs (2 mm or more).

(Back evaluation)
The magenta part of the ink ribbon of Canon color ink / paper set KP-36IP (trade name) and the back layer are opposed to each other and a load of 20 kgf / cm ² is applied to the ink ribbon at 40 ° C. and humidity of 90%. And stored for 96 hours to transfer (kick) the dye to the back layer. In addition, the back layer used for the kick of dye used the same thing as the back layer used by said each Example , a comparative example , and a reference example .

The back layer having the dye kicked by the above method and the adhesive layer of the protective layer transfer sheet of each example , comparative example , and reference example were overlaid, and a constant load compression tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.) The sample was stored under an environment of 60 ° C. and 20% humidity for 24 hours under a load of 20 kgf / cm ² to forcibly retransfer (back) the dye. Thereafter, the adhesive layer on which the dye re-transferred (backed) and the image receiving surface of the image receiving paper were superposed, and using a laminating tester (Lamipacker LPD2305PRO, manufactured by Fuji Pla Co., Ltd.) at 105 ° C., 4 mm / sec / line. The transferable protective layer was transferred. Subsequently, the transferable protective layer was peeled off from the image receiving paper, and the hue of the transfer part was measured using GRETAG Spectrolino (D65 light source, viewing angle 2 °) manufactured by Gretag, and evaluated based on the following criteria. As the image receiving paper, a color ink / paper set KP-36IP (trade name) manufactured by Canon Inc. was used.

(Color difference calculation formula)
ΔE ^* = ((difference between L ^* values before and after facing) ² + (difference between a ^* values before and after facing) ² + (difference between b ^* values before and after facing) ² ) ^1/2

(Evaluation criteria)
○: Color difference ΔE ^* between the transfer product transferred from the unpreserved protective layer and the transfer product transferred from the back transferable protective layer is less than 1.5 Δ: The transfer product transferred from the non-preserved protective layer and the back The color difference ΔE ^* of the transferred product obtained by transferring the transferred protective protective layer is 1.5 or more and less than 3.5 ×: the transferred product obtained by transferring the unprotected protective layer and the transferred product obtained by transferring the backed protective protective layer Color difference ΔE ^* of 3.5 or more

(Transferability evaluation)
A monocolor image was formed on the card substrate used for the transfer of the transferable protective layer using the thermal printer. Next, using the protective transfer sheets of Examples 1 to 3 , 5 , 7, 8, Comparative Examples 1 to 4, Reference Examples 1 and 2 , up to 255 to 130 gradations on a PVC card on which a monocolor image was formed. After transferring the pattern image in which the gradation was changed by 25 gradations, it was judged visually by which gradation it was transferred, and the adhesiveness was evaluated based on the following evaluation criteria. In addition, it can be said that adhesiveness is so favorable that a transferable protective layer transfers with low gradation. The adhesive evaluation results are also shown in Table 1.

<Evaluation criteria>
A: The transferable protective layer was transferred with 255 to 130 gradations.
○: The transferable protective layer was transferred at a gradation of 255 to 155.
Δ: The transferable protective layer was transferred with 255 to 180 gradations.
X: The transferable protective layer was transferred with 255 to 205 gradations.

  As is clear from the above results, according to the protective layer transfer sheet of the example provided with the transferable protective layer containing the first polyester resin and the second polyester resin, the scratch resistance evaluation, the plasticizer resistance evaluation, Stable evaluations could be obtained in all evaluations of tailing evaluation, back evaluation and transferability evaluation. On the other hand, the protective layer transfer sheet of the comparative example that does not include both the first polyester resin and the second polyester resin or one of them does not satisfy all the evaluations. Sex is obvious.

DESCRIPTION OF SYMBOLS 10 Protective layer transfer sheet 1 Base material 3 Release layer 5 Back layer 20 Transferable protective layer

Claims (3)

A protective layer transfer sheet having a base material and a transferable protective layer that is detachably provided on the base material,
The transferable protective layer is
(A) a first polyester resin having a glass transition temperature (Tg) of 50 ° C. or higher and a number average molecular weight (Mn) of less than 6000;
(B) a second polyester resin having a glass transition temperature (Tg) of 50 ° C. or higher and a number average molecular weight (Mn) of 23,000 to 25,000,
Including
The content of the (A) first polyester resin is in the range of 10% by mass to 35% by mass with respect to the total mass of the (A) first polyester resin and the (B) second polyester resin. A protective layer transfer sheet, wherein The transferable protective layer has a configuration in which a release layer and an adhesive layer are laminated in this order from the substrate side,
2. The protective layer transfer sheet according to claim 1, wherein the adhesive layer contains the (A) first polyester resin and the (B) second polyester resin. 3.   The protective layer transfer sheet according to claim 1, wherein a release layer is provided between the base material and the transferable protective layer.

Images