JP2016060053A - Thermal transfer sheet with protective layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal transfer sheet with a protective layer having excellent long-term storage properties in a rolled-up form, free from abnormal transfer such as transfer unevenness, burr or adhesion when forming the protective layer by thermal transfer and having excellent tolerance to a printed matter.SOLUTION: A thermal transfer sheet with a protective layer includes: a thermostable lubricant layer formed on one side of a base material 1; and a thermally-transferable ink layer of three colors, yellow, magenta and cyan, and a thermally-transferable protective layer, frame-sequentially formed in a longer direction on the other side. The thermally-transferable protective layer 9 is formed by sequentially laminating a release layer 7 and an adhesion layer 8 on the other side of the base material 1. The adhesion layer 8 includes: two kinds of epoxy resin whose softening points are lower than 100°C, and 100°C or higher, respectively; urethane-modified polyester resin; and ultraviolet light absorber. The compounding ratio of the two kinds of epoxy resin is within a range of 3:7 to 7:3.SELECTED DRAWING: Figure 1

Description

  The present invention comprises a thermal transfer protective layer for partially transferring a thermal transfer sheet, in particular, a transfer image recorded on a transfer medium so that the transfer image can be protected. The present invention relates to a thermal transfer sheet with a protective layer.

  In general, a thermal transfer sheet, also called a thermal ribbon, is an ink ribbon used in a thermal transfer type printer. A thermal transfer layer is formed on one side of a substrate and a heat-resistant slipping layer (back coat on the other side). Layer). Here, the heat-sensitive transfer layer is an ink layer, and the ink is sublimated (sublimation transfer method) or melted (melt transfer method) by the heat generated by the thermal head of the printer, and transferred to the transfer target side. is there.

  Currently, among the thermal transfer systems, the sublimation transfer system can easily form full-color images with various functions of the printer, so digital camera self-prints, cards such as identification cards, amusement output, etc. It is widely used, and there is a demand for miniaturization, high speed, and low cost along with diversification of applications. In addition, prints formed by the sublimation transfer method have the disadvantage that these dyes are inherently poor in preservability and their images are also poor in preservability, so durability to the resulting prints is also required. ing. As a specific example of durability, a plasticizer in which a printed matter is stored in a vinyl chloride case containing a plasticizer or the like, and the dye forming the image does not migrate to the case side even when stored. And light resistance to prevent fading caused by sunlight and sunlight.

  In order to solve these problems, in recent years, a thermal transfer sheet with a protective layer having a plurality of thermal transfer layers provided on the same side of the substrate so as not to overlap each other and a protective layer imparting durability to the printed matter Several have been proposed. For example, in Patent Document 1, in a protective layer transfer film in which a thermal transfer resin layer is provided on a base film, the thermal transfer resin layer is sequentially formed from the base film side, a transparent resin layer, and a plasticizer-resistant resin layer. There has been proposed a protective layer transfer film comprising a laminate in which heat-adhesive resin layers are laminated in this order.

  Moreover, in patent document 2, the protective layer transfer in which the thermosetting transparent resin layer which consists of acrylic polyol resin and a hardening | curing agent, and the thermoadhesive resin layer were laminated | stacked in order on the base film as a heat transferable resin layer. A sheet has been proposed.

JP-A-7-156567 JP2008-238525A

  However, since the protective layer transfer film of Patent Document 1 is provided with a plasticizer-resistant resin layer, the cost of raw materials is increased, and further, a process for forming the plasticizer-resistant resin layer is required, and the cost is low. Cannot be made. Since the protective layer transfer sheet of Patent Document 2 uses a curing agent, the pot life of the coating liquid is short. In addition, as for the protective layer of many proposed thermal transfer sheets with a protective layer, a plurality of layers are transferred as a laminate. When only the layer is transferred, there is a concern that expected durability cannot be obtained.

  The present invention provides a thermal transfer sheet with a protective layer that is excellent in long-term storage in a winding form, has no abnormal transfer such as uneven transfer, burrs, and sticking when a protective layer is formed by thermal transfer, and has excellent resistance to printed matter. It is intended to do.

In order to solve the above problems, the present invention employs the following configuration.
[1] A protection in which a heat-resistant slipping layer is provided on one surface of a base material, and a heat transferable ink layer of three colors, yellow, magenta, and cyan, and a heat transferable protective layer are provided in the longitudinal direction on the other surface. A thermal transfer sheet with a layer, wherein the thermal transferable protective layer is formed by sequentially laminating a release layer and an adhesive layer on the other surface of the substrate, and the adhesive layer has a softening point of less than 100 ° C. and 100 Protection comprising two types of epoxy resins at a temperature of ℃ or higher, a urethane-modified polyester resin, and an ultraviolet absorber, and a blending ratio of the two types of epoxy resins being in a range of 3 to 7 to 7 to 3 Thermal transfer sheet with layers.
[2] The thermal transfer sheet with a protective layer according to [1], wherein a blending ratio of the epoxy resin and the urethane-modified polyester resin in the adhesive layer is in a range of 9: 1 to 6: 4. [3] The thermal transfer sheet with a protective layer according to [1] or [2], wherein the ultraviolet absorber is a benzotriazole type.
[4] The amount of the ultraviolet absorber occupying in the adhesive layer is 5 to 100 parts by mass with respect to 100 parts by mass of the total resin, and any one of [1] to [3] A thermal transfer sheet with a protective layer according to Item.
[5] With the protective layer according to any one of [1] to [4], the coating amount of the adhesive layer after drying is 0.5 to 1.0 g / m ^2. Thermal transfer sheet.
[6] The release layer is made of at least an acrylic resin and a polyester resin, and the mass ratio of the polyester resin is 0.3 to 2.0 with respect to the entire resin. [1] to [5] The thermal transfer sheet with a protective layer of any one of these.

  According to the present invention, the protective layer for protecting the printed matter formed by thermal transfer has an adhesive layer composed of an epoxy resin, a urethane-modified polyester resin and an ultraviolet absorber, and the adhesive layer has a softening point of 100 ° C. Because it is composed of two types of epoxy resins with a temperature of less than 100 ° C or higher, it has excellent long-term storage in the form of winding, and there is no abnormal transfer such as uneven transfer, burrs, and sticking when forming a protective layer by thermal transfer, and printing. It is possible to provide a thermal transfer sheet with a protective layer excellent in physical resistance.

  The present invention is characterized by the difference in the softening point of the epoxy resin in the adhesive layer. For the epoxy resin having a low softening point, the adhesiveness is improved by utilizing the good thermal sensitivity, while the epoxy resin having a high softening point is used. Is responsible for improving the storage stability of the thermal transfer medium and the durability of the protective layer.

  Specifically, the blending ratio of the two types of epoxy resins having a softening point of less than 100 ° C. and 100 ° C. or more contained in the adhesive layer is in the range of 3 to 7 to 7 to 3, An excellent thermal transfer medium can be provided by making use of thermal characteristics. That is, the sensitivity at the time of thermal transfer can be improved by an epoxy resin having a relatively low heat resistance and a softening point of less than 100 ° C. On the other hand, storage stability in a wound form can be obtained with an epoxy resin having a relatively high heat resistance and a softening degree of 100 ° C. or higher. As a result, the storage stability of the thermal transfer medium, the formation of a stable printed product during thermal transfer, and a printed product with high quality and excellent durability can be obtained.

It is sectional drawing of the thermal transfer sheet with a protective layer which concerns on embodiment based on this invention.

  As shown in FIG. 1, the thermal transfer sheet with a protective layer according to one embodiment of the present invention has three colors of thermal transfer of yellow (3), magenta (4), and cyan (5) on one surface of the substrate (1). A protective layer (9) composed of a layer (6), a release layer (7), and an adhesive layer (8) is surface-sequentially arranged in the longitudinal direction, and a heat-resistant slipping layer (2) is provided on the other surface of the substrate (1). It has a provided structure.

  As the base material (1), heat resistance and strength that are not softened and deformed by heat pressure in thermal transfer are required. For example, polyester, polypropylene, cellophane, polycarbonate, cellulose acetate, polyethylene, polyvinyl chloride, polystyrene, nylon, polyimide , Synthetic resin films such as polyvinylidene chloride, polyvinyl alcohol, fluororesin, chlorinated rubber, and ionomer, and papers such as condenser paper and paraffin paper can be used alone or in combination. Among these, a polyethylene terephthalate film is preferable in view of physical properties, workability, cost, and the like. In addition, the thickness can be in the range of 2 μm to 50 μm in consideration of operability and workability, but in consideration of handling properties such as transfer suitability and workability, it is about 2 μm to 9 μm. Those are preferred.

  Moreover, in the base material (1), it is also possible to perform adhesion treatment on one side or / and both sides. As the adhesion treatment, known techniques such as corona treatment, flame treatment, ozone treatment, ultraviolet treatment, radiation treatment, roughening treatment, plasma treatment, primer treatment, etc. can be applied, and these treatments are used in combination. You can also

  Next, the heat-resistant slip layer (2) is provided on the thermal transfer recording medium on the side in contact with the thermal head for the purpose of preventing seizure of the thermal head and the thermal transfer recording medium and imparting slidability between the thermal head and the ink sheet. It is done. Conventionally known materials can be used, and binder resins such as polyvinyl butyral resin, polyvinyl acetoacetal resin, polyester resin, vinyl chloride-vinyl acetate copolymer, polyether resin, polybutadiene resin, acrylic polyol, polyurethane acrylate Polyester acrylate, polyether acrylate, epoxy acrylate, nitrocellulose resin, cellulose acetate resin, polyamide resin, polyimide resin, polyamideimide resin, polycarbonate resin, polyacrylic resin, and modified products thereof. Further, a curing agent may be used to increase heat resistance. Examples of the curing agent include isocyanates such as tolylene diisocyanate, triphenylmethane triisocyanate, tetramethylxylene diisocyanate, and derivatives thereof, but are not particularly limited. Furthermore, a functional additive imparting releasability and slipperiness, a filler, a curing agent, a solvent, and the like may be included.

The range of 0.1 to 2.0 g / m ² is appropriate for the coating amount after drying of the heat resistant slipping layer (2). Here, the coating amount after drying of the heat-resistant slipping layer (2) means the solid content remaining after the coating solution for forming the heat-resistant slipping layer is applied and dried, and the thermal transfer layer (6) described later. Similarly, the coating amount after drying and the coating amount after drying of the release layer (7) and the adhesive layer (8) also refer to the solid content remaining after the coating solution is applied and dried.

  Next, the thermal transfer layer (6) can be handled by a conventionally known one. For example, by preparing a coating solution for forming a thermal transfer layer by blending a heat transferable dye, a binder, a solvent, etc., and applying and drying the coating solution. It is formed. The thermal transfer layer (6) can be composed of a single layer of one color, or a plurality of thermal transfer layers containing dyes having different hues can be repeatedly formed on the same surface of the same substrate in the surface order. . The heat transferable dye is a dye that melts, diffuses or sublimates by heat. For example, examples of yellow components include Solvent Yellow 56, 16, 30, 93, 33, Disperse Yellow 201, 231, 33, and the like. Examples of the magenta component include C.I. I. Disperse violet 31, C.I. I. Disperse thread 60, C.I. I. Disperse violet 26, C.I. I. Solvent Red 27, or C.I. I. Solvent Red 19 etc. can be mentioned. As the cyan component, C.I. I. Disperse Blue 354, C.I. I. Solvent Blue 63, C.I. I. Solvent Blue 36, C.I. I. Solvent Blue 266, C.I. I. Disperse Blue 257 or C.I. I. Disperse Blue 24 and the like.

  As the binder contained in the thermal transfer layer (6), any conventionally known binder can be used, and is not particularly limited, but cellulose resins such as ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, cellulose acetate and the like. And vinyl resins such as polyvinyl alcohol, polyvinyl acetate, polyvinyl acetal, polyvinyl pyrrolidone, and polyacrylamide, polyester resins, styrene-acrylonitrile copolymer resins, and phenoxy resins.

  Here, the mixing ratio of the dye and binder in the thermal transfer layer (6) is preferably (dye) / (binder) = 10/100 to 300/100 on a mass basis. This is because when the ratio of (dye) / (binder) is less than 10/100, the amount of dye is too small and the color development sensitivity becomes insufficient, and a good thermal transfer image cannot be obtained, and this ratio is 300/100. If it exceeds the upper limit, the solubility of the dye in the binder is extremely lowered, so that when it becomes a thermal transfer recording medium, the storage stability is deteriorated and the dye tends to precipitate. The thermal transfer layer may contain known additives such as an isocyanate compound, a silane coupling agent, a dispersant, a viscosity modifier, and a stabilizer as long as the performance is not impaired.

  The protective layer (9) is required to have durability such as plasticizer resistance to an image formed on the transferred material by the thermal transfer layer, and at the same time, needs to be formed on the transferred material by a process called a thermal transfer method. Therefore, it is generally formed from a laminate of a plurality of layers of an adhesive layer (8) having adhesiveness to the transfer target and a release layer (7) for easily peeling from the base material at the time of thermal transfer. Is done.

  As the binder constituting the release layer (7), acrylic resins such as polymethyl methacrylate and polyethyl acrylate are preferable from the viewpoint of durability such as wear resistance and transparency, but the performance is not impaired. Styrene resin such as polystyrene and poly-α-methylstyrene, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polyvinyl acetal and other vinyl resins, polyamide resin, epoxy resin, Synthetic resins such as polyurethane resin, petroleum resin, ionomer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, cellulose derivatives such as nitrocellulose, ethyl cellulose, cellulose acetate propionate, rosin, rosin modified maleic acid Resin, ester gum, polyisobuty Ngomu, butyl rubber, styrene - butadiene rubbers, butadiene - it acrylonitrile rubber, derivatives of natural resins and synthetic rubber polychlorinated olefins such as carnauba wax, also possible to use waxes such as paraffin wax. Among them, the same polyester resin as the polyethylene terephthalate film as the base material is preferable because it can be used together with the acrylic resin because the adhesion of the release layer to the base material during non-transfer can be improved.

  The mass ratio of the polyester resin is preferably 0.3 to 2.0 of the entire resin. When the ratio of the polyester resin is less than 0.3, the release layer does not adhere to the substrate because the addition amount of the polyester resin is small. On the other hand, when the ratio of the polyester resin is more than 2.0, it is difficult to peel off in the cold state, and the ratio of the polyester resin is increased.

Furthermore, the glass transition temperature of the polyester resin to be used is preferably 40 ° C. or higher and 70 ° C. or lower. When the glass transition temperature is lower than 40 ° C., even when a polyester resin is added, the adhesion of the release layer to the substrate during non-transfer Can not increase. On the other hand, if the glass transition temperature is higher than 70 ° C., the release layer does not peel from the base material during the peeling at the cold, even if the peeling at the time of heating is possible.

The coating amount after drying of the release layer (7) is not generally limited, but is preferably in the range of 0.5 to 1.5 g / m ² .

  In the release layer (7), silicone oil, a release agent typified by phosphate ester, a slipping agent typified by wax, an ultraviolet absorber, a light stabilizer, an antioxidant, as long as the performance is not impaired. Known additives such as fluorescent brighteners and antistatic agents can be used.

  As described above, the adhesive layer (8) according to the present invention has excellent storage stability for the winding form of the thermal transfer medium of the present invention, heat transfer without abnormalities of the protective layer, and further excellent protection for printed matter. In order to form a protective layer, it is essential to include two types of epoxy resins having different softening points from urethane-modified polyester resins.

  The mixing mass ratio of the epoxy resin and the urethane-modified polyester resin is preferably in the range of 9: 1 to 6: 4. When the ratio of the urethane-modified polyester resin is below this range, the plasticizer resistance and the adhesion between the release layer and the adhesive layer are not sufficient. On the other hand, if the ratio of the urethane-modified polyester resin exceeds this range, the protective layer becomes yellowish, and the color of the image changes.

  As two types of epoxy resins having different softening points, a combination having a softening point of less than 100 ° C and a softening point of 100 ° C or more is preferable. In the case of an epoxy resin alone having a softening point of less than 100 ° C., blocking of the protective layer tends to occur when the thermal transfer sheet with the protective layer is rolled and stored at a high temperature. On the other hand, in the case of an epoxy resin alone having a softening point of 100 ° C. or higher, the thermal sensitivity is lowered, so that transfer with low energy is not possible, and the protective layer is too strong, not only the thermal transfer portion but also the non-thermal transfer portion. The problem of burr that peels up to a point occurs.

  As a result of diligent research, the inventors have used the above two types of epoxy resins at an appropriate blending ratio to provide an appropriate thermal sensitivity capable of thermal transfer without abnormality as a protective layer, and in a winding form before use. It has been found that a thermal transfer medium having both excellent storage stability can be provided. Specifically, the blending ratio of the epoxy resin having a softening point of less than 100 ° C. and the epoxy resin of 100 ° C. or more is preferably in the range of 3 to 7 to 7 to 3. When the epoxy resin having a softening point lower than 100 ° C exceeds this range, the protective layer is likely to be blocked when stored in a roll and stored at a high temperature, and the epoxy resin having a softening point of 100 ° C or higher exceeds this range. The thermal sensitivity is lowered, so that transfer with low energy cannot be performed, and the strength of the protective layer is too strong, and the sharpness at the time of thermal transfer is deteriorated.

  Examples of the epoxy resin include bisphenol A type, bisphenol F type, novolac type, brominated type, and alicyclic type epoxy resin. Therefore, it is particularly excellent in thermal stability and alcohol resistance and is suitable as a material. In addition, yellowing of the resin itself over time can be prevented. It is also suitable as a material from the viewpoint that the dyeability to the resin is small and the thermal transfer layer that has been transferred to the heat-resistant slipping layer by rewinding during the manufacturing process is further transferred to the protective layer, so that the so-called reverse transfer hardly occurs.

  In order to impart light resistance, it is essential that the adhesive layer (8) contains an ultraviolet absorber. Specific examples include benzotriazole-based, benzophenone-based, triazine-based, salicylate-based compounds and known compounds that improve image light resistance in photographs and other image recording materials, but in terms of high heat resistance, Benzotriazole ultraviolet absorbers are preferred.

  Examples of the benzotriazole ultraviolet absorber include 2- (2H-benzotriazol-2-yl) -p-cresol, 2- (2H-benzotriazol-2-yl) -46-bis (1-methyl-1-phenyl) Ethyl) phenol, 2- [5-chloro (2H) -benzotriazol-2-yl] -4-methyl-6- (tert-butyl) phenol, 2- (2H-benzotriazol-yl) -4,6- Di-tert-pentylphenol, 2- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol, and mixtures, modified products, polymers, and derivatives thereof. These can be exemplified, and these can be used alone or in combination.

  The amount of the ultraviolet absorber is preferably about 5 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the resin, although it depends on the ultraviolet absorbing ability of the ultraviolet absorber and the compatibility with the resin. When the addition amount is less than 5 parts by mass, there is a case where sufficient ultraviolet absorbing ability cannot be exhibited in the heat transferable protective layer. Moreover, when it exceeds 100 mass parts, it will influence the cohesion force in a layer, the toughness of a resin layer may fall, bleed will increase, transparency may be lacking, or it may block. Preferably, it is about 10 to 80 parts by mass.

The coating amount after drying of the adhesive layer (8) is not generally limited, but is preferably in the range of 0.5 to 1.0 g / m ² . When the thickness is less than 0.5 g / m ² , unevenness on the surface of the image receiving layer caused by heat at the time of image formation is noticeable in the printed matter, and there is a fear that the appearance is impaired. On the other hand, if it is thicker than 1.0 g / m ² , high energy is required for printing, and printing may be possible only with a special printer.

  For the adhesive layer (8), a release agent represented by phosphate ester, a slipping agent represented by wax, a light stabilizer, an antioxidant, a fluorescent whitening agent, and an antistatic agent, as long as the performance is not impaired. An agent or the like can be added.

  Moreover, in order to adjust the peeling weight of a protective layer (9) and a base material (1) in an appropriate range, and to ensure the stable peelability from a base material (1), a base material (1) A release layer may be formed between the protective layer 9 and the protective layer 9.

  The binder used in the release layer is not particularly limited. For example, water-soluble polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, sodium alginate, chlorinated rubber, cyclized rubber, etc. Natural rubber derivatives, waxes such as natural wax and synthetic wax, fiber derivatives such as nitrocellulose, cellulose and cellulose acetate propionate, acrylic, polyurethane, polyamide, polyimide, polyacetal, chlorinated polyolefin And thermoplastic resins such as vinyl chloride-vinyl acetate copolymer systems, melamine-based, epoxy-based, polyurethane-based, silicone-based thermosetting resins, and the like.

  Further, in order to improve the water repellency of the outermost layer after thermal transfer, the release layer may contain fine particles or the like to form irregularities.

  The heat resistant slipping layer (2), the thermal transfer layer (6), and the protective layer (9) can be formed by applying and drying by a conventionally known coating method. Examples of the application method include a gravure coating method, a screen printing method, a spray coating method, and a reverse roll coating method.

Hereinafter, the present invention will be described in detail by way of examples. In addition, as a base material, a PET film having a thickness of 4.5 μm that has been subjected to easy adhesion treatment on one side, and the following composition for forming a heat-resistant slipping layer on the other side is dried by a gravure coating method. The coating was applied so that the subsequent coating amount was 0.5 g / m ² , dried at 100 ° C. for 1 minute, and then aged in a 40 ° C. environment for 1 week to form a heat resistant slipping layer. In the text, “part” is based on mass unless otherwise specified.

<Composition for forming heat resistant slipping layer>
Acrylic polyol resin 21.0 parts Zinc stearate 0.40 parts Phosphate ester surfactant 3.70 parts Alumina (average particle size = 0.6 μm) 0.10 parts Tolylene diisocyanate 14.0 parts Toluene 42.6 Methyl ethyl ketone 18.2 parts

Example 1
A yellow transfer ink for forming a heat transfer layer, a magenta ink for forming a heat transfer layer, and a cyan ink for forming a heat transfer layer having the following composition are applied onto the surface of the above-mentioned easy adhesion treatment by a gravure coating method so that the coating amount after drying is 0.7 g / The thermal transfer layer was formed by applying the film in the order of m ² and drying at 80 ° C. for 1 minute. Further, the peeling layer coating solution-1 having the following composition was applied in a surface order so that the coating amount after drying was 0.6 g / m ² by a gravure coating method, and dried at 100 ° C. for 1 minute to peel off. A layer was formed. Subsequently, the adhesive layer coating liquid-1 having the following composition is applied onto the release layer by a gravure coating method so that the coating amount after drying is 1.1 g / m ² and dried at 100 ° C. for 1 minute. Thus, an adhesive layer was formed, and a thermal transfer sheet with a protective layer of the present invention was produced.

<Yellow ink for thermal transfer layer formation>
C. I. Solvent Yellow 93 7.5 parts C.I. I. Solvent Yellow 16 2.5 parts Polyvinyl acetal resin 10.0 parts Silicone modified resin 0.2 parts Methyl ethyl ketone 53.2 parts Toluene 26.6 parts

<Magenta ink for thermal transfer layer formation>
C. I. Disperse thread 60 5.0 parts C.I. I. Disperse Violet 26 5.0 parts Polyvinyl acetal resin 10.0 parts Silicone-modified resin 0.2 parts Methyl ethyl ketone 53.2 parts Toluene 26.6 parts

<Cyan ink for thermal transfer layer formation>
C. I. Solvent Blue 63 5.0 parts C.I. I. Solvent Blue 36 5.0 parts Polyvinyl acetal resin 10.0 parts Silicone-modified resin 0.2 parts Methyl ethyl ketone 53.2 parts Toluene 26.6 parts

<Peeling layer coating solution-1>
Acrylic resin (Mitsubishi Rayon Co., Ltd., BR85) 20.0 parts Toluene 40.0 parts Methyl ethyl ketone 40.0 parts

<Adhesive layer coating solution-1>
Epoxy resin A (softening point 97 ° C.) 18.24 parts Epoxy resin B (softening point 128 ° C.) 4.56 parts Urethane modified polyester resin 1.2 parts Benzophenone UV absorber 1.0 part Methyl ethyl ketone 75.0 parts

(Example 2)
A thermal transfer sheet with a protective layer was obtained in the same manner as in Example 1 except that the adhesive layer was changed to the adhesive layer coating solution-2 having the following composition.
<Adhesive layer coating solution-2>
Epoxy resin A (softening point 97 ° C.) 4.56 parts Epoxy resin B (softening point 128 ° C.) 18.24 parts Urethane-modified polyester resin 1.2 parts Benzophenone UV absorber 1.0 part Methyl ethyl ketone 75.0 parts

(Example 3)
A thermal transfer sheet with a protective layer was obtained in the same manner as in Example 1 except that the adhesive layer was changed to the adhesive layer coating solution-3 having the following composition.
<Adhesive layer coating solution-3>
Epoxy resin A (softening point 97 ° C.) 15.36 parts Epoxy resin B (softening point 128 ° C.) 3.84 parts Urethane modified poiester resin 4.8 parts Benzophenone UV absorber 1.0 part Methyl ethyl ketone 75.0 parts

Example 4
A thermal transfer sheet with a protective layer was obtained in the same manner as in Example 1 except that the adhesive layer was changed to the adhesive layer coating solution-4 having the following composition.
<Adhesive layer coating solution-4>
Epoxy resin A (softening point 97 ° C.) 3.84 parts Epoxy resin B (softening point 128 ° C.) 15.36 parts Urethane modified polyester resin 4.8 parts Benzophenone UV absorber 1.0 part Methyl ethyl ketone 75.0 parts

(Example 5)
A thermal transfer sheet with a protective layer was obtained in the same manner as in Example 1 except that the adhesive layer was changed to the adhesive layer coating solution-5 having the following composition.
<Adhesive layer coating solution-5>
Epoxy resin A (softening point 97 ° C.) 13.44 parts Epoxy resin B (softening point 128 ° C.) 5.76 parts Urethane modified polyester resin 4.8 parts Benzophenone UV absorber 1.0 part Methyl ethyl ketone 75.0 parts

(Example 6)
A thermal transfer sheet with a protective layer was obtained in the same manner as in Example 1 except that the adhesive layer was changed to the adhesive layer coating solution-6 having the following composition.
<Adhesive layer coating solution-6>
Epoxy resin A (softening point 97 ° C.) 13.44 parts Epoxy resin B (softening point 128 ° C.) 5.76 parts Urethane modified polyester resin 4.8 parts Benzotriazole UV absorber 1.0 part Methyl ethyl ketone 75.0 parts

(Example 7)
A thermal transfer sheet with a protective layer was obtained in the same manner as in Example 1 except that the adhesive layer was changed to the adhesive layer coating solution-7 having the following composition.
<Adhesive layer coating solution-7>
Epoxy resin A (softening point 97 ° C.) 10.08 parts Epoxy resin B (softening point 128 ° C.) 4.32 parts Urethane modified polyester resin 3.6 parts Benzotriazole ultraviolet absorber 7.0 parts Methyl ethyl ketone 75.0 parts

(Example 8)
A thermal transfer sheet with a protective layer was obtained in the same manner as in Example 7 except that the adhesive layer was coated and dried so that the coating amount after drying was 0.9 g / m ² .

Example 9
A thermal transfer sheet with a protective layer was obtained in the same manner as in Example 8 except that the release layer was changed to release layer coating solution-2 having the following composition.
<Peeling layer coating solution-2>
Acrylic resin 19.9 parts Polyester resin 0.1 part Toluene 40.0 parts Methyl ethyl ketone 40.0 parts

(Comparative Example 1)
A thermal transfer sheet with a protective layer was obtained in the same manner as in Example 9 except that the adhesive layer was changed to the adhesive layer coating solution-8 having the following composition.
<Adhesive layer coating solution-8>
Epoxy resin A (softening point 97 ° C.) 12.60 parts Epoxy resin B (softening point 128 ° C.) 5.4 parts Benzotriazole-based UV absorber 7.0 parts Methyl ethyl ketone 75.0 parts

(Comparative Example 2)
A thermal transfer sheet with a protective layer was obtained in the same manner as in Example 8 except that the adhesive layer was changed to the adhesive layer coating solution-9 having the following composition.
<Adhesive layer coating solution-9>
Urethane-modified acrylic polyol resin 18.0 parts Benzotriazole UV absorber 7.0 parts Methyl ethyl ketone 75.0 parts

(Comparative Example 3)
A thermal transfer sheet with a protective layer was obtained in the same manner as in Example 9 except that the adhesive layer was changed to the adhesive layer coating solution-10 having the following composition.
<Adhesive layer coating solution-10>
Epoxy resin B (softening point 128 ° C.) 14.4 parts Urethane-modified polyester resin 3.6 parts Benzotriazole-based UV absorber 7.0 parts Methyl ethyl ketone 75.0 parts

(Comparative Example 4)
A thermal transfer sheet with a protective layer was obtained in the same manner as in Example 9 except that the adhesive layer was changed to the adhesive layer coating solution-11 having the following composition.
<Adhesive layer coating solution-11>
Epoxy resin A (softening point 97 ° C.) 14.4 parts Urethane modified polyester resin 3.6 parts Benzotriazole ultraviolet absorber 7.0 parts Methyl ethyl ketone 75.0 parts

(Comparative Example 5)
A thermal transfer sheet with a protective layer was obtained in the same manner as in Example 9 except that the adhesive layer was changed to the adhesive layer coating solution-12 having the following composition.
<Adhesive layer coating solution-12>
Epoxy resin A (softening point 97 ° C.) 14.0 parts Epoxy resin B (softening point 128 ° C.) 6.0 parts Urethane modified polyester resin 5.0 parts Methyl ethyl ketone 75.0 parts

<Preparation of transfer object>
As a base material, a foamed polyester film of 188 μm is used, and on one surface, a thermal transfer image-receiving layer coating solution having the following composition is applied by a gravure coating method so that the coating amount after drying is 5.0 g / m ^2. After coating and drying, a transfer object for thermal transfer was produced by aging in a 40 ° C. environment for one week.
<Image-receiving layer coating solution for thermal transfer>
Vinyl chloride-vinyl acetate-vinyl alcohol copolymer 19.5 parts Amino-modified silicone oil 0.5 part Toluene 40.0 parts Methyl ethyl ketone 40.0 parts

<Evaluation and method>
About the thermal transfer sheet with a protective layer of Examples 1-9 and Comparative Examples 1-5, plasticizer resistance, light resistance, abnormal transfer of the protective layer, burr, blocking, and hue of the protective layer were evaluated by the following methods. The results are shown in Table 1 below.

(Plasticizer resistance)
Regarding the thermal transfer sheets with protective layers of Examples 1 to 9 and Comparative Examples 1 to 5, using thermal transfer sheets with protective layers stored at room temperature, yellow (Y), magenta (M), and cyan were used in a thermal simulator. (C), the protective layer is sequentially solid-printed on the transferred material under the following printing conditions,
A black solid print having a reflection density of 1.0 was obtained.
<Printing conditions> Printing environment: 23 ° C., 50% RH, applied voltage: 15 V, line cycle: 0.
7 msec, print density: 300 dpi sub-scan 300 dpi sub-scan

Next, the black solid print is cut out to 30 mm × 60 mm, and contacted with a dragonfly pencil MONO eraser (width 16.5 × total length 43 × thickness 11 mm), so that the weight is 200 g / cm ^2. After leaving for 48 hours in a 50 ° C. dry environment, the surface of the eraser and the surface of the printed material in contact with the printed material were observed. The evaluation was performed according to the following criteria. ◎ and ○ are practically no problem levels.
◎: Dye is not transferred to the eraser at all ○: Dye is transferred lightly to the eraser, but the printed image is not faded ×: Dye is transferred to the eraser, and the printed image is also faded

(Light resistance)
A black solid print having a reflection density of 1.0 produced by the above method was placed in a light resistance tester for evaluation of acceleration, and the retention was calculated from the difference in reflection density before and after the evaluation. The conditions of the light resistance test are as follows.
Illuminance: 100klux
Xenon lamp filter: (inside) borosilicate (outside) soda lime black Panel temperature: 40 ° C
Temperature and humidity in test chamber: 20 ° C 50%
Test time: 216 hours retention (%) = ((reflection density before test−reflection density after test) / density before test) × 100

(Abnormal transfer of protective layer)
The transfer state of the protective layer was confirmed using a black solid print having a reflection density of 1.0 produced by the above method. The evaluation was performed according to the following criteria.
○: The protective layer (peeling layer / adhesive layer) is transferred to the printed matter without any problem. X: Abnormal transfer occurs such as peeling between the peeling layer / adhesive layer.

(Bari)
The length of burrs at the end of the transfer region, which was generated when a black solid print having a reflection density of 1.0 was produced by the above method, was measured.

(blocking)
About the thermal transfer sheet with a protective layer of Examples 1-9 and Comparative Examples 1-5, it was left to stand for 96 hours or more in 40 degreeC90% RH atmosphere, and generation | occurrence | production of blocking was confirmed between the protective layer surface and the heat resistant slipping layer surface. . The evaluation was performed according to the following criteria. ◎ and ○ are practically no problem levels.
◎: No blocking occurred. ○: Slight blocking occurred at the winding core. ×: Blocking occurred.

(Hue of protective layer)
For the thermal transfer sheets with protective layers of Examples 1 to 9 and Comparative Examples 1 to 5, using a thermal transfer sheet with a protective layer stored at room temperature, using a thermal simulator, only the protective layer is printed on the transfer target, The hue of the print was measured using X-Rite 528.

<Comparison result>
From the results shown in Table 1, the thermal transfer sheets with protective layers of Examples 1 to 9 have good plasticizer resistance and light resistance, and burrs, blocking, adhesion between the release layer / adhesion layer, and the color of the protective layer are as follows. It was a level with no problem in practical use. On the other hand, the thermal transfer sheet with a protective layer of Comparative Example 1 in which the urethane-modified polyester resin is not contained in the binder resin has a weak protective layer strength, and there are some poor adhesion between the release layer and the adhesive layer. The plasticizer property was poor. In the thermal transfer sheet with a protective layer of Comparative Example 2 in which the binder resin was only urethane-modified polyester resin, the film strength was too strong, and thus burrs were generated, and the hue of the protective layer itself was large in b ^{* and} strong in yellow. In the thermal transfer sheet with a protective layer of Comparative Example 3 in which the binder resin was a urethane-modified polyester resin and an epoxy resin having a softening temperature of 100 ° C. or higher, burrs were generated because the film strength was too strong. The thermal transfer sheet with a protective layer of Comparative Example 4 in which the binder resin is a urethane-modified polyester resin and an epoxy resin having a softening temperature of less than 100 ° C. has a weak protective layer film strength and some poor adhesion between the release layer and the adhesive layer. Because there are places, the plasticizer resistance was poor. Moreover, blocking also occurred. The thermal transfer sheet with a protective layer of Comparative Example 5 to which no ultraviolet absorber was added had poor light resistance.

  The thermal transfer sheet with a protective layer obtained by the present invention can be used in a sublimation transfer type printer, and in addition to the high speed and high functionality of the printer, various images can be easily formed in full color. Can be widely used for cards such as ID cards, amusement output, etc.

1: Base material 2: Heat-resistant slip layer 3: Yellow layer 4: Magenta layer 5: Cyan layer 6: Thermal transfer layer 7: Release layer 8: Adhesive layer 9: Protective layer

Claims (6)

Thermal transfer with a protective layer in which a heat-resistant slipping layer is provided on one side of a substrate, and a thermal transferable ink layer of three colors, yellow, magenta, and cyan, and a thermal transferable protective layer are provided in the longitudinal direction on the other side. A sheet,
The thermal transferable protective layer is formed by sequentially laminating a release layer and an adhesive layer on the other surface of the base material,
The adhesive layer comprises two types of epoxy resins having a softening point of less than 100 ° C. and 100 ° C. or more, a urethane-modified polyester resin, and an ultraviolet absorber.
In addition, a thermal transfer sheet with a protective layer, wherein the blending ratio of the two types of epoxy resins is in the range of 3 to 7 to 7 to 3.   2. The thermal transfer sheet with a protective layer according to claim 1, wherein the blending ratio of the epoxy resin and the urethane-modified polyester resin in the adhesive layer is in the range of 9: 1 to 6: 4.   The thermal transfer sheet with a protective layer according to claim 1 or 2, wherein the ultraviolet absorber is a benzotriazole type.   The thermal transfer with a protective layer according to any one of claims 1 to 3, wherein the blending amount of the ultraviolet absorber in the adhesive layer is 5 to 100 parts by mass with respect to 100 parts by mass of the total resin. Sheet. The coating amount after drying of the adhesive layer, a protective layer with a thermal transfer sheet according to any one of claims 1 to 4, characterized in that it is 0.5 to 1.0 g / m ^2.   The said peeling layer consists of an acrylic resin and a polyester resin at least, The mass ratio of the said polyester resin is 0.3-2.0 of the whole resin, The one in any one of Claims 1-5 characterized by the above-mentioned. Thermal transfer sheet with protective layer.