Thermal transfer recording medium and printing apparatus

Abstract

Provided is a thermal transfer recording medium capable of recording characters of at least two colors having good clarity. A thermal transfer recording medium (47) includes: a base layer (48) having a front surface (53) and a back surface (54); and a fusion layer (70), a first thermal transfer layer (50), an intermediate layer (51), and a second thermal transfer layer (52) which are sequentially laminated on the front surface (53) of the base layer (48) so as to be in direct contact with each other. The fusion layer (70) has a solubility parameter (SP value) higher than the solubility parameter (SP value) of each of the base layer (48) and the first thermal transfer layer (50).

Description

Technical Field

[0001] The present invention relates to a thermal transfer recording medium capable of recording characters in different colors and a printing device for transferring the thermal transfer recording medium to a printed medium. Background Art

[0002] For example, Patent Documents 1 and 2 disclose thermal transfer recording media capable of recording text in different colors (for example, two colors, black and red). Such thermal transfer recording media are provided in a dedicated printing device. By adjusting the energy applied to the thermal head of the printing device, text in different colors can be transferred to the printed medium.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2000-094843

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 62-227788

[0007] Patent Document 3: Japanese Patent Application Laid-Open No. 63-214481 Summary of the invention

[0008] Technical problem to be solved by the invention

[0009] One embodiment of the present invention provides a thermal transfer recording medium capable of recording characters in at least two colors with good clarity.

[0010] Technical means for solving technical problems

[0011] A thermal transfer recording medium according to one embodiment of the present invention includes: a substrate layer having a first surface and a second surface; and a welding layer, a first thermal transfer layer, and a second thermal transfer layer, wherein the welding layer, the first thermal transfer layer, and the second thermal transfer layer are stacked in sequence on the first surface of the substrate layer in direct contact with each other, and the welding layer has a solubility parameter (SP value) higher than the solubility parameters (SP values) of the substrate layer and the first thermal transfer layer.

[0012] Effects of the Invention

[0013] A thermal transfer recording medium according to an embodiment of the present invention includes a fusion layer having a solubility parameter (SP value) higher than each solubility parameter (SP value) of a base layer and a first thermal transfer layer, and can therefore record text in at least two colors with good clarity. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1This is a diagram schematically showing the configuration of a printing device according to an embodiment of the present invention.

[0015] Figure 2 This is a block diagram showing the electrical structure of the printing device.

[0016] Figure 3 It is a schematic diagram explaining the heating process and the cooling process of the printing apparatus.

[0017] Figure 4A and Figure 4B It is a schematic diagram explaining the cooling process and the transfer process of the printing device.

[0018] Figure 5A and Figure 5B This is a diagram showing an example of a printing pattern by the printing device.

[0019] Figure 6 This is a schematic cross-sectional view showing a layer structure of an ink ribbon according to an embodiment of the present invention.

[0020] Figure 7 This is a diagram showing the relationship between the elapsed time in the heating step and the cooling step and the reaching temperature of the thermal transfer recording medium.

[0021] Figure 8 This is a diagram showing the relationship between the elapsed time in the heating step and the cooling step and the interlayer adhesive force of the thermal transfer recording medium.

[0022] Fig. 9 This is a diagram showing the relationship between the elapsed time in the heating step and the cooling step and the interlayer adhesive force of the thermal transfer recording medium.

[0023] Fig.10 It is a diagram showing a state in which the thermal transfer recording medium is peeled off.

[0024] Fig.11 It is a diagram showing a state in which the thermal transfer recording medium is peeled off.

[0025] Fig.12 It is a diagram showing a state in which the thermal transfer recording medium is peeled off.

[0026] Fig.13 It is a diagram showing a state in which the thermal transfer recording medium is peeled off.

[0027] Fig.14 It is a diagram showing a state in which the thermal transfer recording medium is peeled off.

[0028] Fig.15 It is a diagram showing a state in which the thermal transfer recording medium is peeled off.

[0029] Fig.16 It is a diagram showing a state in which the thermal transfer recording medium is peeled off.

[0030] Fig.17 It is a diagram showing a state in which the thermal transfer recording medium is peeled off.

[0031] Fig.18 This is a diagram for comparing the solubility parameters (SP values) of the constituent materials of the thermal transfer recording medium according to one embodiment of the present invention.

[0032] Fig.19 This is a diagram showing the relationship between the type of material constituting a part of the thermal transfer recording medium and the magnitude of the solubility parameter. DETAILED DESCRIPTION

[0033] Next, embodiments of the present invention will be described in detail with reference to the drawings.

[0034] [Overall Structure of Printing Device 1]

[0035] Figure 1 It is a diagram schematically showing the structure of a printing device 1 according to an embodiment of the present invention.

[0036] Reference Figure 1 The printing device 1 is a thermal transfer printer that transfers ink from an ink ribbon 3 as text to a printing tape 2 as an example of a printed medium. The printing tape 2 may include, for example, a strip-shaped film tape including a substrate to which the ink is directly transferred, a paper label tape having a plurality of paper labels arranged on a strip-shaped substrate, or the like.

[0037] The characters recorded on the printing tape 2 may include, for example, typical characters, symbols such as barcodes and QR codes (registered trademarks), numbers, figures, patterns, etc. The printing device 1 according to this embodiment can record characters in different colors (for example, two colors, black and red) on the printing tape 2 .

[0038] The printing device 1 mainly includes a housing 4 , a tape cassette 5 accommodated in the housing 4 , a thermal head 6 , a platen cylinder 7 , and a control substrate 8 .

[0039] The housing 4 may be, for example, a box-shaped member made of a plastic shell. An outlet 9 for taking out the printed printing tape 2 is formed on the outer wall of the housing 4. A cutter (not shown) may be provided near the outlet 9. The printing tape 2 can be separated into labels of a size per unit of use by cutting with the cutter and taken out.

[0040] The tape cassette 5 may be a detachable cassette relative to the housing 4. The tape cassette 5 may be moved in the tape conveying direction D1 (in Figure 1The printing tape roll 10 (in other words, it may be a label tape roll), the supply roller 11, the ink ribbon roll 12, the ink ribbon peeling member 13, and the ink ribbon winding roll 14 are sequentially accommodated from the upstream side to the downstream side (in a direction from the right side to the left side). In this embodiment, the printing tape roll 10 and the ink ribbon roll 12 are of the type used in a state of being accommodated in the tape cassette 5, but, for example, they may also be of the type used by being directly mounted on the printing device 1.

[0041] The printing tape roll 1 is made by winding the printing tape 2 into a cylindrical shape, and is rotatably held in the tape cassette 5, for example. A tape drive shaft 16 provided in the housing 4 is inserted into the supply roller 11. The rotational force R1 generated by the drive of the tape drive shaft 16 is transmitted to the supply roller 11, so that the supply roller 11 rotates.

[0042] The ink ribbon roller 12 is made by winding the ink ribbon 3 into a cylindrical shape, and is rotatably held in the ribbon cassette 5, for example. The ink ribbon drive shaft 18 provided in the housing 4 is inserted into the ink ribbon winding roller 14. The rotational force R2 generated by the driving of the ink ribbon drive shaft 18 is transmitted to the ink ribbon winding roller 14, so that the ink ribbon winding roller 14 rotates.

[0043] The ink ribbon peeling member 13 may be a guide member for changing the conveying direction D2 of the ink ribbon 3. The ink ribbon peeling member 13 may have a shape capable of abutting against the ink ribbon 3 being conveyed, such as a roller shape or a blade shape. The ink ribbon 3 is partially thermally pressed against the printing ribbon 2 by the thermal head 6, and is conveyed toward the removal port 9 together with the printing ribbon 2. The ink ribbon peeling member 13 abuts against the ink ribbon 3 being conveyed, and changes the conveying direction D2 of the ink ribbon 3 at a large angle relative to the conveying direction D1 of the printing ribbon 2. As a result, the printing ribbon 2 and the ink ribbon 3 are pulled apart, and the ink ribbon 3 is peeled off from the printing ribbon 2.

[0044] The thermal head 6 is disposed between the printing tape roller 10, the ink ribbon roller 12, and the ink ribbon peeling member 13 in the conveying direction D1 of the printing tape 2. The thermal head 6 includes a substrate 19 and a heating element 20 (for example, a heating resistor, etc.) formed on the substrate 19. The Joule heat generated by the energization of the heating element 20 is used for thermal transfer of the ink of the ink ribbon 3.

[0045] The platen drive shaft 21 provided in the housing 4 is inserted into the platen cylinder 7. The rotational force R3 generated by driving the platen drive shaft 21 is transmitted to the platen cylinder 7, so that the platen cylinder 7 rotates. The control board 8 is an electronic device that performs electrical control of the printing device 1, and is provided inside the housing 4.

[0046] [Electrical Structure of Printing Device 1]

[0047] Figure 2 It is a block diagram showing the electrical structure of the printing device 1 .

[0048] Reference Figure 2 The control circuit 22 is provided on the control substrate 8 of the printing device 1. The control circuit 22 may include a CPU 23, a ROM 24, a memory 25, a RAM 26, and an input / output I / F 27 (interface). These are electrically connected via a data bus (not shown), for example.

[0049] The ROM 24 stores various programs for driving the printing device 1 (for example, executing Figure 3 and Figure 4A , B, etc.). The CPU 23 uses the temporary storage function of the RAM 26 and performs signal processing according to the program stored in the ROM 24, thereby controlling the printing device 1 as a whole. The memory 25 can be composed of, for example, a part of the storage area of ​​the ROM 24. The memory 25 can store in advance a table for displaying the remaining amount (consumption) of the ink ribbon 3 on the display unit (not shown) of the housing 4.

[0050] The first drive circuit 28 and the second drive circuit 29 are electrically connected to the input / output I / F 27. The first drive circuit 28 performs energization control of the heating element 20 of the thermal head 6.

[0051] The second drive circuit 29 performs drive control to output drive pulses to the drive motor 30 which drives the supply roller 11 , the ribbon winding roller 14 , and the impression roller 7 to rotate.

[0052] [Flow of Printing Process by Printing Device 1]

[0053] Figure 3 It is a schematic diagram for explaining the heating process and the cooling process of the printing apparatus 1 . Figure 4A and Figure 4B It is a schematic diagram for explaining the cooling process and the transfer process of the printing device 1 . Figure 4B is from Figure 4A This is an enlarged view of the main part when the transfer pattern is viewed in the direction of arrow 4B. Figure 5A and Figure 5B 1 is a diagram showing an example of a printed pattern 44 by the printing device 1. Figure 1 and Figure 3 to Figure 5A and Figure 5B , the printing process based on the printing device 1 is specifically described.

[0054] When printing characters on the printing tape 2 , the printing tape 2 is fed out from the printing tape roll 10 by the rotational drive of the supply drum 11 , and the ink ribbon 3 is fed out from the ink ribbon roll 12 by the rotational drive of the ink ribbon take-up roller 14 .

[0055] Therefore, if Figure 1 and Figure 3As shown, the printing tape 2 and the ink ribbon 3 are conveyed toward the downstream side in a state where they overlap each other. In the printing tape 2, the surface on the ink ribbon 3 side is a printing surface 31 (front surface), and the surface on the opposite side is a back surface 32. In the ink ribbon 3, the surface on the printing tape 2 side is an adhesive surface 33 (front surface), and the surface on the opposite side is a back surface 34.

[0056] Reference Figure 3 The ink ribbon 3 includes: a base layer 35, a first ink layer 36 as an example of a first thermal transfer layer, and a second ink layer 37 as an example of a second thermal transfer layer. The first ink layer 36 and the second ink layer 37 are sequentially stacked on a surface 38 as an example of a first surface of the base layer 35. The surface on the opposite side of the surface 38 of the base layer 35 is a back surface 39 (back surface 34 of the ink ribbon 3). The first ink layer 36 and the second ink layer 37 contain colorants of different colors from each other. For example, the first ink layer 36 may contain a black colorant as an example of a first ink, and the second ink layer 37 may contain a red colorant as an example of a second ink.

[0057] The ink ribbon 3 is conveyed toward the thermal head 6 in a state where the second ink layer 37 is in contact with the printing ribbon 2. In the thermal head 6, as shown in FIG. Figure 3 Specifically, the heating element 20 that generates heat by energizing is pressed against the ink ribbon 3, so that the heat is transferred to the first ink layer 36 and the second ink layer 37 via the base layer 35. The stack of the ink ribbon 3 and the printing ribbon 2 is sandwiched between the thermal head 6 and the platen roller 7, so that it is transported to the downstream side while being heated by the thermal head 6.

[0058] The heating element 20 can be controlled to have the same temperature as a whole, or to have different temperatures in parts. Figure 3 As shown, the first portion 40 of the heating element 20 may be controlled to be a first heating temperature, and the second portion 41 of the heating element 20 may be controlled to be a second heating temperature different from the first heating temperature. Thus, the ink ribbon 3 may include a first portion 42 heated by the first heating temperature and a second portion 43 heated by the second heating temperature. In the first portion 42 and the second portion 43 of the ink ribbon 3, at least a portion or all of the first ink layer 36 and the second ink layer 37 are melted or softened, thereby being in close contact with the printing ribbon 2.

[0059] Reference Figure 3 and Figure 4A , B, a cooling process is performed in the area between the thermal head 6 and the ink ribbon stripping member 13. Specifically, the ink ribbon 3 that has been thermally pressed to the printing ribbon 2 in the heating process is naturally cooled in the area from the thermal head 6 to the ink ribbon stripping member 13, and the temperature is reduced toward the use environment temperature of the printing device 1.

[0060] Afterwards, if Figure 4AAs shown in FIG. 2 and FIG. 3 , the ink ribbon peeling member 13 selectively changes only the conveying direction D2 of the ink ribbon 3, thereby applying an external force F1 to the base material layer 35 and the second ink layer 37 in a direction away from each other. As a result, the printing ribbon 2 and the ink ribbon 3 are pulled apart, and the ink ribbon 3 is wound around the ink ribbon winding roller 14. At this time, in the ink ribbon 3, the first portion 42 and the second portion 43 heated by the thermal head 6 are selectively left on the printing ribbon 2, thereby performing the transfer process. For example, in the first portion 42, the base material layer 35 and the laminated body including the first ink layer 36 and the second ink layer 37 can be peeled off and the laminated body can be transferred. On the other hand, in the second portion 43, the first ink layer 36 and the second ink layer 37 can be peeled off and the second ink layer 37 can be selectively transferred.

[0061] Thus, a printed pattern 44 of different colors (for example, two colors, black and red) is formed on the printing tape 2. Figure 5A As shown, the printed pattern 44 can have different colors for each individual character. Figure 5A In the example, when viewed from the printing surface 31 of the printing tape 2, the red pattern 45 based on the second ink layer 37 can be seen on the outermost surface of the letters "A" and "C", and the black pattern 46 based on the first ink layer 36 can be seen on the outermost surface of "B". Figure 5B As shown, the printed pattern 44 can also be seen in both a red pattern 45 and a black pattern 46 for each character portion.

[0062] After the transfer of the ink ribbon 3 , the printing tape 2 on which the characters are recorded is taken out from the take-out port 9 of the printing device 1 .

[0063] [An example of a problem in two-color printing]

[0064] In the thermal transfer type thermal printer (printing device 1), after the ink ribbon 3 is heated by the thermal head 6 according to the pattern of recording information, the ink ribbon 3 is peeled off from the printing tape 2. As a result, the ink layers 36 and 37 are selectively melted or softened according to the heating pattern, and are peeled off from the base material layer 35 and transferred to the printing surface 31 of the printing tape 2, and text is recorded on the printing surface 31. The above-mentioned patent documents 1 and 2 also disclose the above-mentioned two-color thermal transfer printing, which has the following problems.

[0065] For example, Patent Document 1 discloses a thermal transfer sheet comprising a substrate and a plurality of thermal transfer ink layers (e.g., a first thermal transfer ink layer and a second thermal transfer ink layer) of different hues stacked on the substrate for two-color recording. The two thermal transfer ink layers are respectively formed of thermoplastic resin, wax, etc.

[0066] In Patent Document 1, for example, when relatively low energy is applied to the thermal head and thermal transfer is performed at a relatively low temperature, the first thermal transfer ink layer softens and its adhesion to the substrate decreases, and the second thermal transfer ink layer softens and generates adhesion to the surface of the transfer object.

[0067] However, as a result of the two thermal transfer ink layers softening together and maintaining the adhesion, the entire thermal transfer ink layer, that is, the first thermal transfer ink layer and the second thermal transfer ink layer, are thermally transferred to the surface of the transfer object as a whole. Therefore, the text recorded on the surface of the transfer object, for example, becomes the color tone of the first thermal transfer ink layer located on the outermost layer after transfer, such as black.

[0068] On the other hand, when relatively high energy is applied to the thermal head and thermal transfer is performed at a higher temperature, the first thermal transfer ink layer softens further, and in turn the adhesion force relative to the substrate increases, and the second thermal transfer ink layer softens to generate adhesion force relative to the surface of the transfer body. During this thermal transfer, the so-called reverse transfer occurs in which the first thermal transfer ink layer remains on the substrate side. Therefore, only the second thermal transfer ink layer is selectively thermally transferred to the surface of the transfer body. Therefore, the text recorded on the surface of the transfer body becomes the color tone of the second thermal transfer ink layer, such as red.

[0069] However, between the range of transfer temperature (≈ the energy applied to the thermal head, the same below) when the two thermal transfer ink layers are thermally transferred as a whole (hereinafter, may be abbreviated as the "low-temperature transfer range") and the range of transfer temperature when only the second thermal transfer ink layer is thermally transferred (hereinafter, may be abbreviated as the "high-temperature transfer range"), there may be a range of transfer temperatures in which a portion of the first thermal transfer ink layer is transferred together with the second thermal transfer ink layer, thereby causing the tone of the text to become turbid (hereinafter, may be abbreviated as the "turbid transfer range").

[0070] Moreover, in the thermal transfer sheet with two thermal transfer ink layers directly laminated, there is a tendency that the turbid transfer range is large, the low temperature transfer range and the high temperature transfer range become small. In addition, there is a tendency that due to continuous thermal transfer printing, heat accumulates in the thermal head and the temperature of the thermal head gradually rises.

[0071] Therefore, it is particularly difficult to maintain the temperature of the thermal head in the low-temperature transfer range, and the color tone of characters is easily muddy during low-temperature transfer.

[0072] The thermal transfer sheet of patent document 1 may also include a peeling layer formed between the first thermal transfer ink layer and the second thermal transfer ink layer. The peeling layer is composed of colorless, transparent, low melting viscosity and high fluidity wax or the like. The peeling layer melts or softens during thermal transfer, thereby promoting the separation of the two thermal transfer ink layers. The high-temperature transfer range can be expanded to the lower temperature side, thereby reducing the turbid transfer range. However, the low-temperature transfer range that suppresses the peeling of the peeling layer and can transfer the two thermal transfer ink layers as a whole tends to shrink. In addition, the wax has a low melting viscosity, so it is easy to affect the surroundings. In particular, when recording fine images such as bar codes, unnecessary peeling will occur, which may reduce the clarity of the recording.

[0073] Patent document 2 discloses an ink ribbon including a substrate and a first ink layer and a second ink layer directly stacked on the substrate. In Patent document 2, it is studied that the ink ribbon is first heated in a low temperature transfer range to thermally transfer the two ink layers to the surface of the substrate as a whole. Afterwards, when only the second ink layer remains, the ink ribbon is heated again when peeling off, so that the first ink layer is reversely transferred to the substrate side. However, the thermal transfer printing of Patent document 2 requires a printer with a special thermal head that can be heated again after thermal transfer, and has a problem of low versatility.

[0074] The inventors of the present application have found multiple problems in view of the thermal transfer methods of Patent Documents 1 and 2. At least one of the multiple problems (first problem) is to provide a thermal transfer recording medium (ink ribbon) capable of simultaneously recording text in at least two colors with good clarity.

[0075] Another of the above-mentioned problems (second problem) is to provide a thermal transfer recording medium (ink ribbon) that can clearly separate two colors without turbidity of color even when thermal transfer recording is performed continuously using a general-purpose thermal transfer printer that supports two-color recording.

[0076] Another of the multiple topics (the third topic) is to provide a universal thermal transfer printer that uses two-color recording, which can make the color tone less likely to be turbid and clearly separate the two colors even if the thermal transfer recording is performed continuously, and will not produce excess peeling and can produce a thermal transfer recording medium (ink ribbon) that can record text with excellent clarity.

[0077] [Introduction of Welding Layer 70]

[0078] In order to solve the above-mentioned problems, the inventors of the present application studied and implemented the introduction of a fusion layer into a thermal transfer recording medium (ink ribbon), which will be described in detail below.

[0079] Figure 6 FIG. 4 is a schematic cross-sectional view showing a layer structure of a thermal transfer recording medium 47 according to an embodiment of the present invention. Figure 6, a thermal transfer recording medium 47 is shown in a state of being bonded to a printing tape 2 as an example of a medium to be printed.

[0080] The thermal transfer recording medium 47 can be used as the ink ribbon 3 for Figure 1 to Figure 4A , and the printing device 1 and the printing process shown in B. The thermal transfer recording medium 47 includes: a base layer 48, a back layer 49, a fusion layer 70, a first thermal transfer layer 50, an intermediate layer 51, and a second thermal transfer layer 52. The fusion layer 70, the first thermal transfer layer 50, the intermediate layer 51, and the second thermal transfer layer 52 are sequentially stacked on a surface 53, which is an example of a first surface of the base layer 48. The surface of the base layer 48 on the opposite side to the surface 53 may be a back surface 54. The back layer 49 is stacked on the back surface 54 of the base layer 48. The first thermal transfer layer 50 and the second thermal transfer layer 52 may be referred to as a first ink layer and a second ink layer, respectively.

[0081] The thermal transfer recording medium 47 of the present invention is characterized by comprising a base layer 48 and a fusion layer 70, a first thermal transfer layer 50, an intermediate layer 51, and a second thermal transfer layer 52 which are sequentially stacked in direct contact with each other on a surface 53 of the base layer 48. The intermediate layer 51 contains a thermoplastic elastomer as an adhesive. The intermediate layer 51 may also be omitted.

[0082] Hereinafter, specific components and physical properties of the base layer 48 , the back layer 49 , the fusion layer 70 , the first thermal transfer layer 50 , the intermediate layer 51 , and the second thermal transfer layer 52 included in the thermal transfer recording medium 47 will be described in detail.

[0083] (1) Base material layer 48

[0084] As the substrate layer 48, for example, films of resins such as polysulfone, polystyrene, polyamide, polyimide, polycarbonate, polypropylene, polyester, and cellulose triacetate, thin paper such as capacitor paper and glassine paper, and cellophane can be cited. Among these, films of polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate are preferred from the viewpoints of mechanical strength, dimensional stability, heat treatment resistance, price, etc. The thickness of the substrate layer 48 can be arbitrarily set according to the specifications of the thermal transfer printer, etc. For example, the thickness of the substrate layer 48 is 1 μm or more, preferably 2 μm or more.

[0085] For example, the thickness of the base material layer 48 is 10 μm or less, preferably 8 μm or less. For example, the thickness of the base material layer 48 is 1 μm or more and 10 μm or less, preferably 2 μm or more and 8 μm or less.

[0086] (2) Back layer 49

[0087] The back layer 49 improves the heat resistance, sliding property, and scratch resistance of the back surface 54 of the base material layer 48 in contact with the thermal head 6. Examples of the back layer 49 include silicone resin, fluororesin, silicone-fluorine copolymer resin, nitrocellulose resin, silicone-modified polyurethane resin, and silicone-modified acrylic resin. The back layer 49 may contain a lubricant as needed.

[0088] The back layer 49 can be formed, for example, by applying a coating obtained by dissolving or dispersing the above-mentioned resin or the like in an arbitrary solvent to the back surface 54 of the base material layer 48 and then drying the coating. The thickness of the back layer 49 can be arbitrarily set according to the specifications of a thermal transfer printer, for example. The thickness of the back layer 49 can be adjusted by the amount of the back layer 49 applied.

[0089] For example, the coating amount of the back surface layer 49 is 0.05 g / m 2 Above, preferably 0.1 g / m 2 For example, the coating amount of the back layer 49 is 0.5 g / m 2 Below, preferably 0.4g / m 2 For example, the coating amount of the back surface layer 49 is expressed as 0.05 g / m 2 Above and 0.5g / m 2 Below, preferably 0.1g / m 2 Above and 0.4g / m 2 The specific thickness of the back layer 49 is, for example, 0.05 μm or more, preferably 0.1 μm or more. The thickness of the back layer 49 is, for example, 0.5 μm or less, preferably 0.4 μm or less. The thickness of the back layer 49 can be, for example, 0.05 μm or more and 0.5 μm or less, preferably 0.1 μm or more and 0.4 μm or less.

[0090] (3) Welding layer 70

[0091] The welding layer 70 includes, for example, at least one selected from the group consisting of polyamide resin, polyester resin, epoxy resin, phenolic resin, and polyvinyl alcohol resin. In view of improving affinity and adhesion with respect to the base layer 48 and the first thermal transfer layer 50 during low-temperature heating, the welding layer 70 is preferably formed using a polyamide resin.

[0092] Examples of the polyamide resin include polyamides obtained by polycondensation of three-membered or higher-ring lactams, polymerizable aminocarboxylic acids, dibasic acids and diamines or salts thereof, or mixtures thereof. These polyamide resins can be used alone or in combination of two or more.

[0093] Specific commercial products of polyamide resins include, for example, 1310 (softening point: 120±5°C, melt viscosity: 1500 to 4500 mPa·s / 200°C), 1315 (softening point: 130±5°C, melt viscosity: 7000 to 18000 mPa·s / 200°C), 1320 (softening point: 100±5°C, melt viscosity: 11000 to 20000 mPa·s / 200°C) of the Tohmide (registered trademark) series manufactured by T&K TOKA Co., Ltd. ·s / 200℃), 1340 (softening point: 140±5℃, melt viscosity: 8000~16000mPa·s / 200℃), TXC-243A (softening point: 105±5℃, melt viscosity: 5000~10000mPa·s / 200℃), TXC-245A (softening point: 90±5℃, melt viscosity: 1000~2000mPa·s / 200℃), etc.

[0094] In addition, in the present application, when comparing the temperatures related to the thermal deformation of a plurality of substances, in the case of a substance having a softening point such as a polyamide resin, the softening point is used as the comparison temperature. In the case of a substance having a melting point (for example, wax described later), the melting point is used as the comparison temperature. In the case of a substance having a glass transition temperature without having both a melting point and a softening point (for example, a polyester resin described later), the glass transition temperature is used as the comparison temperature.

[0095] Specific commercially available products of polyester resins include, for example, UE-3320, UE-9820, UE-3350, UE-3380, etc. in the UNILATE (registered trademark) series produced by Unitika Co., Ltd., and 200 (glass transition temperature: 67°C), 600 (glass transition temperature: 47°C), GK-360 (glass transition temperature: 56°C), GK-810 (glass transition temperature: 46°C), GK-680 (glass transition temperature: 10°C), etc. in the VYLON (registered trademark) series produced by Toyobo Co., Ltd.

[0096] Specific commercial products of epoxy resins include, for example, 1001 (softening point (ring and ball method): 64°C, number average molecular weight Mn: about 900), 1002 (softening point (ring and ball method): 78°C, number average molecular weight Mn: about 1200), 1003 (softening point (ring and ball method): 89°C, number average molecular weight Mn: about 1300), 1055 (softening point (ring and ball method): 93°C, number average molecular weight Mn: about 1600), 1004 (softening point (ring and ball method): 97°C, number average molecular weight Mn: about 1650), 1004AF (softening point (ring and ball method): 98°C, number average molecular weight Mn: about 1600), and 1005 (softening point (ring and ball method): 106°C, number average molecular weight Mn: about 1800). ), 1005F, 1009F (softening point (Ring and Ball method): 144°C, number average molecular weight Mn: about 144°C), 1004FS (softening point (Ring and Ball method): 100°C), 1006FS (softening point (Ring and Ball method): 112°C), 1007FS (softening point (Ring and Ball method): 124°C).

[0097] Specific commercial products of phenolic resins include, for example, TD-2131 (softening point: 78 to 82° C.), TD-2106 (softening point: 88 to 95° C.), TD-2093 (softening point: 98 to 102° C.), TD-2090 (softening point: 117 to 123° C.) in the PHENOLITE (registered trademark) series manufactured by DIC Corporation, and BRG-555 (softening point: 66 to 72° C., melt viscosity: 0.3 to 0.5 Pa·s / 125° C.) in the SHOWNOL (registered trademark) series manufactured by AICA Industries, Ltd. ), BRG-556 (softening point: 77~83℃, melt viscosity: 0.1~0.3Pa·s / 150℃), BRG-557 (softening point: 82~88℃, melt viscosity: 0.2~0.4Pa·s / 150℃), BRG-558 (softening point: 93~98℃, melt viscosity: 0.8~1.2Pa·s / 150℃), CRG-951 (softening point: 93~99℃, melt viscosity: 0.2~0.8Pa·s / 150℃), TAM-005 (softening point: 80~88℃, melt viscosity: 0.3~0.5Pa·s / 150℃), etc.

[0098] As the polyvinyl alcohol-based resin, for example, a partially saponified polyvinyl alcohol-based resin having a saponification degree of 90 or less is preferred. In addition, the degree of polymerization of the polyvinyl alcohol-based resin is, for example, 2000 or less, preferably about 500. Specific commercially available products of the polyvinyl alcohol-based resin include, for example, B-05 (saponification degree: 86.5 to 89.5 mol %, polymerization degree: about 500, viscosity (4%, 20°C): 5.0 to 6.0 mPa·s), B-17 (saponification degree: 87.0 to 89.0 mol %, polymerization degree: about 1600, viscosity (4%, 20°C): 21 to 25 mPa·s), B-20 (saponification degree: 87.0 to 89.0 mol %, polymerization degree: about 2000, viscosity (4%, 20°C): 27 to 33 mPa·s) in the DENKA POVAL (registered trademark) series manufactured by DENKA (Co., Ltd.), and Kuraray Poval (registered trademark) series: 48-80 (saponification degree: 78.5 to 80.5 mol%, viscosity (4%, 20°C): 45.0 to 51.0 mPa·s), 3-88 (saponification degree: 87.0 to 89.0 mol%, viscosity (4%, 20°C): 3.2 to 3.6 mPa·s), 5-88 (saponification degree: 86.5 to 89.0 mol%, viscosity (4%, 20°C): 4.6 to 5.4 mPa·s), etc.

[0099] The softening point of the polyamide resin used for the welding layer 70 is, for example, 90° C. or higher, preferably 110° C. or higher, and more preferably 125° C. or higher. When the softening point is within this range, the high adhesive force between the base layer 48 and the first thermal transfer layer 50 can be maintained without softening at a relatively low temperature during low-temperature transfer.

[0100] The welding layer 70 can be formed, for example, by applying a coating obtained by dissolving or dispersing a material for forming the welding layer 70 in an arbitrary solvent onto the surface 53 of the base layer 48 and then drying the coating.

[0101] The thickness of the welding layer 70 can be arbitrarily set according to the specifications of the thermal transfer printer, for example. The thickness of the welding layer 70 can be adjusted by the coating amount of the welding layer 70. For example, the coating amount of the welding layer 70 is expressed as 0.1 g / m 2 Above, preferably 0.2 g / m 2 For example, the coating amount of the welding layer 70 is expressed as 1.5 g / m 2 Below, preferably 1.0g / m 2 For example, the coating amount of the welding layer 70 is expressed as 0.1 g / m 2 Above and 1.5g / m2 Below, preferably 0.2g / m 2 Above and 1.0g / m 2 the following.

[0102] The specific thickness (before printing) of the welding layer 70 may be, for example, 0.05 μm or more and 1.5 μm or less, preferably 0.2 μm or more and 1.0 μm or less. The thickness of the welding layer 70 can be confirmed based on, for example, a SEM (Scanning Electron Microscope) image or a TEM (Transmission Electron Microscope) image of the thermal transfer recording medium 47.

[0103] (4) First thermal transfer layer 50

[0104] The first thermal transfer layer 50 can be formed, for example, by any thermoplastic resin. In order to improve the affinity and adhesion to the welding layer 70 and the intermediate layer 51, the first thermal transfer layer 50 is preferably formed by using epoxy resin as the thermoplastic resin. Epoxy resin has excellent affinity and adhesion to the base layer 48 composed of a polyester film such as PET and the thermoplastic elastomer forming the intermediate layer 51. The first thermal transfer layer 50 can be formed by using epoxy resin as the thermoplastic resin in a state where the hardener is not added (removed).

[0105] As epoxy resin, for example, bisphenol A epoxy resin, bisphenol F epoxy resin, phenol novolac epoxy resin, resol novolac epoxy resin, alicyclic epoxy resin, hydrogenated bisphenol A epoxy resin, hydrogenated bisphenol AD ​​epoxy resin, propylene glycol ether, aliphatic epoxy resins such as pentaerythritol polyglycidyl ether, epoxy resins obtained from aliphatic or aromatic amines and epichlorohydrin, epoxy resins obtained from aliphatic or aromatic carboxylic acids and epichlorohydrin, heterocyclic epoxy resins, spiro-ring-containing epoxy resins, epoxy-modified resins, brominated epoxy resins, etc. can be listed. As specific examples of epoxy resin, there is no particular limitation, but for example, the following various epoxy resins can be listed. These epoxy resins can be used alone or in combination of two or more.

[0106] The basic solid types of JER (registered trademark) series epoxy resins manufactured by Mitsubishi Chemical Corporation include 1001 (softening point (ring and ball method): 64°C, number average molecular weight Mn: about 900), 1002 (softening point (ring and ball method): 78°C, number average molecular weight Mn: about 1200), 1003 (softening point (ring and ball method): 89°C, number average molecular weight Mn: about 1300), 1055 (softening point (ring and ball method): 93°C, number average molecular weight Mn: about 1600), 1004 (softening point (ring and ball method): 97°C, number average molecular weight Mn: about 1650), 1004AF (softening point (ring and ball method): 97°C, number average molecular weight Mn: about 1650), 1007 (softening point (ring and ball method): 128°C, number average molecular weight Mn: about 2900), 1009 (softening point (ring and ball method): 144°C, number average molecular weight Mn: about 3800), 1010 (number average molecular weight Mn: about 5500), 1003F (softening point (ring and ball method): 96°C), 1004F (softening point (ring and ball method): 103°C), 1005F, 1009F (softening point (ring and ball method): 144°C), 1004FS (softening point (ring and ball method): 100°C), 1006FS (softening point (ring and ball method): 112°C), 1007FS (softening point (ring and ball method): 124°C).

[0107] The softening point of the epoxy resin used for the first thermal transfer layer 50 is, for example, 95° C. or higher, preferably 110° C. or higher, and more preferably 125° C. or higher.

[0108] The first thermal transfer layer 50 may contain an adhesive in addition to the epoxy resin. By containing an adhesive, the affinity and adhesion to the welding layer 70 and the intermediate layer 51 can be further improved. Examples of the adhesive include rubber adhesives, acrylic adhesives, silicone adhesives, vinyl alkyl ether adhesives, polyvinyl alcohol adhesives, polyvinyl pyrrolidone adhesives, polyacrylamide adhesives, and cellulose adhesives.

[0109] In order to improve the affinity and compatibility with epoxy resin and the affinity and adhesion with the welding layer 70 and the intermediate layer 51, an acrylic adhesive is preferably used as the adhesive. There is no particular limitation on specific examples of the acrylic adhesive, but the following various acrylic adhesives can be cited. These acrylic adhesives can be used alone or in combination of two or more.

[0110] BPS1109 (non-volatile content: 39.5% by mass), BPS3156D (non-volatile content: 34% by mass), BPS4429-4 (non-volatile content: 45% by mass), BPS4849-40 (non-volatile content: 40% by mass), BPS5160 (non-volatile content: 33% by mass), BPS5213K (non-volatile content: 40% by mass), BPS5160 (non-volatile content: 33% by mass), BPS5213K (non-volatile content: 40% by mass), BPS5156D (non-volatile content: 34 ... BPS5215K (non-volatile content: 39 mass%), BPS5227-1 (non-volatile content: 41.5 mass%), BPS5296 (non-volatile content: 37 mass%), BPS5330 (non-volatile content: 40 mass%), BPS5375 (non-volatile content: 45 mass%), BPS5448 (non-volatile content: 40 mass%), BPS5513 (non-volatile content: 44.5 mass%), BPS 5565K (non-volatile content: 45 mass%), BPS5669K (non-volatile content: 46 mass%), BPS5762K (non-volatile content: 45.5 mass%), BPS5896 (non-volatile content: 37 mass%), BPS5978 (non-volatile content: 35 mass%), BPS6074HTF (non-volatile content: 52 mass%), BPS6080TFK (non-volatile content: 45 mass%), BPS6130TF (non-volatile content: 5 volatile component: 45.5 mass %), BPS6153K (non-volatile component: 25 mass %), BPS6163 (non-volatile component: 37 mass %), BPS6231 (non-volatile component: 56 mass %), BPS6421 (non-volatile component: 47 mass %), BPS6430 (non-volatile component: 33 mass %), BPS6574 (non-volatile component: 57 mass %), BPS8170 (non-volatile component: 36.5 mass %), BPS HS-1 (non-volatile component: 40 mass %).

[0111] Solvent-based adhesives (re-peelable) manufactured by Lion Specialty Chemicals include AS-325 (solid content concentration: 45 mass%), AS-375 (solid content concentration: 45 mass%), AS-409 (solid content concentration: 45 mass%), AS-417 (solid content concentration: 45 mass%), AS-425 (solid content concentration: 45 mass%), AS-455 (solid content concentration: 45 mass%), AS-665 (solid content concentration: 40 mass%), AS-1107 (solid content concentration: 43 mass%), and AS-4005 (solid content concentration: 45 mass%).

[0112] The acrylic adhesive used for the first thermal transfer layer 50 may be used together with a tackifier.

[0113] For example, this is because the chelation of the first thermal transfer layer 50 can be improved, unnecessary peeling can be suppressed, and the clarity of the recorded text can be improved. Examples of the tackifier include rosin glycerol ester, terpene phenolic resin, rosin ester, etc. Specific examples of the tackifier are not particularly limited, but examples include the following various tackifiers. These tackifiers can be used alone or in combination of two or more.

[0114] YS produced by YASUHARA CHEMICAL (Co., Ltd.) POLYSTER series of terpene phenolic resins include U130 (softening point: 130±5℃), U115 (softening point: 115±5℃), T160 (softening point: 160±5℃), T145 (softening point: 145±5℃), T130 (softening point: 130±5℃), T115 (softening point: 115±5℃), T100 (softening point: 100±5℃), T80 (softening point: 80±5℃), S145 (softening point: 145±5℃), G150 (softening point: 150±5℃), G125 (softening point: 125±5℃), N125 (softening point: 125±5℃), K125 (softening point: 125±5℃), and TH130 (softening point: 130±5℃).

[0115] ESTER GUM produced by Arakawa Chemical Industries, Ltd. includes AA-G (softening point (ring and ball method): 82-88°C), AA-L (softening point (ring and ball method): 82-88°C), AA-V (softening point (ring and ball method): 82-95°C), 105 (softening point (ring and ball method): 100-110°C), AT (viscosity: 20000-40000 mPa·s), H (softening point (ring and ball method): 68-75°C), and HP (softening point (ring and ball method): above 80°C).

[0116] GA-100 (softening point (ring and ball method): 100-110°C), AZ (softening point (ring and ball method): 950-105°C), C (softening point (ring and ball method): 117-127°C), D-125 (softening point (ring and ball method): 120-130°C), D-135 (softening point (ring and ball method): 130-140°C), D-160 (softening point (ring and ball method): 150-165°C), and KK (softening point (ring and ball method): above 165°C) of the PENSEL (registered trademark) series of rosin esters produced by Arakawa Chemical Industries, Ltd.

[0117] The softening point of the tackifier used for the first thermal transfer layer 50 is, for example, 60° C. or higher, and preferably 120° C. or lower.

[0118] The first thermal transfer layer 50 may contain any colorant. As the colorant, one or more various colorants corresponding to the color tone of the first thermal transfer layer 50 may be used. As the colorant, for example, a pigment may be used. In consideration of improving the weather resistance of the text, etc., the colorant used for the first thermal transfer layer 50 is preferably a pigment. For example, as a pigment for coloring the first thermal transfer layer 50 in black, carbon black is preferably used. There is no particular limitation as a specific example of carbon black, but the following various carbon blacks can be cited as examples. These carbon blacks can be used alone or in combination of two or more.

[0119] MA77 powder produced by Mitsubishi Chemical Co., Ltd. (LFF, DBP absorption: 68cm 3 / 100g), MA7 powder (LFF, DBP absorption: 66cm 3 / 100g), MA7 granules (LFF, DBP absorption: 65cm 3 / 100g), MA8 powder (LFF, DBP absorption: 57cm 3 / 100g), MA8 granules (LFF, DBP absorption: 51cm 3 / 100g), MA11 powder (LFF, DBP absorption: 64cm 3 / 100g), MA100 powder (LFF, DBP absorption: 100cm 3 / 100g), MA100 granules (LFF, DBP absorption: 95cm 3 / 100g), MA100R powder (LFF, DBP absorption: 100cm 3 / 100g), MA100R granular (LFF, DBP absorption: 95cm 3 / 100g), MA100S powder (LFF, DBP absorption: 100cm 3 / 100g), MA230 powder (LFF, DBP absorption: 113cm 3 / 100g), MA220 powder (LFF, DBP absorption: 93cm 3 / 100g), MA14 powder (LFF, DBP absorption: 73cm 3 / 100g).

[0120] Mitsubishi Chemical Co., Ltd. produced #3030B (furnace method, DBP absorption: 130cm 3 / 100g), #3040B (furnace method, DBP absorption: 114cm 3 / 100g), #3050B (furnace method, DBP absorption: 175cm 3 / 100g), #3230B (furnace method, DBP absorption: 140cm 3 / 100g), #3350B (furnace method, DBP absorption: 164cm 3 / 100g), #3400B (furnace method, DBP absorption: 175cm 3 / 100g).

[0121] #5500 (furnace method, DBP absorption: 155cm 3 / 100g), #4500 (furnace method, DBP absorption: 168cm 3 / 100g), #4400 (furnace method, DBP absorption: 135cm 3 / 100g), #4300 (furnace method, DBP absorption: 142cm 3 / 100g).

[0122] L (furnace method, DBP absorption: 120cm 3 / 100g), L6 (furnace method, DBP absorption: 126cm 3 / 100g).

[0123] Birla Carbon's CONDUCTEX (registered trademark) series of 975 (furnace method, 170cm 3 / 100g)、SC(furnace method, 115cm 3 / 100g).

[0124] XC72 (furnace method, DBP absorption: 174 cm 3 / 100g), 9A32 (furnace method, DBP absorption: 114cm 3 / 100g), 3700 (furnace method, DBP absorption: 111cm 3 / 100g).

[0125] DENKABLACK granular products (acetylene method, DBP absorption: 160cm 3 / 100g), FX-35 (acetylene method, DBP absorption: 220cm 3 / 100g), HS-100 (acetylene method, DBP absorption: 140cm 3 / 100g).

[0126] EC300J (vaporization method, DBP absorption: 360cm) in the KETJENBLACK (registered trademark) series produced by Lion Specialty Chemicals (Co., Ltd.) 3 / 100g), EC600DJ (vaporization method, DBP absorption: 495cm 3 / 100g).

[0127] The ratio of each component in the first thermal transfer layer 50 is not particularly limited. The ratio of the acrylic adhesive to 100 parts by mass of the epoxy resin is, for example, 30 parts by mass or more, preferably 40 parts by mass or more. The ratio of the acrylic adhesive to 100 parts by mass of the epoxy resin is, for example, 150 parts by mass or less, preferably 100 parts by mass or less. The ratio of the acrylic adhesive to 100 parts by mass of the epoxy resin is, for example, 30 parts by mass or more and 150 parts by mass or less, preferably 40 parts by mass or more and 100 parts by mass or less.

[0128] The ratio of the tackifier to 100 parts by mass of the epoxy resin is, for example, 3 parts by mass or more, preferably 5 parts by mass or more. The ratio of the tackifier to 100 parts by mass of the epoxy resin is, for example, 150 parts by mass or less, preferably 100 parts by mass or less. The ratio of the tackifier to 100 parts by mass of the epoxy resin is, for example, 3 parts by mass or more and 150 parts by mass or less, preferably 5 parts by mass or more and 100 parts by mass or less.

[0129] The ratio of the colorant such as carbon black to 100 parts by mass of the epoxy resin is, for example, 100 parts by mass or more, preferably 130 parts by mass or more. The ratio of the colorant to 100 parts by mass of the epoxy resin is, for example, 230 parts by mass or less, preferably 200 parts by mass or less. The ratio of the colorant to 100 parts by mass of the epoxy resin is, for example, 100 parts by mass or more and 230 parts by mass or less, preferably 130 parts by mass or more and 200 parts by mass or less.

[0130] Among the components contained in the first thermal transfer layer 50 , the components supplied in a liquid state dissolved or dispersed in an arbitrary solvent may be blended in an amount adjusted so that the ratio of the effective component falls within the above-mentioned range (the same applies hereinafter).

[0131] The first thermal transfer layer 50 can be formed, for example, by directly applying a coating obtained by dissolving or dispersing the above-mentioned components in an arbitrary solvent onto the fusion layer 70 and then drying the coating. Figure 5A and Figure 5BAs shown, the characters recorded on the printing tape 2 are color-coded. The first thermal transfer layer 50 is preferably formed directly on the fusion layer 70 in consideration of adjusting the adhesion between the first thermal transfer layer 50 and the fusion layer 70 and other layers for color coding.

[0132] The thickness of the first thermal transfer layer 50 can be arbitrarily set according to, for example, the specifications of the thermal transfer printer, etc. The thickness of the first thermal transfer layer 50 can be adjusted by the amount of the first thermal transfer layer 50 applied.

[0133] For example, the coating amount of the first thermal transfer layer 50 is 0.1 g / m 2 Above, preferably 0.5g / m 2 For example, the coating amount of the first thermal transfer layer 50 is 3.0 g / m 2 Below, preferably 2.5g / m 2 For example, the coating amount of the first thermal transfer layer 50 is expressed as 0.1 g / m 2 Above and 3.0g / m 2 Below, preferably 0.5g / m 2 Above and 2.5g / m 2 the following.

[0134] The specific thickness (before printing) of the first thermal transfer layer 50 is, for example, 0.05 μm or more, preferably 0.5 μm or more. The thickness of the first thermal transfer layer 50 is, for example, 3.0 μm or less, preferably 2.5 μm or less. The thickness of the first thermal transfer layer 50 can be, for example, 0.05 μm or more and 3.0 μm or less, preferably 0.5 μm or more and 2.5 μm or less. The thickness of the first thermal transfer layer 50 can be confirmed based on, for example, a SEM (Scanning Electron Microscope) image, a TEM (Transmission Electron Microscope) image, or the like of the thermal transfer recording medium 47.

[0135] (5) Middle layer 51

[0136] The intermediate layer 51 contains a thermoplastic elastomer. In particular, the intermediate layer 51 is preferably formed only of a thermoplastic elastomer. The thermoplastic elastomer forming the intermediate layer 51 preferably contains at least one of a styrene-based thermoplastic elastomer and an acetate-based thermoplastic elastomer.

[0137] Examples of styrene-based thermoplastic elastomers include styrene-butadiene-styrene block copolymers (SBS), styrene-ethylene·butylene-styrene block copolymers (SEBS), styrene-ethylene·propylene-styrene block copolymers (SEPS), styrene-ethylene / ethylene·propylene-styrene block copolymers (SEEPS), and styrene-isoprene-styrene block copolymers (SIS). Examples of acetate-based thermoplastic elastomers include ethylene-vinyl acetate copolymers (EVA).

[0138] The content of styrene in the thermoplastic elastomer of the intermediate layer 51 is, for example, 10% by mass or more and 70% by mass or less, preferably 15% by mass or more and 50% by mass or less. If the styrene content is too high, the rubber elasticity of the intermediate layer 51 is reduced, and there is a case where the adhesion to the first thermal transfer layer 50 and the second thermal transfer layer 52 cannot be maintained during low-temperature transfer, and the color of the text becomes turbid. If the styrene content is too low, the rubber elasticity of the intermediate layer 51 becomes too high, and there is a case where the second thermal transfer layer 52 cannot be peeled off during high-temperature transfer, resulting in turbidity in the color of the text.

[0139] The melt flow rate (hereinafter, may be simply described as "MFR") of the thermoplastic elastomer contained in the intermediate layer 51 is, for example, 1000 g / 10 min or less, preferably 400 g / 10 min or less. MFR can be obtained, for example, by the measurement method specified in ISO 1133-1:2011, and may be MFR at a temperature of 190°C and a load of 2.16 kg. Hereinafter, unless there is a specific description of the measurement conditions of MFR, the conditions are a temperature of 190°C and a load of 2.16 kg.

[0140] Thermoplastic elastomers with an MFR exceeding 400 g / 10 min tend to have an excessively strong affinity with the second thermal transfer layer 52. Therefore, there is a case where the second thermal transfer layer 52 cannot be peeled off during low-temperature transfer, and the color of the text becomes turbid. In addition, there is a case where the entire thermal transfer recording medium 47, that is, the base material layer 48, the welding layer 70, the first thermal transfer layer 50, the intermediate layer 51, and the second thermal transfer layer 52 are attached to the printing surface 31 of the printing tape 2. Thermoplastic elastomers with an MFR exceeding 400 g / 10 min have a low melt viscosity and high fluidity, so there is a case where the adhesion with respect to the first thermal transfer layer 50 and the second thermal transfer layer 52 cannot be maintained during low-temperature transfer, and the color of the text becomes turbid.

[0141] In contrast, if the thermoplastic elastomer has an MFR of 400 g / 10 min or less, the problems that may occur when using a thermoplastic elastomer having an MFR exceeding 400 g / 10 min can be suppressed. Furthermore, even if thermal transfer recording is performed continuously, the color tone on the printing surface 31 of the printing tape 2 is less likely to be turbid and is clearly separated into two colors, and no unnecessary peeling occurs, and text with excellent clarity can be recorded. In order to further improve these effects, the MFR of the thermoplastic elastomer is preferably 2.5 g / 10 min or less, and particularly preferably 2.3 g / 10 min or less, even within the above range.

[0142] The lower limit of MFR is not particularly limited, and even the thermoplastic elastomer with a measurement result of "No Flow" at the aforementioned temperature of 190°C and a load of 2.16 kg can be used. Specific examples of the thermoplastic elastomer are not particularly limited, but the following various thermoplastic elastomers can be listed, for example. These thermoplastic elastomers can be used alone or in combination of two or more.

[0143] H1521 (MFR: 2.3 g / 10 min), H1051 (MFR: less than 0.8 g / 10 min), H1052 (MFR: less than 13.0 g / 10 min), H1272 (MFR: NoFlow), P1083 (MFR: 3.0 g / 10 min), P1500 (MFR: 4.0 g / 10 min), P5051 (MFR: 3.0 g / 10 min), and P2000 (MFR: 3.0 g / 10 min) in the Tuftec (registered trademark) series of SEBS produced by Asahi Kasei Co., Ltd.

[0144] Tufprene (registered trademark) series SBS produced by Asahi Kasei Corporation: A (MFR: 2.6 g / 10 min), 125 (MFR: 4.5 g / 10 min), and 126S (MFR: 4.5 g / 10 min).

[0145] Asaprene (registered trademark) T series SBS produced by Asahi Kasei Corporation: T-411 (MFR: No Flow), T-432 (MFR: No Flow), T-437 (MFR: No Flow), T-438 (MFR: No Flow), and T-439 (MFR: No Flow).

[0146] The SEPS of SEPTON (registered trademark) series produced by Kuraray (Co., Ltd.) are 2002 (MFR: 70 g / 10 min), 2004F (MFR: 5 g / 10 min), 2005 (MFR: No Flow), 2006 (MFR: No Flow), 2063 (MFR: 7 g / 10 min), and 2104 (MFR: 0.4 g / 10 min). The MFR of these SEPS is measured under the conditions of temperature 230°C and load 2.16 kg.

[0147] Among the SEEPS of the SEPTON (registered trademark) series produced by Kuraray (Co., Ltd.), there are 4033 (MFR: <0.1 g / 10 min), 4044 (MFR: No Flow), 4055 (MFR: No Flow), 4077 (MFR: No Flow), and 4099 (MFR: No Flow). The MFR of these SEEPS is measured under the conditions of a temperature of 230°C and a load of 2.16 kg.

[0148] 5125 (MFR: 4 g / 10 min) and 5127 (MFR: 5 / 10 min) of the HYBRAR (registered trademark) series of vinyl SIS produced by Kuraray (Co., Ltd.).

[0149] Ultrasen (registered trademark) series EVA produced by Tosoh Co., Ltd. includes 514R (MFR: 0.41 g / 10 min), 515 (MFR: 2.5 g / 10 min), 510 (MFR: 2.5 g / 10 min), 510F (MFR: 2.5 g / 10 min), 520F (MFR: 2.0 g / 10 min), 540 (MFR: 3.0 g / 10 min), 540F (MFR: 3.0 g / 10 min). 0min), 537 (MFR: 8.5g / 10min), 537L (MFR: 8.5g / 10min), 537S-2 (MFR: 8.5g / 10min), 541 (MFR: 9.0g / 10mi n), 541L (MFR: 9.0g / 10min), 530 (MFR: 75g / 10min), 526 (MFR: 25g / 10min), 630 (MFR: 1.5g / 10min), 631 (M FR: 1.5g / 10min), 636 (MFR: 2.5g / 10min), 625 (MFR: 14g / 10min), 626 (MFR: 3.0g / 10min), 627 (MFR: 0.8g / 10min), 633 (MFR: 20g / 10min), 635 (MFR: 2.4g / 10min), 640 (MFR: 2.8g / 10min), 634 (MFR: 4.3g / 10min), 6 80 (MFR: 160g / 10min), 681 (MFR: 350g / 10min), 751 (MFR: 5.7g / 10min), 710 (MFR: 18g / 10min), 720 (MFR: 1 50g / 10min), 722 (MFR: 400g / 10min), 750 (MFR: 30g / 10min), 752 (MFR: 60g / 10min), 760 (MFR: 70g / 10min).

[0150] The intermediate layer 51 can be formed, for example, by applying a coating obtained by dissolving or dispersing a material for forming the intermediate layer 51 including at least a thermoplastic elastomer in an arbitrary solvent onto the first thermal transfer layer 50 and then drying the coating.

[0151] The thickness of the intermediate layer 51 can be arbitrarily set according to the specifications of the thermal transfer printer, for example. The thickness of the intermediate layer 51 can be adjusted by the coating amount of the intermediate layer 51. For example, the coating amount of the intermediate layer 51 is expressed as 0.1 g / m 2 Above, preferably 0.2 g / m 2 For example, the coating amount of the intermediate layer 51 is expressed as 2.0 g / m 2Below, preferably 1.5g / m 2 For example, the coating amount of the intermediate layer 51 is expressed as 0.1 g / m 2 Above and 2.0g / m 2 Below, preferably 0.2g / m 2 Above and 1.5g / m 2 the following.

[0152] The specific thickness (before printing) of the intermediate layer 51 is, for example, 0.05 μm or more, preferably 0.2 μm or more. The thickness of the intermediate layer 51 is, for example, 2.0 μm or less, preferably 1.5 μm or less. The thickness of the intermediate layer 51 can be, for example, 0.05 μm or more and 2.0 μm or less, preferably 0.2 μm or more and 1.5 μm or less. The thickness of the intermediate layer 51 can be confirmed based on, for example, a SEM (Scanning Electron Microscope) image, a TEM (Transmission Electron Microscope) image, or the like of the thermal transfer recording medium 47.

[0153] In addition, due to the limitation of coating accuracy, the thickness of the intermediate layer 51 may have errors depending on the measurement position. The coating amount and thickness of the intermediate layer 51 mentioned above may be values ​​including this error. For example, from 0.2 g / m 2 The intermediate layer 51 formed by the coating amount may also have a coating amount of 0.1 g / m 2 The coating amount forms an area of ​​thickness under the condition.

[0154] (6) Second thermal transfer layer 52

[0155] The second thermal transfer layer 52 can be formed of any thermoplastic resin, for example. Examples of the thermoplastic resin used for the second thermal transfer layer 52 include epoxy resin, polyester resin, polyolefin resin, etc. The thermoplastic resin can be appropriately selected according to the material of the printing ribbon 2, etc. When the first thermal transfer layer 50 is formed of epoxy resin, the second thermal transfer layer 52 is preferably also formed of epoxy resin.

[0156] By forming the second thermal transfer layer 52 from an epoxy resin, the adhesion force of the first thermal transfer layer 50 to the fusion layer 70 and the intermediate layer 51 and the adhesion force of the second thermal transfer layer 52 to the printing tape 2 can be counteracted. As a result, during low-temperature transfer, the first thermal transfer layer 50 and the intermediate layer 51 can be well separated to the substrate layer 48 side, and the second thermal transfer layer 52 can be well separated to the printing tape 2 side. Examples of the epoxy resin include various epoxy resins exemplified as the epoxy resin of the first thermal transfer layer 50. These epoxy resins can be used alone or in combination of two or more.

[0157] The second thermal transfer layer 52 may contain wax in addition to the thermoplastic resin. By containing wax, the first thermal transfer layer 50 and the intermediate layer 51 can be separated well to the substrate layer 48 side, and the second thermal transfer layer 52 can be separated well to the printing tape 2 side during low-temperature transfer.

[0158] As the wax, any wax having affinity and compatibility with thermoplastic resins such as epoxy resins can be used, for example, natural waxes such as carnauba wax, paraffin wax, and microcrystalline wax, and synthetic waxes such as Fischer-Tropsch wax can be used. Specific examples of the wax include, but are not particularly limited to, carnauba wax No. 1 flake, No. 2 flake, No. 3 flake, No. 1 powder, and No. 2 powder (all of which have a melting point of 80 to 86° C.) produced by Toyo Chemical Co., Ltd., paraffin waxes such as EMUSTAR-1155 (melting point: 69° C.), EMUSTAR-0135 (melting point: 60° C.), and EMUSTAR-0136 (melting point: 60° C.) produced by Nippon Seiwa Co., Ltd., microcrystalline waxes such as EMUSTAR-0001 (melting point: 84° C.) and EMUSTAR-042X (melting point: 84° C.) produced by Nippon Seiwa Co., Ltd., and Fischer-Tropsch waxes such as FNP-0090 (condensation point: 90° C.), SX80 (condensation point: 83° C.), FT-0165 (melting point: 73° C.), and FT-0070 (melting point: 72° C.) produced by Nippon Seiwa Co., Ltd. These waxes may be used alone or in combination of two or more.

[0159] The second thermal transfer layer 52 may contain any colorant. As the colorant, one or more kinds of colorants corresponding to the color tone of the second thermal transfer layer 52 may be used. As the colorant, for example, a pigment may be used. Considering the improvement of the weather resistance of the text, etc., the colorant used for the second thermal transfer layer 52 is preferably a pigment. For example, as a pigment for coloring the second thermal transfer layer 52 in red, the following various red pigments may be listed. These red pigments may be used alone or in combination of two or more.

[0160] CI Pigment Red 5, 7, 9, 12, 48 (Ca), 48 (Mn), 49, 52, 53, 53:1, 57 (Ca), 57:1, 97, 112, 122, 123, 149, 168, 177, 178, 179, 184, 202, 206, 207, 209, 242, 254, 255.

[0161] The ratio of each component in the second thermal transfer layer 52 is not particularly limited. The ratio of the wax to 100 parts by mass of the epoxy resin is, for example, 3 parts by mass or more, preferably 5 parts by mass or more. The ratio of the wax to 100 parts by mass of the epoxy resin is, for example, 11 parts by mass or less, preferably 9 parts by mass or less. The ratio of the wax to 100 parts by mass of the epoxy resin is, for example, 3 parts by mass or more and 11 parts by mass or less, preferably 5 parts by mass or more and 9 parts by mass or less.

[0162] The ratio of the colorant such as red pigment to 100 parts by mass of the epoxy resin is, for example, 70 parts by mass or more, preferably 80 parts by mass or more, and the ratio of the colorant such as red pigment to 100 parts by mass of the epoxy resin is, for example, 140 parts by mass or less, preferably 120 parts by mass or less.

[0163] The ratio of the coloring agent such as red pigment to 100 parts by mass of the epoxy resin is, for example, 70 parts by mass or more and 140 parts by mass or less, and preferably 80 parts by mass or more and 120 parts by mass or less.

[0164] The second thermal transfer layer 52 is formed, for example, by applying a coating obtained by dissolving or dispersing the above-mentioned components in an arbitrary solvent onto the intermediate layer 51 and then drying the coating.

[0165] The thickness of the second thermal transfer layer 52 can be arbitrarily set according to the specifications of the thermal transfer printer, for example. The thickness of the second thermal transfer layer 52 can be adjusted by the coating amount of the second thermal transfer layer 52. For example, the coating amount of the second thermal transfer layer 52 is expressed as 0.2 g / m 2 Above, preferably 1.0 g / m 2 For example, the coating amount of the second thermal transfer layer 52 is 7.0 g / m 2 Below, preferably 5.0g / m 2 For example, the coating amount of the second thermal transfer layer 52 is expressed as 0.2 g / m 2 Above and 7.0g / m 2 Below, preferably 1.0g / m 2 Above and 5.0g / m 2 the following.

[0166] As a specific thickness (before printing) of the second thermal transfer layer 52, for example, it is 0.05 μm or more, preferably 1.0 μm or more. The thickness of the second thermal transfer layer 52 is, for example, 7.0 μm or less, preferably 5.0 μm or less. The thickness of the second thermal transfer layer 52 can be, for example, 0.05 μm or more and 7.0 μm or less, preferably 1.0 μm or more and 5.0 μm or less. The thickness of the second thermal transfer layer 52 can be confirmed based on, for example, a SEM (Scanning Electron Microscope) image, a TEM (Transmission Electron Microscope) image, etc. of the thermal transfer recording medium 47.

[0167] In the thermal transfer recording medium 47, for example, there is a portion of the thermal transfer recording medium 47 to be applied to the thermal head 6 (see Figure 1 and Figure 3 ) is set to a lower energy and thermal transfer is performed at a relatively low temperature. In this case, in this embodiment, the second thermal transfer layer 52 softens and the adhesion relative to the substrate layer 48 is reduced. On the other hand, the adhesion between the first thermal transfer layer 50 and the second thermal transfer layer 52 is reduced. At this time, the welding layer 70 hardly softens due to its high softening point, thereby maintaining a high adhesion between the substrate layer 48 and the first thermal transfer layer 50. As a result, during thermal transfer, reverse transfer occurs in which the first thermal transfer layer 50 and the intermediate layer 51 remain on the substrate layer 48 side, and only the second thermal transfer layer 52 is thermally transferred to the printing surface 31 of the printing tape 2. Therefore, the text recorded on the printing surface 31 of the printing tape 2 becomes the color tone of the second thermal transfer layer 52, for example, red.

[0168] On the other hand, the thermal transfer recording medium 47 may be thermally transferred at a higher temperature by setting the energy applied to the thermal head 6 higher. In this case, the fusion layer 70 further softens, and the adhesion between the fusion layer 70 and the base layer 48 is greatly reduced. As a result, the entire thermal transfer layer, that is, the fusion layer 70, the first thermal transfer layer 50, the intermediate layer 51, and the second thermal transfer layer 52 are thermally transferred to the printing surface 31 of the printing tape 2 as a whole. The text recorded on the printing surface 31 of the printing tape 2 becomes the color tone of the first thermal transfer layer 50 located on the outermost layer after transfer, for example, black.

[0169] As a result, it is possible to record a pattern of two colors, for example, black and red, using a general-purpose thermal transfer printer that supports two-color recording.

[0170] Therefore, according to the present invention, a general-purpose thermal transfer printer that supports two-color recording can be used. Even if thermal transfer recording is performed continuously, the color tone is unlikely to be turbid and is clearly separated into two colors. There is no unnecessary peeling, and text with excellent clarity can be recorded.

[0171] [Introduction of Welding Layer 70 Based on Irreversible Change of Force]

[0172] exist Figure 6 , a thermal transfer recording medium 47 including a fusion bonding layer 70 is shown as an example of a thermal transfer recording medium (ink ribbon) capable of simultaneously recording characters in at least two colors with good clarity.

[0173] The specific chemical composition of the welding layer 70 includes at least one selected from the group consisting of polyamide resin, polyester resin, epoxy resin, phenolic resin and polyvinyl alcohol resin. The inventors of the present application have studied and implemented a thermal transfer recording medium having the same effect from another point of view, so it is described in detail below. More specifically, compared with Figure 6 In the above, attention is paid to the chemical composition of the components of the fusion bonding layer 70 , and in the following, attention is paid to the irreversible change of the interlayer adhesive force based on the control of the ultimate temperature of the thermal transfer recording medium 47 .

[0174] Figure 7 Yes means Figure 1 to Figure 4A , B is a diagram showing the relationship between the elapsed time in the heating step and the cooling step and the reaching temperature of the thermal transfer recording medium 47.

[0175] Figure 7 The horizontal axis of represents the elapsed time of the printing process of the printing device 1. t0 represents the start time of printing, t1 represents the end time of heating by the thermal head 6, and t2 represents the time when the ink ribbon peeling member 13 is reached. Figure 7 The vertical axis represents the arrival temperature of the thermal transfer recording medium 47. The arrival temperature of the thermal transfer recording medium 47 can be defined as the temperature of the thermal transfer recording medium 47 that changes due to external factors. The external factors may include, for example, heating by the thermal head 6, natural cooling of the thermal transfer recording medium 47 during transportation, and the like.

[0176] Reference Figure 7 In the printing device 1, the temperature output (temperature energy) of the thermal head 6 is controlled by the control circuit 22, so that the reaching temperature of the thermal transfer recording medium 47 can be controlled. For example, a relatively low first energy is applied to the thermal head 6 in the heating process. In this case, the temperature of the thermal transfer recording medium 47 is as shown by the first temperature curve 55 of the single-point dashed line, from the ambient temperature (for example, room temperature) T of the thermal transfer recording medium 47 to the temperature T of the thermal transfer recording medium 47. E It increases exponentially and reaches T R1 .

[0177] Reach temperature T R1 It can be defined as a temperature above the first temperature T1 and below the second temperature T2.

[0178] For example, the first temperature T1 is 60° C. to 120° C., preferably 70° C. to 90° C. For example, the second temperature T2 is 80° C. to 180° C., preferably 130° C. to 150° C. The reaching temperature T R1 The temperature can be set appropriately according to the output setting method of the thermal head 6 of the printing device 1 used. For example, the reaching temperature can be set in association with quantitative parameters such as the voltage, current, and power-on time supplied to the heating element 20 of the thermal head 6. In addition, the reaching temperature can be set in association with a relative value relative to a predetermined reference value (for example, the value before power-on is set to 0 (zero)).

[0179] On the other hand, in the heating process, a second energy relatively higher than the first energy is applied to the thermal head 6. In this case, the temperature of the thermal transfer recording medium 47 increases from the ambient temperature T to the ambient temperature T as shown by the second temperature curve 56 of the solid line. E And it increases exponentially to reach T R2 . Reach temperature T R2 It can also be defined as a temperature exceeding the second temperature T2.

[0180] After the heating process, the thermal transfer recording medium 47 is naturally cooled in the section until it reaches the ink ribbon peeling member 13 (see also Figure 3 and Figure 4A , B) In the cooling process, the temperature of the thermal transfer recording medium 47 is reduced from the reaching temperature T R1 and T R2 It decreases exponentially and reaches T P The reaching temperature at this time is T P It is the temperature at which a portion of the thermal transfer recording medium 47 is peeled off by the ribbon peeling member 13, and thus can be defined as the peeling temperature T P . Peeling temperature T P Preferably, the third temperature T3 is lower than the first temperature T1 (i.e., the first temperature T1 is higher than the third temperature T3), for example, 40°C to 90°C, preferably 60°C to 80°C. The first temperature T1, the second temperature T2, and the third temperature T3 can be appropriately set within the temperature range required for transferring the printing tape 2 in consideration of the chemical composition and physical properties of the ink of the thermal transfer recording medium 47.

[0181] The temperature curve (cooling curve) of the thermal transfer recording medium 47 in the cooling process eventually converges to a fixed temperature regardless of which heating control is performed in the heating process, as shown in the first temperature curve 55 or the second temperature curve 56. Therefore, in order to ensure a longer cooling process time (t1→t2), the peeling temperature T of the first temperature curve 55 or the second temperature curve 56 can be set to PIn order to extend the cooling process time, for example, the distance between the thermal head 6 and the ink ribbon stripping component 13 can be extended ( Figure 1 For example, the peeling distance L1 can be Figure 7 The state of the thermal transfer recording medium 47 after the heating process and the cooling process are performed according to the temperature change shown by the first temperature curve 55 is defined as the first state C1. Figure 7 The state of the thermal transfer recording medium 47 after the heating process and the cooling process are performed according to the temperature change shown by the second temperature curve 56 is defined as a second state C2.

[0182] In this way, in the printing device 1, by controlling the temperature output (temperature energy) of the thermal head 6, the starting temperature (ambient temperature T E ) and final temperature (peeling temperature T P ) is fixed, and the reaching temperature of the thermal transfer recording medium 47 is changed in various ways. Considering this temperature control, for example, by Figure 6 The temperature output of the thermal head 6 is controlled by adjusting the physical properties of the base layer 48, the back layer 49, the welding layer 70, the first thermal transfer layer 50, the intermediate layer 51 and the second thermal transfer layer 52 of the thermal transfer recording medium 47, thereby controlling the adhesion between the layers of the thermal transfer recording medium 47.

[0183] Figure 8 and Fig. 9 This is a diagram showing the relationship between the elapsed time in the heating step and the cooling step and the interlayer adhesive force of the thermal transfer recording medium 47 . Figure 8 The temperature of the thermal transfer recording medium 47 is set to Figure 6 The changes in the adhesive forces F when the first temperature curve 55 changes. Fig. 9 The temperature of the thermal transfer recording medium 47 is set to Figure 6 The changes in each adhesive force F when the second temperature curve 56 changes.

[0184] Figure 8 and Fig. 9 The horizontal axis of represents the elapsed time of the printing process of the printing device 1. t0 represents the start time of printing, t1 represents the end time of heating by the thermal head 6, and t2 represents the time when the ink ribbon peeling member 13 is reached. Figure 8 and Fig. 9 The vertical axis represents the magnitude of the adhesive force between the layers of the thermal transfer recording medium 47 .

[0185] exist Figure 8 and Fig. 9In the figure, the first adhesive force F1 between the first thermal transfer layer 50 and the second thermal transfer layer 52 of the thermal transfer recording medium 47 is represented by the solid line first adhesive force curve 57. In addition, the second adhesive force F2 between the base layer 48 and the first thermal transfer layer 50 is represented by the single-point second adhesive force curve 58. The first adhesive force F1 may include: the force when the bonding between the intermediate layer 51 and the second thermal transfer layer 52 is released, the force when the second thermal transfer layer 52 is broken inside, and the force when the intermediate layer 51 is broken inside. In addition, in the case where the components of the first thermal transfer layer 50 and the intermediate layer 51 are melted and mixed to form a mixed layer, the force when the bonding between the mixed layer and the second thermal transfer layer 52 is released may also be included. The second adhesive force F2 may include: the force when the bonding between the base layer 48 and the fusion layer 70 is released, the force when the bonding between the fusion layer 70 and the first thermal transfer layer 50 is released, the force when the first thermal transfer layer 50 is broken inside, and the force when the fusion layer 70 is broken inside.

[0186] Reference Figure 8 and Fig. 9 The first adhesive force F1 and the second adhesive force F2 both change with time by performing the heating process and the cooling process, regardless of the energy applied to the thermal head 6 during the heating process. More specifically, the first adhesive force F1 and the second adhesive force F2 decrease together with the passage of heating time, and the first adhesive force F1 and the second adhesive force F2 increase together with the passage of cooling time after heating.

[0187] The magnitude relationship between the first adhesive force F1 and the second adhesive force F2 before heating and after cooling varies according to the energy applied to the thermal head 6. Figure 8 As shown in FIG. 1 , when the energy applied to the thermal head 6 is relatively low, the second adhesive force F2 is greater than the first adhesive force F1 in either the case before heating or after cooling (the first state C1). Therefore, if peeling is performed in the first state C1, peeling occurs between the first thermal transfer layer 50 and the second thermal transfer layer 52 because the first adhesive force F1 is less than the second adhesive force F2, and the second thermal transfer layer 52 is transferred to the printing tape 2. On the other hand, in order to satisfy the condition that the first adhesive force F1 is less than the second adhesive force F2 after cooling, it is preferable to have at least a certain adhesive force F2 corresponding to the first state C1. Fig. 9 The cooling process is performed at a long time t3 at the intersection 59 of the first adhesive force curve 57 and the second adhesive force curve 58. This is because the thermal transfer recording medium 47 is sufficiently cooled and cold peeling can be performed reliably.

[0188] In addition, for example Fig. 9As shown, when the energy applied to the thermal head 6 is relatively high, the magnitude relationship between the first adhesive force F1 and the second adhesive force F2 is reversed before heating and after cooling (the second state C2). Before heating, the second adhesive force F2 is greater than the first adhesive force F1. On the other hand, after cooling (the second state C2), the second adhesive force F2 becomes smaller than the first adhesive force F1. That is, the first adhesive force F1 undergoes an irreversible change. Therefore, if peeling is performed in the second state C2, since the first adhesive force F1>the second adhesive force F2, peeling occurs between the base material layer 48 and the first thermal transfer layer 50, and the first thermal transfer layer 50 and the second thermal transfer layer 52 in the bonded state are transferred to the print tape 2. On the other hand, in order to satisfy the condition that the first adhesive force F1>the second adhesive force F2 after cooling, it is preferred that at least the adhesive force F1>the second adhesive force F2 be greater than the adhesive force F1. Fig. 9 The cooling process is performed at a long time t3 at the intersection 60 of the first adhesive force curve 57 and the second adhesive force curve 58. This is because the thermal transfer recording medium 47 is sufficiently cooled and cold peeling can be performed reliably.

[0189] The time t3 may be appropriately set so that the first adhesive force F1 < the second adhesive force F2 after the thermal transfer recording medium 47 heated by low energy cools down, and the first adhesive force F1 > the second adhesive force F2 after the thermal transfer recording medium 47 heated by high energy cools down. For example, it may be the time required to make the reaching temperature of the thermal transfer recording medium 47 lower than the third temperature T3 in either case of applying low energy or applying high energy. The peeling distance L1 (refer to Figure 1 ) is, for example, greater than 70 mm and less than 150 mm, preferably greater than 90 mm and less than 120 mm.

[0190] Thus, by utilizing the irreversible change of the first adhesive force F1 generated by the energy applied to the thermal head 6, it is possible to provide a thermal transfer recording medium 47 that can freely control the peeling position of the thermal transfer recording medium 47 and simultaneously record text in at least two colors with good clarity.

[0191] (1) Peeling Mode of Thermal Transfer Recording Medium 47

[0192] Figure 10 to Figure 17 47 is a diagram showing a peeled state of the thermal transfer recording medium 47. Figure 10 to Figure 17 , how the thermal transfer recording medium 47 is peeled off based on the magnitude relationship between the first adhesive force F1 and the second adhesive force F2 is described. Figure 10 to Figure 17 , the thermal transfer recording medium 47 lists a plurality of peeling modes. Figure 10 to Figure 17 The peeling modes are sequentially described as the first peeling mode to the eighth peeling mode. From the viewpoint of the energy supplied to the thermal head 6, it can be divided into Figure 10 to Figure 13The low energy peeling mode and Figure 14 to Figure 17 High energy peeling mode shown.

[0193] Figure 10 to Figure 13 is through Figure 7 The peeling mode is when peeling (thermal transfer) is performed in the first state C1 by heating control (applying low energy) of the first temperature curve 55. Fig.10 In the first peeling mode, the breaking strength (first adhesive force F1) between the intermediate layer 51 and the second thermal transfer layer 52 in the first state C1 is the smallest in the thermal transfer recording medium 47, and peeling occurs at their interface. Fig.11 In the second peeling mode, the breaking strength (first adhesive force F1) in the second thermal transfer layer 52 in the first state C1 is the smallest in the thermal transfer recording medium 47, and peeling occurs inside the second thermal transfer layer 52. Fig.12 In the third peeling mode, the breaking strength (first adhesive force F1) in the intermediate layer 51 in the first state C1 is the smallest in the thermal transfer recording medium 47, and peeling occurs inside the intermediate layer 51. Fig.13 In the fourth peeling mode, in the first state C1, the layer in contact with the second thermal transfer layer 52 is a mixed layer 61 formed by melting and mixing the components of the first thermal transfer layer 50 and the intermediate layer 51. In addition, the breaking strength (first adhesive force F1) between the mixed layer 61 and the second thermal transfer layer 52 is the smallest in the thermal transfer recording medium 47, and peeling occurs at their interface. Fig.10 The first peeling mode and Fig.13 The fourth peeling mode is interface failure, Fig.11 The second peeling mode and Fig.12 The third peeling mode is cohesive failure. Figure 10 to Figure 13 In any of the peeling modes, the second thermal transfer layer 52 is transferred to the printing tape 2 .

[0194] Figure 14 to Figure 17 is through Figure 7 The peeling mode in which peeling (thermal transfer) is performed in the second state C2 is performed by heating control (application of high energy) according to the second temperature curve 56 . Figure 14 to Figure 17 The peeling mode of can also be divided into at least two types, namely, interface failure and cohesive failure, similarly to the first to fourth peeling modes.

[0195] exist Fig.14 In the fifth peeling mode, the breaking strength (second adhesive force F2) between the base layer 48 and the fusion layer 70 in the second state C2 is the smallest in the thermal transfer recording medium 47, and peeling (interface failure) occurs at their interface. Fig.15In the sixth peeling mode, in the second state C2, the breaking strength (second adhesive force F2) between the fusion layer 70 and the first thermal transfer layer 50 is the smallest in the thermal transfer recording medium 47, and peeling (interfacial failure) occurs at their interface.

[0196] exist Fig.16 In the seventh peeling mode, the breaking strength (second adhesive force F2) in the first thermal transfer layer 50 is the smallest in the thermal transfer recording medium 47 in the second state C2, and peeling (cohesive failure) occurs inside the first thermal transfer layer 50. Fig.17 In the eighth peeling mode, in the second state C2, the breaking strength (second adhesive force F2) in the fusion layer 70 is the smallest in the thermal transfer recording medium 47, and peeling (cohesive failure) occurs inside the fusion layer 70.

[0197] exist Figure 14 to Figure 17 In any of the peeling modes, the first thermal transfer layer 50 and the second thermal transfer layer 52 in an adhered state are selectively transferred to the printing tape 2 .

[0198] The thermal transfer recording medium 47 is Figure 10 to Figure 17 Which peeling mode is broken can be confirmed, for example, by observing the cross section of the thermal transfer recording medium 47 after breaking. For example, it can be confirmed based on a SEM (Scanning Electron Microscope) image or a TEM (Transmission Electron Microscope) image of the thermal transfer recording medium 47 after breaking.

[0199] As described above, in the first to fourth peeling modes, the text recorded on the printing surface 31 of the printing tape 2 becomes the color tone of the second thermal transfer layer 52, such as red. In the fifth to eighth peeling modes, the text recorded on the printing surface 31 of the printing tape 2 becomes the color tone of the first thermal transfer layer 50, such as black.

[0200] Therefore, in order to provide a thermal transfer recording medium 47 capable of simultaneously recording text in at least two colors with good clarity, at least one of the first to fourth peeling modes is achieved during the heating control (low energy application) of the first temperature curve 55, and at least one of the fifth to eighth peeling modes is achieved during the heating control (high energy application) of the second temperature curve 56. To achieve these, the conditions of each layer of the thermal transfer recording medium 47 are studied from the following multiple viewpoints.

[0201] (2) Chemical Composition of Each Layer of Thermal Transfer Recording Medium 47

[0202] From the viewpoint of the chemical composition of each layer of the thermal transfer recording medium 47, the chemical composition of each layer of the base layer 48, the back layer 49, the fusion layer 70, the first thermal transfer layer 50, the intermediate layer 51, and the second thermal transfer layer 52 shown in the above-mentioned "Introduction of the fusion layer 70" is preferred. Of course, the thermal transfer recording medium 47 having this chemical composition has the fusion layer 70 including at least one selected from the group consisting of polyamide resin, polyester resin, epoxy resin, phenolic resin, and polyvinyl alcohol resin, and therefore Figure 7 Regardless of the temperature control shown, by performing temperature control under general conditions using a general thermal transfer printer, it is possible to simultaneously record text in at least two colors with good clarity.

[0203] In passing Figure 7 When thermal transfer is performed in the printing device 1 under the temperature control shown, other compositions besides the above-mentioned thermoplastic elastomer can be used as the intermediate layer 51. For example, the intermediate layer 51 may contain at least one of a polyolefin resin and a long-chain alkyl resin.

[0204] Examples of the polyolefin-based resin include SURFLEN (registered trademark) P-1000 manufactured by Mitsubishi Chemical Corporation.

[0205] Examples of the long-chain alkyl resin include 1010, 1010S, 1050, 1070, and 406 of the Piloil (registered trademark) series manufactured by Lion Specialty Chemicals Co., Ltd.

[0206] The fusion bonding layer 70 and the intermediate layer 51 including the resins exemplified above can also provide a thermal transfer recording medium 47 capable of simultaneously recording characters in at least two colors with good clarity.

[0207] (3) Solubility Parameter (SP Value) of Each Layer of Thermal Transfer Recording Medium 47

[0208] From the perspective of the physical properties of each layer of the thermal transfer recording medium 47, the relative relationship between the solubility parameter (SP value) and the softening point of the constituent components of each layer is focused. By adjusting the SP value and softening point of the constituent components of each layer, the interlayer adhesion and internal peeling of the thermal transfer recording medium 47 can be controlled. The closer the SP values ​​of the constituent components in contact with each other are, the easier it is to adhere (high affinity), and the greater the difference in SP values, the easier it is to peel off (low affinity). Therefore, by adjusting the balance between the SP value and the content rate of the constituent components of each layer of the thermal transfer recording medium 47, the peeling position in the thermal transfer recording medium 47 can be flexibly controlled. Thus, a thermal transfer recording medium 47 that can simultaneously record text in at least two colors with good clarity is provided.

[0209] Hereinafter, when the relative relationship (size relationship) of the SP value is expressed, the calculation conditions of the SP value of the comparison object are the same, for example, the SP value may be the HSP value (Hansen solubility parameter) or the SP value (Hildebrand solubility parameter). In addition, the calculation method of the SP value is not particularly limited, for example, it may be any of the methods for calculating the SP value according to the physical property value such as the method for obtaining the SP value based on the latent heat of evaporation, the method based on the Hildebrand Rule, the method based on the surface tension, the calculation method of Small, the calculation method of Fedors, the calculation method of Hansen, the calculation method of Hoy, etc., which are calculated according to the molecular structure. In addition, in the present invention, the SP value in the case of expressing the range of the SP value and the specific numerical value is the SP value (Hildebrand solubility parameter) except for special records.

[0210] Fig.18 This is a diagram for comparing the solubility parameters (SP values) of the constituent materials of the thermal transfer recording medium 47 according to one embodiment of the present invention.

[0211] Reference Fig.18 The first thermal transfer layer 50 is composed of at least a first material 62 and a second material 63. The first material 62 is a material having a relatively lower SP value and a lower softening point than the second material 63. The SP value of the first material 62 is, for example, 7.5 to 9.5, preferably 8.0 to 9.0. As the first material 62, the adhesive and the thickener exemplified as the components of the first thermal transfer layer 50 in the above-mentioned "Introduction of the welding layer 70" can be cited.

[0212] The second material 63 is a material having a relatively higher SP value and softening point than the first material 62. The SP value of the second material 63 is, for example, 9.0 to 12.0, preferably 10.0 to 11.0. The softening point of the second material 63 is, for example, 60° C. to 150° C., preferably 90° C. to 145° C. As the second material 63, the thermoplastic resins exemplified as the components of the first heat transfer layer 50 in the above-mentioned “Introduction of the welding layer 70” can be cited.

[0213] The weight ratio of the first material 62 and the second material 63 in the first thermal transfer layer 50 is, for example, 30 parts by mass or more, preferably 45 parts by mass or more of the first material 62 relative to 100 parts by mass of the second material 63. For example, the first material 62 is 300 parts by mass or less, preferably 200 parts by mass or less relative to 100 parts by mass of the second material 63. For example, the first material 62 is 30 parts by mass or more and 300 parts by mass or less, preferably 45 parts by mass or more and 200 parts by mass or less relative to 100 parts by mass of the second material 63.

[0214] The intermediate layer 51 is composed of at least a third material 64. The third material 64 is a material having a relatively low SP value compared to the second material 63 and the fifth material 66 (described later). The SP value of the third material 64 is, for example, 7.5 to 10.0, preferably 8.0 to 9.0. As the third material 64, in addition to the thermoplastic elastomer exemplified in the above-mentioned "Introduction of the welding layer 70", polyolefin resins and long-chain alkyl resins can also be listed.

[0215] The second heat transfer layer 52 is composed of at least a fourth material 65 and a fifth material 66 .

[0216] The fourth material 65 is a material having a relatively higher SP value and softening point than the fifth material 66. The SP value of the fourth material 65 is, for example, 9.0 to 12.0, preferably 10.0 to 11.0. The softening point of the fourth material 65 is, for example, 60° C. to 150° C., preferably 90° C. to 145° C. As the fourth material 65, the thermoplastic resins exemplified as the components of the second thermal transfer layer 52 in the above-mentioned “Introduction of the welding layer 70” can be cited.

[0217] The fifth material 66 is a material having a relatively lower SP value and softening point than the fourth material 65. The SP value of the fifth material 66 is, for example, 7.5 to 9.5, preferably 8.0 to 9.0. The melting point of the fifth material 66 is, for example, 60° C. to 120° C., preferably 65° C. to 100° C. As the fifth material 66, the wax exemplified as a component of the second thermal transfer layer 52 in the above-mentioned “Introduction of the welding layer 70” can be cited.

[0218] The weight ratio of the fourth material 65 and the fifth material 66 in the second thermal transfer layer 52 is, for example, 3 parts by mass or more, preferably 5 parts by mass or more, of the fifth material 66 relative to 100 parts by mass of the fourth material 65. For example, the fifth material 66 is 11 parts by mass or less, preferably 9 parts by mass or less, of the fourth material 65 relative to 100 parts by mass. For example, the fifth material 66 is 3 parts by mass or more and 11 parts by mass or less, preferably 5 parts by mass or more and 9 parts by mass or less, of the fourth material 65 relative to 100 parts by mass.

[0219] The welding layer 70 is composed of at least the sixth material 67. The sixth material 67 is a material having a relatively higher SP value and softening point than the material of the base material layer 48 and the second material 63. The SP value of the sixth material 67 is, for example, 9.0 to 14.0, preferably 12.0 to 14.0. As the sixth material 67, at least one selected from the group consisting of polyamide resin, polyester resin, epoxy resin, phenolic resin, and polyvinyl alcohol resin listed in the above-mentioned "Introduction of welding layer 70" can be cited.

[0220] Examples of the material of the base material layer 48 include the resin films exemplified in the above-mentioned “Introduction of the welding layer 70 ”, capacitor paper, thin paper such as glassine paper, and cellophane.

[0221] To summarize the relative relationship between the SP value and the softening point, first, regarding the SP value, the SP value of the first material 62, the third material 64, and the fourth material 65 is smaller than the SP value of the second material 63, the fifth material 66, and the sixth material 67. In addition, the SP value of the second material 63 and the fifth material 66 is smaller than the SP value of the sixth material 67. Regarding the softening point, the softening point of the first material 62, the fourth material 65, and the fifth material 66 is lower than the softening point of the second material 63 and the third material 64. In addition, the softening point of the second material 63 and the third material 64 is lower than the softening point of the sixth material 67, and the softening point of the third material 64 and the sixth material 67 is lower than the softening point of the base material layer 48.

[0222] Fig.19 This is a diagram showing the relationship between the type of material constituting a part of the thermal transfer recording medium 47 and the magnitude of the solubility parameter.

[0223] As described above, the names of materials that can be used as the first to sixth materials 62 to 67 are exemplified, but as long as the relative relationship (size relationship) of the SP values ​​in the thermal transfer recording medium 47 is as described above, there is no particular limitation on the materials used. Fig.19 At this time, it is considered that the closer the SP values ​​between materials are, the easier it is to adhere, and the greater the difference in SP values ​​is, the easier it is to peel.

[0224] For example, regarding the first thermal transfer layer 50, terpene phenolic resin may be selected as the first material 62, and epoxy resin may be selected as the second material 63. For example, regarding the intermediate layer 51, thermoplastic elastomer, polyolefin, etc. may be selected as the third material 64. For example, regarding the second thermal transfer layer 52, wax may be selected as the fourth material 65, and epoxy resin may be selected as the fifth material 66. For example, regarding the welding layer 70, polyamide resin with a particularly high SP value may be selected as the sixth material 67.

[0225] As long as the SP values ​​are combined as above, Figure 7 When the heating control of the first temperature curve 55 is performed (low energy is applied), at least one of the first to fourth peeling modes is achieved, and when the heating control of the second temperature curve 56 is performed (high energy is applied), at least one of the fifth to eighth peeling modes is achieved.

[0226] For example, the thermal head 6 (see Figure 1 and Figure 3) is set low and thermal transfer is performed at a relatively low temperature. In this case, in this embodiment, the second thermal transfer layer 52 softens and the adhesion to the substrate layer 48 is reduced. On the other hand, the adhesion between the first thermal transfer layer 50 and the second thermal transfer layer 52 is reduced. At this time, the welding layer 70 hardly softens due to its high softening point, thereby maintaining a high adhesion between the substrate layer 48 and the first thermal transfer layer 50. This is because the SP value of the sixth material 67 of the welding layer 70 is high, so that the cohesive force is likely to increase and the softening point is likely to increase. As a result, during thermal transfer, reverse transfer occurs in which the first thermal transfer layer 50 and the intermediate layer 51 remain on the side of the substrate layer 48, and only the second thermal transfer layer 52 is thermally transferred to the printing surface 31 of the printing tape 2. Therefore, the text recorded on the printing surface 31 of the printing tape 2 becomes the color tone of the second thermal transfer layer 52, for example, red. That is, in the low-temperature transfer, at least one of the first to fourth peeling modes can be achieved.

[0227] On the other hand, in the thermal transfer recording medium 47, the energy applied to the thermal head 6 is set high, and thermal transfer is performed at a higher temperature. In this case, the fusion layer 70 is further softened, for example, the adhesion between the fusion layer 70 and the base layer 48 is greatly reduced. As a result, the entire thermal transfer layer, that is, the fusion layer 70, the first thermal transfer layer 50, the intermediate layer 51 and the second thermal transfer layer 52 are thermally transferred to the printing surface 31 of the printing tape 2 as a whole. The text recorded on the printing surface 31 of the printing tape 2 becomes the color tone of the first thermal transfer layer 50 located on the outermost layer after transfer, for example, black. That is, in the high-temperature transfer, at least one of the fifth peeling mode to the eighth peeling mode can be achieved. As a result, it is possible to improve the thermal transfer recording medium 47 that can simultaneously record text of two colors with good clarity.

[0228] Example

[0229] Hereinafter, the present invention will be further described based on experimental examples, but the structure of the present invention is not limited to these examples.

[0230] [Coating material for first thermal transfer layer (I)]

[0231] The components shown in Table 1 below were dissolved in a mixed solvent of toluene and methyl ethyl ketone (MEK) at a mass ratio of 1 / 4 to prepare a first thermal transfer layer coating (I) having a solid content concentration of 22.5 mass %.

[0232] The ratio of the active ingredient in the acrylic adhesive was 80 parts by mass per 100 parts by mass of the epoxy resin.

[0233] [Table 1]

[0234] Element Mass Epoxy resin 100 Acrylic adhesive 200 Tackifier 28.3 Carbon Black 166.7

[0235] The components in the table are as follows.

[0236] Epoxy resin: JER1007 produced by Mitsubishi Chemical Co., Ltd. (basic solid type, softening point (ring and ball method): 128°C, number average molecular weight Mn: about 2900, SP value: 9.5 to 11.5)

[0237] Acrylic adhesive: AS-665 manufactured by LION SPECIALTY CHEMICALS (Inc.) (solid content concentration: 40% by mass, SP value: 8.0 to 9.5)

[0238] Tackifier: terpene phenolic resin, YS POLYSTER T80 produced by YASUHARA CHEMICAL (Co., Ltd.) (softening point: 80±5°C, SP value: 8.0-9.0)

[0239] Carbon black: MA100 powder produced by Mitsubishi Chemical Co., Ltd. (LFF, DBP absorption: 100cm 3 / 100g)

[0240] [Coating for welding layer (1)]

[0241] A polyamide resin (Tohmide 1315 manufactured by T&K TOKA Co., Ltd., SP value: 13.60, softening point: 130±5°C) was dissolved in a mixed solvent of toluene and methyl ethyl ketone (MEK) in a mass ratio of 1 / 1 to prepare a welding layer coating (1) having a solid content concentration of 10% by mass.

[0242] [Paint for welding layer (2)]

[0243] A polyvinyl alcohol-based resin (DENKA POVAL B-05 manufactured by DENKA Corporation, SP value: 12.60, softening point: 200° C.) was dissolved in water to prepare a welding layer coating material (2) having a solid content concentration of 10% by mass.

[0244] [Paint for welding layer (3)]

[0245] A phenolic resin (PHENOLITE TD-2090 manufactured by DIC Corporation, SP value: 11.30, softening point: 117-123°C) was dissolved in a mixed solvent of toluene and methyl ethyl ketone (MEK) in a mass ratio of 1 / 1 to prepare a welding layer coating (3) having a solid content concentration of 10% by mass.

[0246] [Paint for welding layer (4)]

[0247] A phenolic resin (JER1001 manufactured by Mitsubishi Chemical Corporation, SP value: 10.90, softening point (ring and ball method): 64°C) was dissolved in a mixed solvent of toluene and methyl ethyl ketone (MEK) in a mass ratio of 1 / 1 to prepare a welding layer coating (4) having a solid content concentration of 10% by mass.

[0248] [Paint for welding layer (5)]

[0249] A polyester resin (VYLON GK-360 manufactured by Toyobo Co., Ltd., SP value: 9.30, glass transition temperature: 56°C) was dissolved in a mixed solvent of toluene and methyl ethyl ketone (MEK) in a mass ratio of 1 / 1 to prepare a welding layer coating (5) having a solid content concentration of 10% by mass.

[0250] The material names, SP values, and softening points of the welding layer coating materials (1) to (5) are summarized in Table 2. The mixing ratio of the constituent components is omitted because the solid content / solvent is 10 / 90 for the intermediate layer coating materials (1) to (5).

[0251] [Table 2]

[0252]

[0253] [Coating for intermediate layer (1)]

[0254] A thermoplastic elastomer (Tuftec H1521, SEBS, MFR: 12.3 g / 10 min, styrene content 18% by mass, SP value: 7.5-9.0, manufactured by Asahi Kasei Corporation) was dissolved in a mixed solvent of toluene and hexane in a mass ratio of 1 / 1 to prepare a coating (1) for an intermediate layer having a solid content concentration of 10% by mass.

[0255] [Coating for intermediate layer (2)]

[0256] The intermediate layer coating (2) was prepared in the same manner as the intermediate layer coating (1) except that the same amount of Tuftec H1517 (SEBS, MFR: less than 3.0 g / 10 min, styrene content 43% by mass, SP value: 7.5 to 9.0) manufactured by Asahi Kasei Corporation was added as the thermoplastic elastomer. The solid content concentration was 10% by mass.

[0257] [Coating for intermediate layer (3)]

[0258] The intermediate layer coating material (3) was prepared in the same manner as the intermediate layer coating material (1) except that the same amount of Tuftec H1272 (SEBS, MFR: No Flow, styrene content 35% by mass, SP value: 7.5 to 9.0) manufactured by Asahi Kasei Corporation was added as the thermoplastic elastomer. The solid content concentration was 10% by mass.

[0259] [Coating for intermediate layer (4)]

[0260] The intermediate layer coating (4) was prepared in the same manner as the intermediate layer coating (1) except that the same amount of Tuftec H1221 (SEBS, MFR: less than 4.5 g / 10 min, styrene content 12 mass %, SP value: 7.5 to 9.0) manufactured by Asahi Kasei Corporation was added as the thermoplastic elastomer. The solid content concentration was 10 mass %.

[0261] [Coating for intermediate layer (5)]

[0262] The intermediate layer coating (5) was prepared in the same manner as the intermediate layer coating (1) except that the same amount of Tuftec H1043 (SEBS, MFR: less than 2.0 g / 10 min, styrene content 67 mass %, SP value: 7.5 to 9.0) manufactured by Asahi Kasei Corporation was added as the thermoplastic elastomer. The solid content concentration was 10 mass %.

[0263] [Coating for intermediate layer (6)]

[0264] The intermediate layer coating (6) was prepared in the same manner as the intermediate layer coating (1) except that the same amount of Tufprene A (SBS, MFR: 2.6 g / 10 min, styrene content 40 mass %, SP value: 7.5 to 9.0) manufactured by Asahi Kasei Corporation was added as the thermoplastic elastomer. The solid content concentration was 10 mass %.

[0265] [Coating for intermediate layer (7)]

[0266] The intermediate layer coating (7) was prepared in the same manner as the intermediate layer coating (1) except that the same amount of Ultrasen 634 (EVA, MFR: 4.3 g / 10 min, SP value: 7.5 to 9.0) manufactured by Tosoh Corporation was added as the thermoplastic elastomer. The solid content concentration was 10% by mass.

[0267] [Coating for intermediate layer (8)]

[0268] The intermediate layer coating (8) was prepared in the same manner as the intermediate layer coating (1) except that the same amount of Ultrasen 722 (EVA, MFR: 400 g / 10 min, SP value: 7.5 to 9.0) manufactured by Tosoh Corporation was added as the thermoplastic elastomer. The solid content concentration was 10% by mass.

[0269] [Coating for intermediate layer (9)]

[0270] The intermediate layer coating (9) was prepared in the same manner as the intermediate layer coating (1) except that the same amount of Ultrasen 725 (EVA, MFR: 1000 g / 10 min, SP value: 7.5 to 9.0) manufactured by Tosoh Corporation was added as the thermoplastic elastomer. The solid content concentration was 10% by mass.

[0271] [Coating for intermediate layer (10)]

[0272] The intermediate layer coating (10) was prepared in the same manner as the intermediate layer coating (1) except that the same amount of Ultrasen 684 (EVA, MFR: 2000 g / 10 min, SP value: 7.5 to 9.0) manufactured by Tosoh Corporation was added as the thermoplastic elastomer. The solid content concentration was 10% by mass.

[0273] [Coating for intermediate layer (11)]

[0274] An intermediate layer coating (11) was prepared in the same manner as the intermediate layer coating (1) except that a modified polyolefin resin (SURFLEN (registered trademark) P-1000 manufactured by Mitsubishi Chemical Corporation, SP value: 7.5 to 8.5) was added in the same amount instead of the thermoplastic elastomer. The solid content concentration was 10% by mass.

[0275] The material names, MFRs, and styrene contents of the intermediate layer coatings (1) to (11) are summarized in Table 3. The mixing ratios of the constituent components are omitted because the intermediate layer coatings (1) to (11) are all solid content / toluene / hexane = 10 / 45 / 45.

[0276] [Table 3]

[0277]

[0278] [Coating material for second thermal transfer layer (I)]

[0279] The components shown in Table 4 below were dissolved in a mixed solvent of toluene and MEK at a mass ratio of 1 / 4 to prepare a second thermal transfer layer coating (I) having a solid content concentration of 28% by mass.

[0280] [Table 4]

[0281] Element Mass Epoxy resin 100 wax 7.1 Red Pigment 92.9

[0282] The components in the table are as follows.

[0283] Epoxy resin: JER1004 produced by Mitsubishi Chemical Co., Ltd. (basic solid type, softening point (ring and ball method): 97°C, number average molecular weight Mn: about 1650, SP value: 10.0 to 11.0)

[0284] Wax: Carnauba wax No. 2 powder produced by Toyo Komei Co., Ltd. (melting point: 80-86°C, SP value: 7.0-9.0)

[0285] Red pigment: CI Pigment Red 53:1 (SYMULER (registered trademark) LakeRed C-102 produced by DIC Corporation)

[0286] [Experimental Examples 1 to 21]

[0287] (1) Production of thermal transfer recording media

[0288] First, a PET film with a thickness of 4.5 μm was prepared as a substrate layer. Next, a film with a solid content of 0.1 g / m2 per unit area made of a silicone resin was formed on the side (back side) opposite to the surface on which the thermal transfer layer was formed. 2 Next, any one of the previously prepared welding layer coating materials is applied to the surface of the substrate layer and then dried to form a coating having a solid content per unit area of ​​0.4 g / m 2 Next, the first thermal transfer layer coating prepared previously was applied to the surface of the welding layer and then dried to form a solid content per unit area of ​​1.7 g / m 2 Next, any of the intermediate layer coatings prepared previously is applied on the first thermal transfer layer as required and then dried to form an intermediate layer. Regarding the amount of intermediate layer coating applied, the solid content per unit area in Experimental Examples 1 to 16 is 1 g / m 2 , in Experimental Examples 18 to 21, they are shown in Table 9 below. Next, the second thermal transfer layer coating (I) prepared previously was applied on the intermediate layer or the first thermal transfer layer and dried to form a solid content per unit area of ​​2.5 g / m 2 The compositions of the respective layers of the thermal transfer recording media obtained in Experimental Examples 1 to 21 are shown in Tables 5 to 9 below. In the table, NF in the column of the binder of the intermediate layer means No Flow.

[0289] (2) Evaluation

[0290] (2-1) Continuous Recording Evaluation

[0291] The thermal transfer recording medium produced in each experimental example was cut into a ribbon of a predetermined width, wound into a roll, and set in a thermal transfer printer (a prototype printer manufactured by Brother Industries, Ltd.). The main specifications of the thermal transfer printer are as follows.

[0292]

[0293] Next, in an environment with an outside temperature of 25°C, the energy value pre-set in the thermal transfer printer to be applied to the thermal head was set to low energy (0.25mJ / dot: 25V (0.34W / dot) / 750μsec, black) or high energy (0.34mJ / dot: 25V (0.34W / dot) / 1000μsec, red), and a 70mm square solid image was continuously recorded 20 times on the surface of a variable information printing label material (polyester film (white glossy), FR1415-50 produced by LINTEC Co., Ltd., SP value: 10.7, softening point: 240°C). If a little turbidity was observed during the recording, the continuous printing was terminated at that moment, and the number of times of printing in black or red was recorded as the number of continuous printings. In the evaluation, the experimental example in which black was printed even 20 times had excellent continuous printing performance of more than 20 times, and the experimental example in which turbidity was generated less than three times was considered to be insufficient for practical use. Tables 5 to 9 show the results.

[0294] (2-2) Evaluation of recording clarity

[0295] The thermal transfer recording medium manufactured in each experimental example was cut into an ink ribbon of a specified width, wound into a roll, and placed in a thermal transfer printer (a prototype printer produced by Brother Industries, Ltd.) of the same specification as (2-1). Next, in an environment with an outside temperature of 25°C, the energy value pre-set in the thermal transfer printer and applied to the thermal head was set to low energy (0.25mJ / dot: 25V (0.34W / dot) / 750μsec, black) or high energy (0.34mJ / dot: 25V (0.34W / dot) / 1000μsec, red), and a bar code was recorded on the surface of a variable information printing label material (polyester film (white glossy), FR1415-50 produced by LINTEC Co., Ltd., SP value: 10.7, softening point: 240°C). The recorded barcodes were read using a barcode verifier (Laser Sampling Elite IS manufactured by MUNAZO Co., Ltd.) to determine the decodability level specified in the American National Standards Institute standard (ANSI X3.182-1990), and the clarity of the recording was evaluated using the following criteria.

[0296] 0: The decodability level of both black and red is A [excellent] or B [good].

[0297] △: The decodability level of either black or red is C [good], and the other is C [good] or higher.

[0298] ×: The decodability level of at least one of black and red is D [pass] or F [fail].

[0299] The results are shown in Tables 5 to 9. In addition, among Experimental Examples 1 to 17, Experimental Examples 1 to 16 and Experimental Examples 18 to 21 may be Examples, and Experimental Example 17 may be a Comparative Example.

[0300] (2-3) Observation of fracture position

[0301] The thermal transfer recording medium manufactured in each experimental example was cut into a ribbon of a predetermined width, wound into a roll, and set in a thermal transfer printer (a prototype printer manufactured by Brother Industries, Ltd.) with the same specifications as (2-1). Next, in an environment with an outside temperature of 25°C, the energy values ​​pre-set in the thermal transfer printer to be applied to the thermal head were set to low energy (0.25 mJ / dot: 25 V (0.34 W / dot) / 750 μsec, reaching a temperature T R1 :80℃、black) and high energy (0.34mJ / dot:25V(0.34W / dot) / 1000μsec、reaching temperature T R2: 140°C, red), a 70 mm square solid image is recorded on the surface of a variable information printing label material (polyester film (white · glossy), FR1415-50 produced by LINTEC (Co., Ltd.), SP value: 10.7, softening point: 240°C). In any case, the peeling distance of the thermal transfer printer is ensured to be 110 mm, so the peeling process is carried out after sufficient cooling (below 60°C). A transmission electron microscope (TEM: HT7820 produced by Hitachi High-Tech Co., Ltd., accelerating voltage 100 kV) is used to observe the cross-section of the obtained solid image. In each of the black transfer and the red transfer, confirm where the thermal transfer recording medium has broken. The break position is distinguished by the peeling pattern as described below.

[0302] First peeling mode: between the middle layer and the second thermal transfer layer (interface damage reference Fig.10 )

[0303] Second peeling mode: Inside the second thermal transfer layer (cohesion failure reference Fig.11 )

[0304] The third peeling mode: inside the middle layer (cohesion failure reference Fig.12 )

[0305] Fourth peeling mode: between the mixed layer and the second thermal transfer layer (interface damage reference Fig.13 )

[0306] Fifth peeling mode: between the substrate layer and the weld layer (interface damage reference Fig.14 )

[0307] The sixth peeling mode: between the fusion layer and the first thermal transfer layer (interface damage reference Fig.15 )

[0308] The seventh peeling mode: the inside of the first thermal transfer layer (cohesion failure refers to Fig.16 )

[0309] The eighth peeling mode: Inside the weld layer (cohesion failure, see Fig.17 )

[0310] The results are shown in Tables 5 to 9. In Tables 5 to 9, only the circled numbers are used to indicate the first to eighth peeling modes, respectively. In addition, in Tables 5 to 9, when multiple peeling modes are shown, it means that different peeling modes are generated in the in-plane direction of the thermal transfer recording medium. In addition, since Experimental Examples 6 and 17 do not have a layer structure with an intermediate layer, the peeling modes in the lower part of Table 6 strictly speaking generate different peeling modes from the first to the eighth peeling modes. Fig.11 and Fig.13 The cohesive failure in the state where the intermediate layer 51 is omitted.

[0311] [Table 5]

[0312]

[0313]

[0314] [Table 6]

[0315]

[0316]

[0317] [Table 7]

[0318]

[0319] [Table 8]

[0320]

[0321]

[0322] [Table 9]

[0323]

[0324]

[0325] According to the comparison between Experimental Examples 1 to 16 in Tables 5 to 8 and Experimental Example 17, for example, referring to Fig.17 It can be seen that by adjusting the balance of the SP values ​​of the constituent components of the fusion layer, the first thermal transfer layer, the second thermal transfer layer, and the intermediate layer, a desired peeling pattern can be achieved. As a result, even if thermal transfer recording is performed continuously, the color tone is not easily turbid and is clearly separated into two colors, and no unnecessary peeling occurs, and a thermal transfer recording medium can be obtained that can record text with excellent clarity.

[0326] Comparison of Experimental Examples 1 to 4 with Experimental Example 5 shows that the SP value of the fusion layer is preferably higher than the SP value of the base layer (=10.7) and the SP value of the epoxy resin of the first thermal transfer layer (=10.0 to 11.0). This allows continuous recording of more than 10 times.

[0327] It is known from the comparison between Experimental Example 1 and Experimental Example 6 that it is preferable to provide an intermediate layer between the first thermal transfer layer and the second thermal transfer layer. This can provide a thermal transfer recording medium having both excellent continuous recording performance and high resolution.

[0328] Comparison between Experimental Examples 7 to 15 and Experimental Example 16 shows that, in order to further improve the continuous recording property and the resolution, it is preferable to use a thermoplastic elastomer as the intermediate layer.

[0329] In addition, according to the results of Experimental Examples 1, 7 to 15, it can be seen that the thermoplastic elastomer forming the intermediate layer is preferably EVA, SBS, SEBS, etc. Moreover, in view of further improving the continuous recording performance, the thermoplastic elastomer preferably has an MFR of 1000 g / 10 min or less at a temperature of 190° C. and a load of 2.16 kg, more preferably 400 g / 10 min or less, particularly preferably 2.5 g / 10 min or less, and most preferably 2.3 g / 10 min or less.

[0330] According to Experimental Example 1 and Experimental Examples 18 to 21, it is known that even if the coating amount of the intermediate layer is changed, practically sufficient continuous recording performance and clarity can be achieved. It is known that the continuous recording performance and clarity of Experimental Examples 1, 19 and 20 among Experimental Examples 1 and Experimental Examples 18 to 21 are particularly excellent. The intermediate layer of the layers constituting the thermal transfer recording medium of Experimental Examples 1, 19 and 20 is the thinnest (the coating amount is small) and the thickness (coating amount) of the intermediate layer is a size that can fully detect the effect of the introduction of the intermediate layer.

[0331] In other words, in Experiment 21, the middle layer of the layers constituting the thermal transfer recording medium is not the thinnest but relatively thick, so the area to be transferred (excess peeling) becomes larger, thereby reducing the clarity. Generally, it can be considered that if the thickness of the layer on the side close to the heat source among the adjacent layers is increased as in Experiment 21, the reaching temperature at the interface between the layer on one side and the layer on the other side will decrease, thereby reducing the transfer area. However, at the interface between the middle layer and the second thermal transfer layer, when the reaching temperature of the interface decreases, the middle layer-second thermal transfer layer ( Figure 6 As a result, it is believed that the adhesion between the label material and the second thermal transfer layer (between "51" and "52") is maintained at a low level. Figure 6 Compared with the bonding force between "2" and "52"), the bonding force between the intermediate layer and the second thermal transfer layer becomes relatively low, and a break occurs between the intermediate layer and the second thermal transfer layer, thereby increasing the excess peeling.

[0332] On the other hand, in Experimental Example 18, the intermediate layer was the thinnest among the layers constituting the thermal transfer recording medium, but the coating amount was 0.1 g / m 2 Such a small amount cannot fully realize the original function of the intermediate layer, and it is confirmed that both the continuous recording property and the resolution are reduced.

[0333] Explanation of symbols

[0334] 1: Printing device

[0335] 2: Printing tape

[0336] 3: Ink ribbon

[0337] 6: Thermal head

[0338] 20: Heating element

[0339] 31: Printing surface

[0340] 32: Back

[0341] 35: Base material layer

[0342] 36: First ink layer

[0343] 37: Second ink layer

[0344] 42: Part 1

[0345] 43: Part 2

[0346] 44: Printing pattern

[0347] 45: Red pattern

[0348] 46: Black pattern

[0349] 47: Thermal transfer recording media

[0350] 48: Base material layer

[0351] 50: First thermal transfer layer

[0352] 51: Middle layer

[0353] 52: Second thermal transfer layer

[0354] 61: Mixed Layer

[0355] 62: First Material

[0356] 63: Second Material

[0357] 64: Third Material

[0358] 65: Fourth Material

[0359] 66: Fifth Material

[0360] 67: Sixth Material

[0361] 70: Welding layer

[0362] F1: External force

[0363] T1: First temperature

[0364] T2: Second temperature

[0365] T3: The third temperature

[0366] T R1 : Arrival temperature

[0367] T R2 : Arrival temperature.

Claims

1. A thermal transfer recording medium, It is characterized in that Include: a substrate layer having a first side and a second side; and a fusion bonding layer, a first heat transfer layer, and a second heat transfer layer, wherein the fusion bonding layer, the first heat transfer layer, and the second heat transfer layer are sequentially stacked in direct contact with each other on the first surface of the base material layer, The fusion bonding layer has a solubility parameter (SP value) higher than each solubility parameter (SP value) of the base material layer and the first thermal transfer layer.

2. A thermal transfer recording medium, It is characterized in that Include: a substrate layer having a first side and a second side; and a fusion bonding layer, a first heat transfer layer, and a second heat transfer layer, wherein the fusion bonding layer, the first heat transfer layer, and the second heat transfer layer are sequentially stacked in direct contact with each other on the first surface of the base material layer, When heated at a low temperature that is higher than the first temperature and lower than the second temperature, the bonding force between the fusion layer and the first thermal transfer layer is higher than the bonding force between the first thermal transfer layer and the second thermal transfer layer. When heated at a high temperature exceeding the second temperature, the adhesive force between the first thermal transfer layer and the second thermal transfer layer is higher than the adhesive force between the base material layer and the first thermal transfer layer.

3. The thermal transfer recording medium according to claim 1 or 2, It is characterized in that The welding layer includes at least one selected from the group consisting of polyamide-based resins, polyester-based resins, epoxy-based resins, phenol-based resins, and polyvinyl alcohol-based resins.

4. The thermal transfer recording medium according to claim 1 or 2, It is characterized in that The first thermal transfer layer contains epoxy resin and acrylic adhesive.

5. The thermal transfer recording medium according to claim 1 or 2, It is characterized in that The second heat transfer layer includes thermoplastic resin and wax.

6. The thermal transfer recording medium according to claim 1 or 2, It is characterized in that The softening point of the fusion bonding layer is lower than the softening point of the base material layer, and the softening point of the fusion bonding layer is the same as or higher than the softening point of the first thermal transfer layer.

7. A thermal transfer recording medium, comprising a substrate layer, a welding layer containing a welding material, a first ink layer containing a first ink, and a second ink layer containing a second ink stacked in sequence, wherein at least a portion of the first ink layer and the second ink layer is thermally transferred to a printed medium, It is characterized in that In a first state where the thermal transfer recording medium is heated to a temperature not less than a first temperature and not more than a second temperature and then cooled to a temperature not more than a third temperature, when an external force is applied to the substrate layer and the second ink layer in a direction away from each other, the first ink layer and the second ink layer are broken or in the second ink layer, In the second state where the thermal transfer recording medium is heated to a temperature exceeding the second temperature and then cooled to a temperature not higher than the third temperature, when the external force is applied, the first ink layer is broken between the first ink layer and the base material layer or within the first ink layer.

8. The thermal transfer recording medium according to claim 7, It is characterized in that When the external force is applied in the first state, the breaking strength between the first ink layer and the second ink layer or within the second ink layer is the smallest in the thermal transfer recording medium. When the external force is applied in the second state, the breaking strength between the first ink layer and the base layer or within the first ink layer is the smallest in the thermal transfer recording medium.

9. The thermal transfer recording medium according to claim 7 or 8, It is characterized in that When the external force is applied in the second state, the welding layer and the base material layer are broken.

10. The thermal transfer recording medium according to claim 9, It is characterized in that When the external force is applied in the second state, the breaking strength between the fusion layer and the base layer is the smallest in the thermal transfer recording medium.

11. The thermal transfer recording medium according to claim 7 or 8, It is characterized in that The softening point of the welding layer is lower than the softening point of the base material layer, and the softening point of the welding layer is the same as the softening point of the first ink layer or higher than the softening point of the first thermal transfer layer.

12. The thermal transfer recording medium according to claim 7 or 8, It is characterized in that The welding layer has a solubility parameter (SP value) higher than each solubility parameter (SP value) of the base material layer and the first ink layer.

13. The thermal transfer recording medium according to claim 7 or 8, It is characterized in that The welding layer includes at least one selected from the group consisting of polyamide-based resins, polyester-based resins, epoxy-based resins, phenol-based resins, and polyvinyl alcohol-based resins.

14. The thermal transfer recording medium according to claim 7 or 8, It is characterized in that The thermal transfer recording medium includes an intermediate layer formed between the first ink layer and the second ink layer.

15. The thermal transfer recording medium according to claim 14, It is characterized in that When the external force is applied in the first state, the intermediate layer and the second ink layer are broken.

16. The thermal transfer recording medium according to claim 15, It is characterized in that When the external force is applied in the first state, the breaking strength between the intermediate layer and the second ink layer is minimum in the thermal transfer recording medium.

17. The thermal transfer recording medium according to claim 15 or 16, It is characterized in that The intermediate layer includes a styrene-based thermoplastic elastomer.

18. The thermal transfer recording medium according to claim 17, It is characterized in that The styrene-based thermoplastic elastomer includes at least one of styrene-butadiene-styrene block copolymer (SBS) and styrene-ethylene-butylene-styrene block copolymer (SEBS).

19. The thermal transfer recording medium according to claim 18, It is characterized in that The content of styrene in the styrene-based thermoplastic elastomer is 10% by mass to 70% by mass.

20. The thermal transfer recording medium according to claim 15 or 16, It is characterized in that The intermediate layer includes an acetate-based thermoplastic elastomer.

21. The thermal transfer recording medium according to claim 20, It is characterized in that The acetate-based thermoplastic elastomer includes ethylene-vinyl acetate copolymer (EVA).

22. The thermal transfer recording medium according to claim 14, It is characterized in that In the first state, the first ink layer is mixed with the intermediate layer.

23. The thermal transfer recording medium according to claim 14, It is characterized in that When the external force is applied in the first state, the intermediate layer is internally broken.

24. The thermal transfer recording medium according to claim 23, It is characterized in that When the external force is applied in the first state, the breaking strength of the intermediate layer is the smallest in the thermal transfer recording medium.

25. The thermal transfer recording medium according to claim 23 or 24, It is characterized in that The intermediate layer includes at least one of a polyolefin-based resin and a long-chain alkyl-based resin.

26. The thermal transfer recording medium according to claim 14, It is characterized in that The first ink layer comprises at least a first material and a second material, The intermediate layer comprises a third material, The second ink layer comprises a fourth material and a fifth material, The welding layer comprises a sixth material, The solubility parameters (SP values) of the first material, the third material, and the fifth material are smaller than the solubility parameters (SP values) of the second material, the fourth material, and the sixth material, The solubility parameters (SP values) of the second material and the fourth material are smaller than the solubility parameter (SP value) of the sixth material.

27. The thermal transfer recording medium according to claim 7 or 8, It is characterized in that The first temperature is equal to or higher than the third temperature.

28. The thermal transfer recording medium according to claim 7 or 8, It is characterized in that The first state is a state in which the base material layer of the thermal transfer recording medium is heated to a temperature not lower than the first temperature and not higher than the second temperature and then cooled to a temperature not higher than the third temperature. The second state is a state in which the base material layer of the thermal transfer recording medium is heated to a temperature exceeding the second temperature and then cooled to a temperature not higher than the third temperature.

29. A printing device, performing: A heating step of heating the thermal transfer recording medium while the thermal transfer recording medium is in contact with a medium to be printed, the thermal transfer recording medium being formed by sequentially stacking a base layer, a welding layer containing a welding material, a first ink layer containing a first ink, and a second ink layer containing a second ink; a cooling step of cooling the thermal transfer recording medium heated by the heating step; and a transfer step of applying an external force to the base layer and the second ink layer of the thermal transfer recording medium cooled in the cooling step in a direction away from each other, thereby transferring at least a portion of the first ink and the second ink to the printed medium; It is characterized in that In the heating step and the cooling step, The first portion of the thermal transfer recording medium is heated to a temperature that is higher than a first temperature and lower than a second temperature and then cooled to a third temperature or lower as a first state, and the second portion of the thermal transfer recording medium is heated to a temperature that is higher than the second temperature and then cooled to a temperature or lower than the third temperature as a second state, In the transfer process, By applying the external force, the thermal transfer recording medium is broken between the first ink layer and the second ink layer or in the second ink layer at the first portion of the thermal transfer recording medium, thereby transferring the second ink to the printed medium, By applying the external force, the thermal transfer recording medium is broken between the first ink layer and the base material layer or in the first ink layer at the second portion of the thermal transfer recording medium, thereby transferring the first ink and the second ink to the printed medium.

30. A box, It is characterized in that Built-in: The thermal transfer recording medium according to claim 1 or 7; and A printed medium to which a portion of the thermal transfer recording medium is thermally transferred.

Images