Thermal transfer recording medium and printing device

Abstract

To provide a thermal transfer recording medium that can record characters of at least two colors having good sharpness.SOLUTION: A thermal transfer recording medium 47 includes: a base material layer 48 having a front surface 53 and a rear surface 54; and a welding layer 70, a first thermal transfer layer 50, an intermediate layer 51, and a second thermal transfer layer 52 laminated in direct contact with each other in this order on the front surface 53 of the base material layer 48. The welding layer 70 has a solubility parameter (SP value) higher than those of the base material layer 48 and the first thermal transfer layer 50.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to a thermal transfer recording medium capable of recording characters of different colors, and a printing device for transferring the thermal transfer recording medium onto a print-receiving medium. [Background technology]

[0002] For example, Patent Documents 1 and 2 disclose thermal transfer recording media capable of recording characters of different colors (for example, two colors, black and red). This type of thermal transfer recording medium is set in a dedicated printing device. By adjusting the amount of energy applied to the thermal head of the printing device, characters of different colors can be transferred onto the print-receiving medium. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-094843 [Patent Document 2] Japanese Patent Application Publication No. 62-227788 [Patent Document 3] Japanese Patent Application Publication No. 63-214481 Summary of the Invention [Problem to be solved by the invention]

[0004] One embodiment of the present disclosure provides a thermal transfer recording medium capable of recording characters in at least two colors with good clarity. [Means for solving the problem]

[0005] A thermal transfer recording medium according to one embodiment of the present disclosure includes a substrate layer having a first side and a second side, and a welding layer, a first thermal transfer layer, and a second thermal transfer layer laminated in direct contact with each other in that order on the first side of the substrate layer, wherein the welding layer has a solubility parameter (SP value) higher than the SP values ​​of the substrate layer and the first thermal transfer layer. [Effects of the Invention]

[0006] The thermal transfer recording medium according to one embodiment of the present disclosure has a welding layer having a solubility parameter (SP value) higher than the solubility parameters (SP values) of the substrate layer and the first thermal transfer layer, and is therefore capable of recording characters in at least two colors with good clarity. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram schematically illustrating the structure of a printing device according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a block diagram showing the electrical configuration of the printing device. [Figure 3] FIG. 3 is a schematic diagram illustrating the heating process and the cooling process of the printing device. [Figure 4] 4A and 4B are schematic diagrams illustrating the cooling step and the transfer step of the printing device. [Figure 5] 5A and 5B are diagrams showing examples of patterns printed by the printing device. [Figure 6] FIG. 6 is a schematic cross-sectional view showing the layer structure of an ink ribbon according to an embodiment of the present disclosure. [Figure 7] FIG. 7 is a diagram showing the relationship between the elapsed time and the temperature reached by the thermal transfer recording medium in the heating step and the cooling step. [Figure 8] FIG. 8 is a diagram showing the relationship between the elapsed time in the heating step and the cooling step and the interlayer adhesive strength of the thermal transfer recording medium. [Figure 9] FIG. 9 is a diagram showing the relationship between the elapsed time in the heating step and the cooling step and the interlayer adhesive strength of the thermal transfer recording medium. [Figure 10] FIG. 10 is a diagram showing the state of peeling of the thermal transfer recording medium. [Figure 11] FIG. 11 is a diagram showing the state of peeling of the thermal transfer recording medium. [Figure 12] FIG. 12 is a diagram showing the state of peeling of the thermal transfer recording medium. [Figure 13] FIG. 13 is a diagram showing the state of peeling of the thermal transfer recording medium. [Figure 14] FIG. 14 is a diagram showing the state of peeling of the thermal transfer recording medium. [Figure 15] FIG. 15 is a diagram showing the state of peeling of the thermal transfer recording medium. [Figure 16] FIG. 16 is a diagram showing the state of peeling of the thermal transfer recording medium. [Figure 17] FIG. 17 is a diagram showing the state of peeling of the thermal transfer recording medium. [Figure 18] FIG. 18 is a diagram for comparing the solubility parameters (SP values) of the constituent materials of a thermal transfer recording medium according to an embodiment of the present disclosure. [Figure 19] FIG. 19 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 OF THE INVENTION

[0008] Next, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0009] [Overall configuration of printing device 1] FIG. 1 is a diagram schematically illustrating the structure of a printing device 1 according to an embodiment of the present disclosure.

[0010] 1, the printing device 1 is a thermal printer of the thermal transfer type that thermally transfers ink from an ink ribbon 3 as characters onto a printer tape 2, which is an example of a print medium. The printer tape 2 may include, for example, a strip-shaped film tape including a base material onto which ink is directly transferred, or a paper label tape in which many paper labels are arranged on a strip-shaped base film.

[0011] The characters recorded on the printer 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 of different colors (for example, two colors, black and red) on the printer tape 2.

[0012] The printing device 1 mainly includes a housing 4, a tape cassette 5 housed inside the housing 4, a thermal head 6, a platen roller 7, and a control board 8.

[0013] The housing 4 may be a box-shaped member made of, for example, a plastic case. An outlet 9 is formed on the outer wall of the housing 4 for removing the printer tape 2 after printing. A cutter (not shown) may be provided near the outlet 9. By cutting with the cutter, the printer tape 2 can be separated into labels of a size appropriate for each unit of use and removed.

[0014] The tape cassette 5 may be a cartridge that is detachable from the housing 4. The tape cassette 5 may house, in order from upstream to downstream in the tape feed direction D1 (the direction from right to left in FIG. 1 ), a printer tape roll 10 (which may alternatively be a label tape roll), a supply roller 11, an ink ribbon roll 12, an ink ribbon peeling member 13, and an ink ribbon take-up roll 14. In this embodiment, the printer tape roll 10 and the ink ribbon roll 12 are of a type that are used while housed in the tape cassette 5, but they may also be of a type that is used by being directly attached to the printing device 1, for example.

[0015] Printer tape roll 10 is made by winding printer tape 2 into a cylindrical shape and is rotatably held in, for example, tape cassette 5. Tape drive shaft 16 provided in housing 4 is inserted into supply roller 11. Rotational force R1 generated by driving tape drive shaft 16 is transmitted to supply roller 11, causing supply roller 11 to rotate.

[0016] The ink ribbon roll 12 is made by winding the ink ribbon 3 into a cylindrical shape, and is rotatably held in, for example, a tape cassette 5. A ribbon drive shaft 18 provided in the housing 4 is inserted into the ink ribbon take-up roll 14. A rotational force R2 generated by driving the ribbon drive shaft 18 is transmitted to the ink ribbon take-up roll 14, causing the ink ribbon take-up roll 14 to rotate.

[0017] The ink ribbon separating member 13 may be a guide member that changes the feed direction D2 of the ink ribbon 3. The ink ribbon separating member 13 may have a shape that can come into contact with the ink ribbon 3 while it is being transported, such as a roller or blade shape. A portion of the ink ribbon 3 is thermocompressed to the printer tape 2 by the thermal head 6, and is transported together with the printer tape 2 toward the outlet 9. The ink ribbon separating member 13 comes into contact with the ink ribbon 3 while it is being transported, and changes the feed direction D2 of the ink ribbon 3 at a steep angle relative to the feed direction D1 of the printer tape 2. This causes the printer tape 2 and the ink ribbon 3 to be separated, and the ink ribbon 3 is separated from the printer tape 2.

[0018] The thermal head 6 is disposed between the printer tape roll 10, the ink ribbon roll 12, and the ink ribbon peeling member 13 in the feed direction D1 of the printer tape 2. The thermal head 6 includes a substrate 19 and a heating element 20 (e.g., a heating resistor) formed on the substrate 19. Joule heat generated by energizing the heating element 20 is used for thermally transferring the ink on the ink ribbon 3.

[0019] For example, a platen drive shaft 21 provided in the housing 4 is inserted into the platen roller 7. A rotational force R3 generated by driving the platen drive shaft 21 is transmitted to the platen roller 7, causing the platen roller 7 to rotate. The control board 8 is an electronic device that performs electrical control of the printing device 1, and is installed inside the housing 4.

[0020] [Electrical configuration of printing device 1] FIG. 2 is a block diagram showing the electrical configuration of the printing device 1. As shown in FIG.

[0021] 2, a control circuit 22 is provided on the control board 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), which are electrically connected via, for example, a data bus (not shown).

[0022] The ROM 24 stores various programs for driving the printing device 1 (for example, control programs for executing the steps shown in FIG. 3 and FIGS. 4A and 4B). The CPU 23 executes signal processing in accordance with the programs stored in the ROM 24 while utilizing the temporary storage function of the RAM 26, and controls the printing device 1 as a whole. The memory 25 may be configured, for example, as a part of the storage area of ​​the ROM 24. The memory 25 may also store in advance a table for displaying the remaining amount (amount consumed) of the ink ribbon 3 on a display unit (not shown) of the housing 4.

[0023] A first drive circuit 28 and a second drive circuit 29 are electrically connected to the input / output I / F 27. The first drive circuit 28 controls the energization of the heating elements 20 of the thermal head 6. The second drive circuit 29 controls the drive to output drive pulses to a drive motor 30 that drives the supply roller 11, the ink ribbon take-up roll 14, and the platen roller 7 to rotate.

[0024] [Printing process flow by printing device 1] FIG. 3 is a schematic diagram illustrating the heating process and cooling process of the printing device 1. FIGS. 4A and 4B are schematic diagrams illustrating the cooling process and transfer process of the printing device 1. FIG. 4B is an enlarged view of a main part of the transfer pattern when viewed from the direction of arrow 4B in FIG. 4A. FIGS. 5A and 5B are diagrams showing an example of a print pattern 44 printed by the printing device 1. The printing process by the printing device 1 will be specifically described with reference to FIGS. 1 and 3 to 5A and 5B.

[0025] To print characters on the printer tape 2, the printer tape 2 is fed from the printer tape roll 10 by the rotational drive of the supply roller 11, and the ink ribbon 3 is fed from the ink ribbon roll 12 by the rotational drive of the ink ribbon take-up roll 14. As a result, the printer tape 2 and the ink ribbon 3 are transported downstream while overlapping each other, as shown in Figures 1 and 3. The surface of the printer tape 2 facing the ink ribbon 3 is the printing surface 31 (front surface), and the opposite surface is the back surface 32. The surface of the ink ribbon 3 facing the printer tape 2 is the adhesive surface 33 (front surface), and the opposite surface is the back surface 34.

[0026] 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 laminated in this order on a front surface 38 as an example of a first surface of the base layer 35. The surface of the base layer 35 opposite the front surface 38 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. 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.

[0027] The ink ribbon 3 is transported toward the thermal head 6 with the second ink layer 37 and the printer tape 2 in contact with each other. In the thermal head 6, a heating process is carried out as shown in Figure 3. Specifically, when the heating elements 20 are energized and generate heat, they are pressed against the ink ribbon 3, and this heat is transferred to the first ink layer 36 and the second ink layer 37 via the base layer 35. The laminate of the ink ribbon 3 and the printer tape 2 is sandwiched between the thermal head 6 and the platen roller 7, and is transported downstream while being heated by the thermal head 6.

[0028] The heating element 20 may be controlled to the same temperature throughout, or may be controlled to partially different temperatures. For example, as shown in FIG. 3 , a first portion 40 of the heating element 20 may be controlled to a first heating temperature, and a second portion 41 of the heating element 20 may be controlled to a second heating temperature different from the first heating temperature. As a result, the ink ribbon 3 may include a first portion 42 heated to the first heating temperature and a second portion 43 heated to the second heating temperature. In the first portion 42 and the second portion 43 of the ink ribbon 3, at least part or all of the first ink layer 36 and the second ink layer 37 melt or soften and adhere to the printer tape 2.

[0029] 3 and 4A and 4B, a cooling process is carried out in the section between the thermal head 6 and the ink ribbon peeling member 13. Specifically, the ink ribbon 3, which has been thermocompressed to the printer tape 2 in the heating process, is naturally cooled in the section from the thermal head 6 to the ink ribbon peeling member 13, and its temperature drops toward the ambient temperature in which the printing device 1 is used.

[0030] 4A and 4B, the ink ribbon peeling member 13 selectively changes only the feed direction D2 of the ink ribbon 3, thereby applying an external force F1 to the base layer 35 and the second ink layer 37 in directions that move them away from each other. This separates the printer tape 2 and the ink ribbon 3, and the ink ribbon 3 is taken up onto the ink ribbon take-up roll 14. At this time, the first portion 42 and the second portion 43 of the ink ribbon 3, which have been heated by the thermal head 6, selectively remain on the printer tape 2, thereby performing the transfer process. For example, in the first portion 42, peeling may occur between the base layer 35 and the laminate including the first ink layer 36 and the second ink layer 37, resulting in the transfer of the laminate. Meanwhile, in the second portion 43, peeling may occur between the first ink layer 36 and the second ink layer 37, resulting in the selective transfer of the second ink layer 37.

[0031] As a result, printed patterns 44 of different colors (for example, two colors, black and red) are formed on the printer tape 2. The printed pattern 44 may have different colors for each individual character, as shown in FIG. 5A, for example. In FIG. 5A, when viewed from the printed surface 31 side of the printer tape 2, a red pattern 45 based on the second ink layer 37 may be visible on the outermost surfaces of the alphabet letters "A" and "C," and a black pattern 46 based on the first ink layer 36 may be visible on the outermost surface of "B." On the other hand, as shown in FIG. 5B, the printed pattern 44 may have both a red pattern 45 and a black pattern 46 visible for each part of each character.

[0032] After the ink ribbon 3 is transferred, the printer tape 2 on which the characters are recorded is removed from the printer 1 through the removal port 9.

[0033] [Example of issues with two-color printing] In a thermal transfer thermal printer (printing device 1), the ink ribbon 3 is heated by the thermal head 6 according to the pattern of recording information, and then the ink ribbon 3 is peeled off from the printer tape 2. As a result, the ink layers 36, 37 are selectively melted or softened according to the heating pattern, peeled off from the base layer 35, and transferred to the printing surface 31 of the printer tape 2, recording characters on the printing surface 31. Two-color thermal transfer printing such as that described above is also disclosed in the aforementioned Patent Documents 1 and 2, but has the following problems.

[0034] For example, Patent Document 1 discloses a thermal transfer sheet that includes 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 laminated on the substrate for two-color recording. Both thermal transfer ink layers are formed from thermoplastic resin, wax, etc.

[0035] In Patent Document 1, for example, when relatively low energy is applied to the thermal head to perform thermal transfer at a relatively low temperature, the first thermal transfer ink layer softens, reducing its adhesion to the substrate, and the second thermal transfer ink layer softens, increasing its adhesion to the surface of the transfer recipient. However, both thermal transfer ink layers maintain their adhesion by softening, so that the entire thermal transfer ink layer, i.e., the first thermal transfer ink layer and the second thermal transfer ink layer, are thermally transferred integrally to the surface of the transfer recipient. As a result, the characters recorded on the surface of the transfer recipient will be the color of the first thermal transfer ink layer, which is the outermost layer after transfer, such as black.

[0036] On the other hand, if a relatively high energy is applied to the thermal head and thermal transfer is performed at a higher temperature, the first thermal transfer ink layer further softens, conversely increasing its adhesion to the substrate, while the second thermal transfer ink layer softens and develops adhesion to the surface of the transfer recipient. During this thermal transfer, the first thermal transfer ink layer remains on the substrate, a process known as reverse transfer. As a result, only the second thermal transfer ink layer is selectively thermally transferred to the surface of the transfer recipient. Therefore, the characters recorded on the surface of the transfer recipient will be the color of the second thermal transfer ink layer, for example, red.

[0037] However, between the range of transfer temperatures (≒ the amount of energy applied to the thermal head, same below) when both thermal transfer ink layers are thermally transferred together (hereinafter sometimes abbreviated as the "low temperature transfer range") and the range of transfer temperatures when only the second thermal transfer ink layer is thermally transferred (hereinafter sometimes abbreviated as the "high temperature transfer range"), there may be a range of transfer temperatures (hereinafter sometimes abbreviated as the "cloudy transfer range") where part of the first thermal transfer ink layer is transferred together with the second thermal transfer ink layer, causing the color of the characters to become cloudy.

[0038] Furthermore, thermal transfer sheets in which both thermal transfer ink layers are directly laminated tend to have a wide cloudy transfer range and narrow low-temperature and high-temperature transfer ranges. Furthermore, continuous thermal transfer printing tends to accumulate heat in the thermal head, gradually increasing its temperature. This makes it particularly difficult to maintain the thermal head temperature within the low-temperature transfer range, making it easy for the color of the characters to become cloudy during low-temperature transfer.

[0039] The thermal transfer sheet of Patent Document 1 may further include a release layer formed between the first thermal transfer ink layer and the second thermal transfer ink layer. The release layer is made of a colorless, transparent, low-melting-viscosity, highly fluid wax or the like. The release layer melts or softens during thermal transfer, promoting separation of the two thermal transfer ink layers. The high-temperature transfer range can be expanded toward the lower temperature side, narrowing the cloudy transfer range. However, this tends to narrow the low-temperature transfer range in which both thermal transfer ink layers can be transferred together while suppressing peeling of the release layer. In addition, wax has a low melting viscosity and is therefore prone to affecting the surrounding area. In particular, when recording fine images such as barcodes, excess peeling can occur, reducing the clarity of the recording.

[0040] Patent Document 2 discloses an ink ribbon including a base and a first ink layer and a second ink layer laminated directly on the base. In Patent Document 2, the ink ribbon is first heated in a low-temperature transfer range, and both ink layers are thermally transferred integrally to the surface of the base. If only the second ink layer is to remain, the ink ribbon may be heated again when peeled off, resulting in reverse transfer of the first ink layer to the base. However, the thermal transfer printing of Patent Document 2 requires a printer equipped with a special thermal head capable of reheating after thermal transfer, which limits its versatility.

[0041] The inventors of the present application have discovered several problems in consideration of the thermal transfer methods of Patent Documents 1 and 2. At least one of the problems (the first problem) is to provide a thermal transfer recording medium (ink ribbon) capable of simultaneously recording characters in at least two colors with good clarity.

[0042] Another one of the above multiple objectives (the second objective) is to provide a thermal transfer recording medium (ink ribbon) that can clearly separate two colors without causing color mixing even when thermal transfer recording is performed continuously using a general-purpose thermal transfer printer that is compatible with two-color recording.

[0043] Another one of the above multiple objectives (the third objective) is to provide a thermal transfer recording medium (ink ribbon) that can be used with a general-purpose thermal transfer printer that is compatible with two-color recording, and that can clearly separate the two colors without causing color mixing even when thermal transfer recording is performed continuously, and that can record characters with excellent clarity without causing residual peeling.

[0044] [Introduction of welding layer 70] In order to solve the above-mentioned problems, the inventors of the present invention have investigated and implemented the introduction of a welding layer into a thermal transfer recording medium (ink ribbon), which will be described in detail below.

[0045] Fig. 6 is a schematic cross-sectional view showing the layer structure of a thermal transfer recording medium 47 according to an embodiment of the present disclosure, in which the thermal transfer recording medium 47 is adhered to a printer tape 2 as an example of a print-receiving medium.

[0046] The thermal transfer recording medium 47 may be used as the ink ribbon 3 in the printing device 1 and printing process shown in FIGS. 1 to 4A and 4B. The thermal transfer recording medium 47 includes a substrate layer 48, a backing layer 49, a welding layer 70, a first thermal transfer layer 50, an intermediate layer 51, and a second thermal transfer layer 52. The welding layer 70, the first thermal transfer layer 50, the intermediate layer 51, and the second thermal transfer layer 52 are laminated in this order on a front surface 53, which is an example of a first surface, of the substrate layer 48. The surface of the substrate layer 48 opposite the front surface 53 may be a back surface 54. The backing layer 49 is laminated on the back surface 54 of the substrate 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.

[0047] The thermal transfer recording medium 47 of the present disclosure is characterized in that it includes a substrate layer 48 and a welding layer 70, a first thermal transfer layer 50, an intermediate layer 51, and a second thermal transfer layer 52, which are laminated in this order on a surface 53 of the substrate layer 48 and in direct contact with each other. The intermediate layer 51 contains a thermoplastic elastomer as a binder. The intermediate layer 51 may be omitted.

[0048] The specific compositions and physical properties of the substrate layer 48, backing layer 49, welding layer 70, first thermal transfer layer 50, intermediate layer 51, and second thermal transfer layer 52 contained in the thermal transfer recording medium 47 will be described in detail below.

[0049] (1) Base material layer 48 Examples of the substrate layer 48 include resin films such as polysulfone, polystyrene, polyamide, polyimide, polycarbonate, polypropylene, polyester, and triacetate; thin paper such as condenser paper and glassine paper; and cellophane. Among these, polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate are preferred from the standpoints of mechanical strength, dimensional stability, heat treatment resistance, and cost. The thickness of the substrate layer 48 can be set arbitrarily depending on, for example, the specifications of the thermal transfer printer. For example, the thickness of the substrate layer 48 is 1 μm or more, preferably 2 μm or more. For example, the thickness of the substrate layer 48 is 10 μm or less, preferably 8 μm or less. For example, the thickness of the substrate layer 48 is 1 μm or more and 10 μm or less, preferably 2 μm or more and 8 μm or less.

[0050] (2) Back layer 49 The back surface layer 49 improves the heat resistance, slipperiness, abrasion resistance, etc. of the back surface 54 of the base material layer 48 that comes into contact with the thermal head 6. Examples of materials for the back surface layer 49 include silicone resin, fluororesin, silicone-fluorine copolymer resin, nitrocellulose resin, silicone-modified urethane resin, and silicone-modified acrylic resin. The back surface layer 49 may contain a lubricant as needed.

[0051] The back surface layer 49 can be formed, for example, by applying a coating material in which the above-mentioned resin or the like is dissolved or dispersed in an arbitrary solvent to the back surface 54 of the base material layer 48 and then drying the coating material. The thickness of the back surface layer 49 can be set as desired depending on, for example, the specifications of the thermal transfer printer. The thickness of the back surface layer 49 can be adjusted by the amount of the back surface layer 49 applied.

[0052] For example, the coating amount of the back layer 49 is 0.05 g / m 2 in terms of the amount of solid content per unit area. 2 or more, preferably 0.1 g / m 2 For example, the coating amount of the back layer 49 is 0.5 g / m2 in terms of the amount of solid content per unit area. 2 or less, preferably 0.4 g / m 2 For example, the coating amount of the back layer 49 is 0.05 g / m2 in terms of the amount of solid content per unit area. 2 More than 0.5g / m 2 or less, preferably 0.1 g / m 2 More than 0.4g / m 2 The specific thickness of the back surface layer 49 is, for example, 0.05 μm or more, and preferably 0.1 μm or more. The thickness of the back surface layer 49 is, for example, 0.5 μm or less, and preferably 0.4 μm or less. The thickness of the back surface layer 49 may be, for example, 0.05 μm or more and 0.5 μm or less, and preferably 0.1 μm or more and 0.4 μm or less.

[0053] (3) Welding layer 70 The welding layer 70 contains at least one resin selected from the group consisting of polyamide resin, polyester resin, epoxy resin, phenol resin, and polyvinyl alcohol resin. The welding layer 70 is preferably formed using a polyamide resin in order to improve the affinity and adhesion to the base layer 48 and the first thermal transfer layer 50 during low-temperature heating.

[0054] Examples of polyamide resins include polyamides obtained by polycondensation of lactams with three or more ring members, polymerizable aminocarboxylic acids, dibasic acids and diamines or their salts, or mixtures thereof. These polyamide resins can be used alone or in combination of two or more.

[0055] Specific examples of commercially available polyamide resins include the TOMAID (registered trademark) series manufactured by T&K TOKA Corporation, such as 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), and 1320 (softening point: 100±5°C, melt viscosity: 11000 to 20000 mPa·s / 200°C)], 1340 [softening point: 140±5°C, melt viscosity: 8000 to 16000 mPa·s / 200°C], TXC-243A [softening point: 105±5°C, melt viscosity: 5000 to 10000 mPa·s / 200°C], TXC-245A [softening point: 90±5°C, melt viscosity: 1000 to 2000 mPa·s / 200°C], etc.

[0056] In this application, when comparing temperatures related to thermal deformation of multiple substances, the softening point is used as the comparison temperature for substances that have a softening point, such as polyamide resins. For substances that have a melting point (such as wax, which will be described later), the melting point is used as the comparison temperature. For substances that do not have either a melting point or a softening point but have a glass transition temperature (such as polyester resins, which will be described later), the glass transition temperature is used as the comparison temperature.

[0057] Specific examples of commercially available polyester resins include UE-3320, UE-9820, UE-3350, and UE-3380 from the Elitel (registered trademark) series manufactured by Unitika 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), and GK-680 (glass transition temperature: 10°C) from the Vylon (registered trademark) series manufactured by Toyobo Co., Ltd.

[0058] Specific examples of commercially available epoxy resins include the basic solid types of epoxy resins in the JER (registered trademark) series manufactured by Mitsubishi Chemical Corporation, such as 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], and 1004AF [softening point ( Ring and ball method): 97℃, number average molecular weight Mn: approx. 1650〕, 1007 [Softening point (ring and ball method): 128℃, number average molecular weight Mn: approx. 2900〕, 10 09 [Softening point (ring and ball method): 144℃, 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], 100 4FS [Softening point (ring and ball method): 100℃], 1006FS [Softening point (ring and ball method): 112℃], 1007FS [Softening point (ring and ball method): 124℃].

[0059] Specific examples of commercially available 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), and TD-2090 (softening point: 117 to 123°C) from 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) and BRG- 556 [softening point: 77 to 83°C, melt viscosity: 0.1 to 0.3 Pa·s / 150°C], BRG-557 [softening point: 82 to 88°C, melt viscosity: 0.2 to 0.4 Pa·s / 150°C], BRG-558 [softening point: 93 to 98°C, melt viscosity: 0.8 to 1.2 Pa·s / 150°C], CRG-951 [softening point: 93 to 99°C, melt viscosity: 0.2 to 0.8 Pa·s / 150°C], and TAM-005 [softening point: 80 to 88°C, melt viscosity: 0.3 to 0.5 Pa·s / 150°C].

[0060] The polyvinyl alcohol resin is preferably, for example, a partially saponified polyvinyl alcohol resin having a degree of saponification of 90 or less. The degree of polymerization of the polyvinyl alcohol resin is, for example, 2000 or less, and preferably about 500. Specific commercially available polyvinyl alcohol resins include, for example, B-05 [saponification degree: 86.5 to 89.5 mol%, degree of polymerization: about 500, viscosity (4%, 20°C): 5.0 to 6.0 mPa·s], B-17 [saponification degree: 87.0 to 89.0 mol%, degree of polymerization: about 1600, viscosity (4%, 20°C): 21 to 25 mPa·s], and B-20 [saponification degree: 87.0 to 89.0 mol%, degree of polymerization: about 2000] from the Denka Poval (registered trademark) series manufactured by Denka Co., Ltd. and from the Kuraray Poval (registered trademark) series manufactured by Kuraray Co., Ltd., examples include 48-80 [degree of saponification: 78.5 to 80.5 mol%, viscosity (4%, 20°C): 45.0 to 51.0 mPa·s], 3-88 [degree of saponification: 87.0 to 89.0 mol%, viscosity (4%, 20°C): 3.2 to 3.6 mPa·s], and 5-88 [degree of saponification: 86.5 to 89.0 mol%, viscosity (4%, 20°C): 4.6 to 5.4 mPa·s].

[0061] The softening point of the polyamide resin used in the welding layer 70 is, for example, 90° C. or higher, preferably 110° C. or higher, and more preferably 125° C. or higher. If the softening point is within this range, the resin hardly softens at the relatively low temperatures that occur during low-temperature transfer, and high adhesive strength can be maintained between the base layer 48 and the first thermal transfer layer 50.

[0062] The welding layer 70 can be formed, for example, by applying a coating material in which the forming material for the welding layer 70 is dissolved or dispersed in any solvent onto the surface 53 of the base layer 48 and then drying it.

[0063] The thickness of the welding layer 70 can be set arbitrarily depending on, for example, the specifications of the thermal transfer printer. The thickness of the welding layer 70 can be adjusted by the amount of the welding layer 70 applied. For example, the amount of the welding layer 70 applied is 0.1 g / m2 in terms of the amount of solid content per unit area.2 or more, and preferably 0.2 g / m 2 For example, the coating amount of the welding layer 70 is 1.5 g / m2 in terms of the amount of solid content per unit area. 2 and preferably 1.0 g / m 2 For example, the coating amount of the welding layer 70 is 0.1 g / m2 in terms of the amount of solid content per unit area. 2 More than 1.5g / m 2 or less, preferably 0.2 g / m 2 More than 1.0g / m 2 The following is the result.

[0064] The specific thickness of the welding layer 70 (before printing) may be, for example, 0.05 μm to 1.5 μm, and preferably 0.2 μm to 1.0 μm. The thickness of the welding layer 70 can be confirmed based on, for example, a scanning electron microscope (SEM) image or a transmission electron microscope (TEM) image of the thermal transfer recording medium 47.

[0065] (4) First thermal transfer layer 50 The first thermal transfer layer 50 can be formed, for example, from any thermoplastic resin. Considering the need to improve the affinity and adhesive strength for the welding layer 70 and intermediate layer 51, it is preferable to form the first thermal transfer layer 50 using an epoxy resin as the thermoplastic resin. Epoxy resins have excellent affinity and adhesive strength for the thermoplastic elastomer that forms the base layer 48, which is made of a polyester film such as PET, and the intermediate layer 51. The first thermal transfer layer 50 can be formed using an epoxy resin that does not contain (excludes) a curing agent as the thermoplastic resin.

[0066] Examples of epoxy resins include bisphenol A epoxy resins, bisphenol F epoxy resins, phenol novolac epoxy resins, cresol novolac epoxy resins, alicyclic epoxy resins, hydrogenated bisphenol A epoxy resins, hydrogenated bisphenol AD ​​epoxy resins, aliphatic epoxy resins such as propylene glycol glycoxyl ether and 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, and brominated epoxy resins. Specific examples of epoxy resins include, but are not limited to, the following epoxy resins. These epoxy resins can be used alone or in combination of two or more.

[0067] Among the JER (registered trademark) series epoxy resins manufactured by Mitsubishi Chemical Corporation, the basic solid types are 1001 [softening point (ring and ball method): 64°C, number average molecular weight Mn: approximately 900], 1002 [softening point (ring and ball method): 78°C, number average molecular weight Mn: approximately 1200], 1003 [softening point (ring and ball method): 78°C, number average molecular weight Mn: approximately 1200], Softening point (ring and ball method): 89℃, number average molecular weight Mn: approx. 1300], 1055 [softening point (ring and ball method): 93℃, number average molecular weight Mn: approx. 160 0], 1004 [Softening point (ring and ball method): 97℃, number average molecular weight Mn: about 1650], 1004AF [Softening point (ring and ball method): 97℃, number average Molecular weight Mn: about 1650], 1007 [softening point (ring and ball method): 128℃, number average molecular weight Mn: about 2900], 1009 [softening point (ring and ball method) method): 144℃, number average molecular weight Mn: approximately 3800], 1010 [number average molecular weight Mn: approximately 5500], 1003F [softening point (ring and ball method): 96℃], 1004F [Softening point (ring and ball method): 103℃], 1005F, 1009F [Softening point (ring and ball method): 144℃], 1004FS [Softening point (ring and ball method): 100℃], 1006FS [Softening point (ring and ball method): 112℃], 1007FS [Softening point (ring and ball method): 124℃].

[0068] The softening point of the epoxy resin used in 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.

[0069] The first thermal transfer layer 50 may contain an adhesive in addition to the epoxy resin. The inclusion of an adhesive can further improve the affinity and adhesion to the welding layer 70 and the intermediate layer 51. Examples of adhesives include rubber-based adhesives, acrylic-based adhesives, silicone-based adhesives, vinyl alkyl ether-based adhesives, polyvinyl alcohol-based adhesives, polyvinylpyrrolidone-based adhesives, polyacrylamide-based adhesives, and cellulose-based adhesives.

[0070] Considering the affinity and compatibility with the epoxy resin, and the affinity and adhesion to the welding layer 70 and intermediate layer 51, an acrylic adhesive is preferred as the adhesive. Specific examples of the acrylic adhesive include, but are not limited to, the following acrylic adhesives. These acrylic adhesives can be used alone or in combination of two or more.

[0071] Among the Olivine (registered trademark) BPS (solvent-based) series manufactured by Toyochem Co., Ltd., 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: 35% by mass), BPS5215K (non-volatile content: 39% by mass), BPS5227-1 (non-volatile content: 41.5% by mass), BPS5296 (non-volatile content: 37% by mass), BPS5330 (non-volatile content: 40% by mass), BPS5375 (non-volatile content: 45% by mass), BPS5448 (non-volatile content: 40% by mass), BPS5513 (non-volatile content: 44.5% by mass), BPS55 65K (non-volatile content: 45% by mass), BPS5669K (non-volatile content: 46% by mass), BPS5762K (non-volatile content: 45.5% by mass), BPS5896 (non-volatile content: 37% by mass), BPS5978 (non-volatile content: 35% by mass), BPS6074HTF (non-volatile content: 52% by mass), BPS6080TFK (non-volatile content: 45% by mass), BPS6130TF (non-volatile content: 52% by mass), BPS6153K (non-volatile content: 25% by mass), BPS6163 (non-volatile content: 37% by mass), BPS6231 (non-volatile content: 56% by mass), BPS6421 (non-volatile content: 47% by mass), BPS6430 (non-volatile content: 33% by mass), BPS6574 (non-volatile content: 57% by mass), BPS8170 (non-volatile content: 36.5% by mass), BPS HS-1 (non-volatile content: 40% by mass).

[0072] Among the solvent-based adhesives (removable) manufactured by Lion Specialty Chemicals Co., Ltd., the following are used: AS-325 (solid content: 45% by mass), AS-375 (solid content: 45% by mass), AS-409 (solid content: 45% by mass), AS-417 (solid content: 45% by mass), AS-425 (solid content: 45% by mass), AS-455 (solid content: 45% by mass), AS-665 (solid content: 40% by mass), AS-1107 (solid content: 43% by mass), and AS-4005 (solid content: 45% by mass).

[0073] The acrylic adhesive used in the first thermal transfer layer 50 may be used in combination with a tackifier. This is because, for example, it is possible to improve the sharpness of the first thermal transfer layer 50, suppress excess peeling, and improve the clarity of the recorded characters. Examples of tackifiers include ester gum, terpene phenol resin, and rosin ester. Specific examples of tackifiers are not particularly limited, but include the following various tackifiers. These tackifiers can be used alone or in combination of two or more types.

[0074] Among the terpene phenol resins in the YS Polyster series manufactured by Yasuhara Chemical Co., Ltd., U130 (softening point: 130±5°C), U115 (softening point: 115±5°C), T160 (softening point: 160±5°C), T145 (softening point: 145±5°C), T130 (softening point: 130±5°C), 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℃), TH130 (softening point: 130±5℃).

[0075] Among the ester gums manufactured by Arakawa Chemical Co., Ltd., AA-G [softening point (ring and ball method): 82~88℃], AA-L [softening point (ring and ball method): 82~88℃], AA-V [softening point (ring and ball method): 82~95℃] , 105 [Softening point (ring and ball method): 100~110℃], AT [Viscosity: 20000~40000mPa·s], H [Softening point (ring and ball method): 68~75℃], HP [Softening point (ring and ball method): 80℃ or higher].

[0076] Among the rosin esters in the Pencel (registered trademark) series manufactured by Arakawa Chemical Industries, Ltd., GA-100 [softening point (Ring and Ball method): 100 to 110°C], AZ [softening point (Ring and Ball method): 95 ~105℃], C [Softening point (ring and ball method): 117~127℃], D-125 [Softening point (ring and ball method): 120~130℃], D-135 [Softening Point (ring and ball method): 130~140℃], D-160 [softening point (ring and ball method): 150~165℃], KK [softening point (ring and ball method): 165℃ or higher].

[0077] The softening point of the tackifier used in the first thermal transfer layer 50 is, for example, 60°C or higher, and preferably 120°C or lower.

[0078] The first thermal transfer layer 50 may contain any colorant. As the colorant, one or more of various colorants can be used depending on the color of the first thermal transfer layer 50. The colorant may be, for example, a pigment. In consideration of improving the weather resistance of the letters, a pigment is preferred as the colorant used in the first thermal transfer layer 50. For example, carbon black is preferred as a pigment for coloring the first thermal transfer layer 50 black. Specific examples of carbon black are not particularly limited, but include, for example, the following various carbon blacks. These carbon blacks can be used alone or in combination of two or more types.

[0079] Mitsubishi Chemical Corporation MA77 powder (LFF, DBP absorption capacity: 68 cm 3 / 100g], MA7 powder [LFF, DBP absorption: 66cm 3 / 100g], MA7 granules [LFF, DBP absorption: 65cm 3 / 100g], MA8 powder [LFF, DBP absorption capacity: 57cm 3 / 100g], MA8 granules [LFF, DBP absorption: 51cm 3 / 100g], MA11 powder [LFF, DBP absorption: 64cm 3 / 100g], MA100 powder [LFF, DBP absorption capacity: 100cm 3 / 100g], MA100 granules [LFF, DBP absorption: 95cm 3 / 100g], MA100R powder [LFF, DBP absorption capacity: 100cm 3 / 100g], MA100R granules [LFF, DBP absorption: 95cm 3 / 100g], MA100S powder [LFF, DBP absorption capacity: 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].

[0080] Mitsubishi Chemical Corporation #3030B (furnace method, DBP absorption: 130 cm 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).

[0081] Tokai Carbon Co., Ltd.'s Toka Black (registered trademark) series, #5500 (furnace method, DBP absorption: 155 cm 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).

[0082] Orion Engineered Carbons' PRINTEX (registered trademark) series L (furnace method, DBP absorption: 120 cm 3 / 100g), L6 (furnace method, DBP absorption: 126cm 3 / 100g).

[0083] Birla Carbon's CONDUCTEX (registered trademark) series, 975 (furnace method, 170 cm 3 / 100g), SC (furnace method, 115cm 3 / 100g).

[0084] Among the VULCAN (registered trademark) series manufactured by CABOT, XC72 (furnace method, DBP absorption: 174 cm 3 / 100g), 9A32 (furnace method, DBP absorption: 114cm 3 / 100g), and 3700 of the company's BLACK PEARLS series (furnace method, DBP absorption: 111cm 3 / 100g).

[0085] Among the Denka Black (registered trademark) series manufactured by Denka Co., Ltd., Denka Black granules (acetylene method, DBP absorption: 160 cm 3 / 100g), FX-35 (acetylene method, DBP absorption: 220cm 3 / 100g), HS-100 (acetylene method, DBP absorption: 140cm 3 / 100g).

[0086] Among the KETJENBLACK (registered trademark) series manufactured by Lion Specialty Chemicals Co., Ltd., EC300J (gasification method, DBP absorption capacity: 360 cm 3 / 100g), EC600DJ (gasification method, DBP absorption capacity: 495cm 3 / 100g).

[0087] 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, and 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, and 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, and preferably 40 parts by mass or more and 100 parts by mass or less.

[0088] The ratio of the tackifier to 100 parts by mass of the epoxy resin is, for example, 3 parts by mass or more, and 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, and 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, and preferably 5 parts by mass or more and 100 parts by mass or less.

[0089] 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.

[0090] Furthermore, for components contained in the first thermal transfer layer 50 that are supplied in liquid form dissolved or dispersed in an arbitrary solvent, the amount of active ingredient can be adjusted so that the proportion of the active ingredient falls within the above range (the same applies below).

[0091] The first thermal transfer layer 50 can be formed, for example, by applying a coating material in which the above components are dissolved or dispersed in a solvent directly onto the welding layer 70 and then drying the coating material. In this disclosure, as shown in Figures 5A and 5B, the characters to be recorded on the printer tape 2 are color-coded. For this color coding, considering adjustment of the adhesion between the first thermal transfer layer 50 and the welding layer 70 and other layers, it is preferable to form the first thermal transfer layer 50 directly on the welding layer 70.

[0092] The thickness of the first thermal transfer layer 50 can be set arbitrarily depending on, 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.

[0093] For example, the coating amount of the first thermal transfer layer 50 is 0.1 g / m 2 in terms of the amount of solids per unit area.2 or more, preferably 0.5 g / m 2 For example, the coating amount of the first thermal transfer layer 50 is 3.0 g / m2 in terms of the amount of solid content per unit area. 2 and preferably 2.5 g / m 2 For example, the coating amount of the first thermal transfer layer 50 is 0.1 g / m2 in terms of the amount of solids per unit area. 2 More than 3.0g / m 2 or less, preferably 0.5 g / m 2 More than 2.5g / m 2 The following is the result.

[0094] The specific thickness of the first thermal transfer layer 50 (before printing) is, for example, 0.05 μm or more, and preferably 0.5 μm or more. The thickness of the first thermal transfer layer 50 is, for example, 3.0 μm or less, and preferably 2.5 μm or less. The thickness of the first thermal transfer layer 50 may be, for example, 0.05 μm or more and 3.0 μm or less, and 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 scanning electron microscope (SEM) image or a transmission electron microscope (TEM) image of the thermal transfer recording medium 47.

[0095] (5) Middle class 51 The intermediate layer 51 contains a thermoplastic elastomer. In particular, the intermediate layer 51 is preferably formed solely from 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.

[0096] Examples of styrene-based thermoplastic elastomers include styrene-butadiene-styrene block copolymer (SBS), styrene-ethylene-butene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-ethylene / ethylene-propylene-styrene block copolymer (SEEPS), styrene-isoprene-styrene block copolymer (SIS), etc. Examples of acetate-based thermoplastic elastomers include ethylene-vinyl acetate copolymer (EVA).

[0097] The styrene content of the thermoplastic elastomer contained in the intermediate layer 51 is, for example, 10% by mass or more and 70% by mass or less, and preferably 15% by mass or more and 50% by mass or less. If the styrene content is too high, the rubber-like elasticity of the intermediate layer 51 decreases, and during low-temperature transfer, the adhesive strength to the first thermal transfer layer 50 and the second thermal transfer layer 52 may not be maintained, or the color of the characters may become cloudy. If the styrene content is too low, the rubber-like elasticity of the intermediate layer 51 becomes too high, and the second thermal transfer layer 52 may not be peeled off during high-temperature transfer, and the color of the characters may become cloudy.

[0098] The thermoplastic elastomer contained in the intermediate layer 51 has a melt mass flow rate (hereinafter sometimes abbreviated simply as "MFR") of, for example, 1000 g / 10 min or less, and preferably 400 g / 10 min or less. The MFR may be, for example, the MFR determined by the measurement method specified in ISO 1133-1:2011, at a temperature of 190°C and a load of 2.16 kg. Hereinafter, unless otherwise specified, the conditions for measuring the MFR are a temperature of 190°C and a load of 2.16 kg.

[0099] Thermoplastic elastomers with an MFR greater than 400 g / 10 min tend to have too strong an affinity with the second thermal transfer layer 52. As a result, the second thermal transfer layer 52 may not peel off during low-temperature transfer, causing the color of the characters to become cloudy. Furthermore, the entire thermal transfer recording medium 47, i.e., the substrate layer 48, welding layer 70, first thermal transfer layer 50, intermediate layer 51, and second thermal transfer layer 52, may stick to the printing surface 31 of the printer tape 2. Thermoplastic elastomers with an MFR greater than 400 g / 10 min have low melt viscosity and high fluidity, so they may not be able to maintain adhesion to the first thermal transfer layer 50 and second thermal transfer layer 52 during low-temperature transfer, or the color of the characters may become cloudy.

[0100] In contrast, if a thermoplastic elastomer has an MFR of 400 g / 10 min or less, problems that can occur when using a thermoplastic elastomer with an MFR exceeding 400 g / 10 min can be suppressed. Furthermore, even when thermal transfer recording is performed continuously, the colors on the printing surface 31 of the printer tape 2 are not easily clouded, the two colors are clearly separated, and characters can be recorded with excellent clarity without residual peeling. To further enhance these effects, it is preferable that the MFR of the thermoplastic elastomer be 2.5 g / 10 min or less, especially 2.3 g / 10 min or less, even within the above range.

[0101] There is no particular lower limit for the MFR, and thermoplastic elastomers that show "No Flow" when measured at the aforementioned temperature of 190°C and load of 2.16 kg can be used. Specific examples of thermoplastic elastomers include, but are not limited to, the following thermoplastic elastomers. These thermoplastic elastomers can be used alone or in combination of two or more.

[0102] Among the SEBS in the Tuftec (registered trademark) series manufactured by Asahi Kasei Corporation, the following are used: 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: No Flow), 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).

[0103] Among the SBSs in the Tufprene (registered trademark) series manufactured 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].

[0104] Among the SBSs in the Asaprene (registered trademark) T series manufactured 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].

[0105] Among the SEPS in the Septon (registered trademark) series manufactured by Kuraray Co., Ltd., the following were measured: 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 was measured under the following conditions: a temperature of 230°C and a load of 2.16 kg.

[0106] Among the SEEPS in the Septon (registered trademark) series manufactured by Kuraray Co., Ltd., the following are listed: 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 measurement conditions for these SEEPS are a temperature of 230°C and a load of 2.16 kg.

[0107] Among the vinyl SISs in the Hybra (registered trademark) series manufactured by Kuraray Co., Ltd., 5125 [MFR: 4g / 10min] and 5127 [MFR: 5 / 10min].

[0108] Among the Ultrathene (registered trademark) series EVA manufactured by Tosoh Corporation, 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) in], 537 [MFR:8.5g / 10min], 537L [MFR:8.5g / 10min], 537S-2 [MFR:8.5g / 10min], 541 [MFR:9.0g / 10min] , 541L [MFR:9.0g / 10min], 530 [MFR:75g / 10min], 526 [MFR:25g / 10min], 630 [MFR:1.5g / 10min], 631 [MFR :1.5g / 10min〕, 636〔MFR:2.5g / 10min〕, 625〔MFR:14g / 10min〕, 626〔MFR:3.0g / 10min〕, 627〔MFR:0.8g / 1 0min], 633 [MFR:20g / 10min], 635 [MFR:2.4g / 10min], 640 [MFR:2.8g / 10min], 634 [MFR:4.3g / 10min], 68 0 [MFR:160g / 10min], 681 [MFR:350g / 10min], 751 [MFR:5.7g / 10min], 710 [MFR:18g / 10min], 720 [MFR:15] 0g / 10min〕, 722〔MFR:400g / 10min〕, 750〔MFR:30g / 10min〕, 752〔MFR:60g / 10min〕, 760〔MFR:70g / 10min〕.

[0109] The intermediate layer 51 can be formed, for example, by applying a coating material in which a forming material for the intermediate layer 51 containing at least a thermoplastic elastomer is dissolved or dispersed in any solvent onto the first thermal transfer layer 50 and then drying it.

[0110] The thickness of the intermediate layer 51 can be set arbitrarily depending on, for example, the specifications of the thermal transfer printer. The thickness of the intermediate layer 51 can be adjusted by the amount of application of the intermediate layer 51. For example, the amount of application of the intermediate layer 51 is 0.1 g / m2 in terms of the amount of solid content per unit area. 2 or more, and preferably 0.2 g / m 2 For example, the coating amount of the intermediate layer 51 is 2.0 g / m2 in terms of the amount of solid content per unit area. 2 and preferably 1.5 g / m 2 For example, the coating amount of the intermediate layer 51 is 0.1 g / m2 in terms of the amount of solid content per unit area. 2 More than 2.0g / m 2 or less, preferably 0.2 g / m 2 More than 1.5g / m 2 The following is the result.

[0111] A specific thickness of the intermediate layer 51 (before printing) is, for example, 0.05 μm or more, and preferably 0.2 μm or more. The thickness of the intermediate layer 51 is, for example, 2.0 μm or less, and preferably 1.5 μm or less. The thickness of the intermediate layer 51 may be, for example, 0.05 μm or more and 2.0 μm or less, and 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 scanning electron microscope (SEM) image or a transmission electron microscope (TEM) image of the thermal transfer recording medium 47.

[0112] Due to limitations in 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 may be values ​​that include such errors. For example, 0.2 g / m 2 The intermediate layer 51 formed with a coating amount of 0.1 g / m 2 It may have a region having a thickness when formed with an application amount of 1000 ppm or more.

[0113] (6) Second thermal transfer layer 52 The second thermal transfer layer 52 can be formed, for example, from any thermoplastic resin. Examples of thermoplastic resins used for the second thermal transfer layer 52 include epoxy resin, polyester resin, and polyolefin resin. The thermoplastic resin can be selected appropriately depending on the material from which the printer tape 2 is formed. When the first thermal transfer layer 50 is formed from an epoxy resin, it is preferable that the second thermal transfer layer 52 is also formed from an epoxy resin.

[0114] By forming the second thermal transfer layer 52 from an epoxy resin, the adhesive strength of the first thermal transfer layer 50 to the welding layer 70 and intermediate layer 51 can be balanced against the adhesive strength of the second thermal transfer layer 52 to the printer tape 2. This allows the first thermal transfer layer 50 and the intermediate layer 51 to be effectively separated toward the base layer 48, and the second thermal transfer layer 52 to be effectively separated toward the printer tape 2, during low-temperature transfer. Examples of epoxy resins that can be used include the various epoxy resins exemplified as epoxy resins for the first thermal transfer layer 50. These epoxy resins can be used alone or in combination of two or more types.

[0115] The second thermal transfer layer 52 may contain wax in addition to the thermoplastic resin. The inclusion of wax allows the first thermal transfer layer 50 and the intermediate layer 51 to be easily separated from each other on the substrate layer 48 side, and the second thermal transfer layer 52 to be easily separated from each other on the printer tape 2 side, during low-temperature transfer.

[0116] Any wax that has affinity or compatibility with thermoplastic resins such as epoxy resins can be used as the wax. 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 waxes are not particularly limited, but include, for example, carnauba wax No. 1 flake, No. 2 flake, No. 3 flake, No. 1 powder, and No. 2 powder manufactured by Toyochem Co., Ltd. (all of which have a melting point of 80 to 86°C), and paraffin waxes such as EMUSTAR-1155 (melting point: 69°C), EMUSTAR-0135 (melting point: 60°C), and EMUSTAR-0136 (melting point: 60°C) manufactured by Nippon Seiro Co., Ltd. Examples of suitable waxes include microcrystalline waxes manufactured by Nippon Seiro Co., Ltd., such as EMUSTAR-0001 (melting point: 84°C) and EMUSTAR-042X (melting point: 84°C), and Fischer-Tropsch waxes manufactured by Nippon Seiro Co., Ltd., such as FNP-0090 (freezing point: 90°C), SX80 (freezing point: 83°C), FT-0165 (melting point: 73°C), and FT-0070 (melting point: 72°C). These waxes can be used alone or in combination of two or more.

[0117] The second thermal transfer layer 52 may contain any colorant. As the colorant, one or more of various colorants can be used depending on the color of the second thermal transfer layer 52. The colorant may be, for example, a pigment. In consideration of improving the weather resistance of the letters, a pigment is preferred as the colorant used in the second thermal transfer layer 52. For example, the following various red pigments can be used as pigments for coloring the second thermal transfer layer 52 red. These red pigments can be used alone or in combination of two or more.

[0118] 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.

[0119] The ratio of each component in the second thermal transfer layer 52 is not particularly limited. The ratio of wax to 100 parts by mass of epoxy resin is, for example, 3 parts by mass or more, and preferably 5 parts by mass or more. The ratio of wax to 100 parts by mass of epoxy resin is, for example, 11 parts by mass or less, and preferably 9 parts by mass or less. The ratio of wax to 100 parts by mass of epoxy resin is, for example, 3 parts by mass or more and 11 parts by mass or less, and preferably 5 parts by mass or more and 9 parts by mass or less.

[0120] The ratio of the colorant such as a red pigment to 100 parts by mass of the epoxy resin is, for example, 70 parts by mass or more, and preferably 80 parts by mass or more. The ratio of the colorant such as a red pigment to 100 parts by mass of the epoxy resin is, for example, 140 parts by mass or less, and preferably 120 parts by mass or less. The ratio of the colorant such as a 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.

[0121] The second thermal transfer layer 52 can be formed, for example, by applying a coating material in which the above components are dissolved or dispersed in an arbitrary solvent onto the intermediate layer 51 and then drying the coating material.

[0122] The thickness of the second thermal transfer layer 52 can be set arbitrarily depending on, for example, the specifications of the thermal transfer printer. 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 0.2 g / m2 expressed in terms of the amount of solid content per unit area. 2 or more, and preferably 1.0 g / m 2 For example, the coating amount of the second thermal transfer layer 52 is 7.0 g / m2 in terms of the amount of solid content per unit area. 2 and preferably 5.0 g / m 2 For example, the coating amount of the second thermal transfer layer 52 is 0.2 g / m 2 in terms of the amount of solids per unit area. 2 More than 7.0g / m 2 and preferably 1.0 g / m 2 More than 5.0g / m 2 The following is the result.

[0123] The specific thickness of the second thermal transfer layer 52 (before printing) is, for example, 0.05 μm or more, and preferably 1.0 μm or more. The thickness of the second thermal transfer layer 52 is, for example, 7.0 μm or less, and preferably 5.0 μm or less. The thickness of the second thermal transfer layer 52 may be, for example, 0.05 μm or more and 7.0 μm or less, and 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 scanning electron microscope (SEM) image or a transmission electron microscope (TEM) image of the thermal transfer recording medium 47.

[0124] In the thermal transfer recording medium 47, for example, the amount of energy applied to the thermal head 6 (see FIGS. 1 and 3) may be set low to perform thermal transfer at a relatively low temperature. In this case, in this embodiment, the second thermal transfer layer 52 softens and its adhesion to the base layer 48 decreases. Meanwhile, the adhesion between the first thermal transfer layer 50 and the second thermal transfer layer 52 decreases. In this case, the welding layer 70 has a high softening point, so it hardly softens and maintains high adhesion between the base layer 48 and the first thermal transfer layer 50. As a result, during thermal transfer, only the second thermal transfer layer 52 is thermally transferred to the printing surface 31 of the printer tape 2, while the first thermal transfer layer 50 and the intermediate layer 51 remain on the base layer 48 side (reverse transfer). Therefore, the characters recorded on the printing surface 31 of the printer tape 2 will be the color of the second thermal transfer layer 52, for example, red.

[0125] On the other hand, the thermal transfer recording medium 47 may be thermally transferred at a higher temperature by applying a higher amount of energy to the thermal head 6. In this case, the welding layer 70 further softens, significantly reducing the adhesive strength between it and, for example, the base layer 48. As a result, the entire thermal transfer layer, i.e., the welding layer 70, first thermal transfer layer 50, intermediate layer 51, and second thermal transfer layer 52, are thermally transferred integrally onto the printing surface 31 of the printer tape 2. The characters recorded on the printing surface 31 of the printer tape 2 will have the color of the first thermal transfer layer 50, which is the outermost layer after transfer, for example, black.

[0126] As a result, a two-color pattern, for example, black and red, can be printed using a general-purpose thermal transfer printer that is compatible with two-color printing.

[0127] Therefore, according to the present disclosure, even when a general-purpose thermal transfer printer capable of two-color recording is used to perform continuous thermal transfer recording, the colors are not easily mixed and are clearly separated into two colors, and characters with excellent clarity can be recorded without causing residual peeling.

[0128] [Introduction of a welding layer 70 based on irreversible changes in force] FIG. 6 shows a thermal transfer recording medium 47 equipped with a welding layer 70 as an example of a thermal transfer recording medium (ink ribbon) capable of simultaneously recording characters in at least two colors with good clarity. The specific chemical composition of the welding layer 70 includes at least one resin selected from the group consisting of polyamide resin, polyester resin, epoxy resin, phenol resin, and polyvinyl alcohol resin. The inventors of the present application have also studied and implemented a thermal transfer recording medium that exhibits similar effects from a different perspective, which will be described in detail below. In short, while FIG. 6 focuses on the chemical composition of the welding layer 70, the following focuses on the irreversible change in interlayer adhesive strength caused by controlling the ultimate temperature of the thermal transfer recording medium 47.

[0129] FIG. 7 is a diagram showing the relationship between the elapsed time and the temperature reached by the thermal transfer recording medium 47 in the heating and cooling steps shown in FIGS. 1 to 4A and 4B.

[0130] The horizontal axis in FIG. 7 represents the elapsed time of the printing process of the printing device 1. t0 represents the start of printing, t1 represents the end of heating by the thermal head 6, and t2 represents the time when the ink ribbon reaches the ink ribbon peeling member 13. The vertical axis in FIG. 7 represents the temperature reached by the thermal transfer recording medium 47. The temperature reached by 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. Such external factors may include, for example, heating by the thermal head 6, natural cooling of the thermal transfer recording medium 47 while it is being transported, etc.

[0131] 7, in the printing device 1, the control circuit 22 controls the temperature output (temperature energy) of the thermal head 6, thereby controlling the temperature reached by the thermal transfer recording medium 47. For example, a relatively low first amount of 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 determined by the temperature T of the thermal transfer recording medium 47 relative to the ambient temperature (for example, room temperature) around the thermal transfer recording medium 47, as shown by the first temperature curve 55 in the dashed dotted line. E It increases exponentially from T R1 to reach.

[0132] Achieved temperature T R1 may be defined as a temperature equal to or higher than the first temperature T1 and equal to or lower than the second temperature T2. For example, the first temperature T1 is equal to or higher than 60°C and equal to or lower than 120°C, and preferably equal to or higher than 70°C and equal to or lower than 90°C. For example, the second temperature T2 is equal to or higher than 80°C and equal to or lower than 180°C, and preferably equal to or higher than 130°C and equal to or lower than 150°C. The reached temperature T R1 can be set appropriately depending on the output setting method of the thermal head 6 of the printing device 1 used. For example, the target temperature may be set in association with quantitative parameters such as the voltage or current supplied to the heating elements 20 of the thermal head 6, the energization time, etc. Alternatively, the target temperature may be set in association with a relative value to a predetermined reference value (for example, the value before energization is set to 0 (zero)).

[0133] On the other hand, in the heating step, a second energy amount relatively higher than the first energy amount is applied to the thermal head 6. In this case, the temperature of the thermal transfer recording medium 47 is, as shown by the second temperature curve 56 in solid line, equal to the ambient temperature T E It increases exponentially from T R2 The temperature reached is T R2 may be defined as the temperature above the second temperature T2.

[0134] After the heating step, the thermal transfer recording medium 47 is naturally cooled in the section up to the ink ribbon peeling member 13 (see also Fig. 3 and Figs. 4A and 4B). In the cooling step, the temperature of the thermal transfer recording medium 47 is cooled to the ultimate temperature T R1 and T R2 It decreases exponentially from T PThe temperature reached at this time is T P is the temperature at which a part of the thermal transfer recording medium 47 is peeled off by the ink ribbon peeling member 13, and is therefore the peeling temperature T P The peeling temperature T P is preferably equal to or lower than the third temperature T3. The third temperature T3 is lower than the first temperature T1 (i.e., the first temperature T1 is equal to or higher than the third temperature T3), and is, for example, 40°C to 90°C, and preferably 60°C to 80°C. The magnitudes of the first temperature T1, the second temperature T2, and the third temperature T3 can be set appropriately within the temperature range required for transfer onto the printer tape 2, taking into consideration the chemical composition and physical properties of the ink of the thermal transfer recording medium 47.

[0135] The temperature curve (cooling curve) of the thermal transfer recording medium 47 in the cooling process eventually converges to a constant temperature regardless of which heating control is performed in the heating process, as indicated by the first temperature curve 55 or the second temperature curve 56. Therefore, by ensuring a long cooling process time (t1 → t2), the peeling temperature T P can be made substantially the same. To lengthen the cooling process time, for example, the distance between the thermal head 6 and the ink ribbon peeling member 13 (peeling distance L1 in FIG. 1) can be increased. For example, the state of the thermal transfer recording medium 47 after the heating process and the cooling process are performed by the temperature change shown by the first temperature curve 55 in FIG. 7 may be defined as a first state C1. In contrast, the state of the thermal transfer recording medium 47 after the heating process and the cooling process are performed by the temperature change shown by the second temperature curve 56 in FIG. 7 may be defined as a second state C2.

[0136] In this way, in the printing device 1, by controlling the temperature output (thermal energy) of the thermal head 6, the start temperature (environment temperature T E ) and final temperature (peeling temperature T P) is kept constant, the temperature reached by the thermal transfer recording medium 47 can be varied. Taking this temperature control into consideration, for example, by controlling the temperature output of the thermal head 6 in accordance with the physical properties of the base layer 48, backing layer 49, welding layer 70, first thermal transfer layer 50, intermediate layer 51, and second thermal transfer layer 52 of the thermal transfer recording medium 47 in Figure 6, it is expected that the adhesive strength between the layers of the thermal transfer recording medium 47 can be controlled.

[0137] 8 and 9 are diagrams showing the relationship between the elapsed time in the heating process and the cooling process and the interlayer adhesive strength of the thermal transfer recording medium 47. Fig. 8 shows the change in each adhesive strength F when the temperature of the thermal transfer recording medium 47 is changed according to the first temperature curve 55 in Fig. 6. Fig. 9 shows the change in each adhesive strength F when the temperature of the thermal transfer recording medium 47 is changed according to the second temperature curve 56 in Fig. 6.

[0138] 8 and 9, the horizontal axis represents the elapsed time of the printing process of the printer 1. t0 represents the start of printing, t1 represents the end of heating by the thermal head 6, and t2 represents the arrival of the ink ribbon at the ink ribbon peeling member 13. The vertical axis in FIGS. 8 and 9 represents the strength of the adhesive force between each layer of the thermal transfer recording medium 47.

[0139] 8 and 9, 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 shown by a solid first adhesive force curve 57. The second adhesive force F2 between the base layer 48 and the first thermal transfer layer 50 is shown by a dashed-dotted second adhesive force curve 58. The first adhesive force F1 may include the force at which the intermediate layer 51 and the second thermal transfer layer 52 are separated from each other, the force at which the second thermal transfer layer 52 is internally torn, and the force at which the intermediate layer 51 is internally torn. Furthermore, in cases where the components of the first thermal transfer layer 50 and the intermediate layer 51 are mixed by melting to form a mixed layer, the first adhesive force F1 may also include the force at which the mixed layer is separated from the second thermal transfer layer 52. The second adhesive strength F2 may include the force when the bond between the base layer 48 and the welding layer 70 comes off, the force when the bond between the welding layer 70 and the first thermal transfer layer 50 comes off, the force when the first thermal transfer layer 50 breaks internally, and the force when the welding layer 70 breaks internally.

[0140] 8 and 9, both the first adhesive force F1 and the second adhesive force F2 change over time as the heating and cooling processes are performed, regardless of the amount of energy applied to the thermal head 6 during the heating process. More specifically, both the first adhesive force F1 and the second adhesive force F2 decrease as the heating time elapses, and both the first adhesive force F1 and the second adhesive force F2 increase as the cooling time after heating elapses.

[0141] The magnitude relationship between the first adhesive force F1 and the second adhesive force F2 before heating and after cooling varies depending on the amount of energy applied to the thermal head 6. For example, as shown in FIG. 8, when the amount of energy applied to the thermal head 6 is relatively low, the second adhesive force F2 is greater than the first adhesive force F1 both before heating and after cooling (first state C1). Therefore, if peeling is performed in the first state C1, the first adhesive force F1 is smaller than the second adhesive force F2, and peeling occurs between the first thermal transfer layer 50 and the second thermal transfer layer 52, and the second thermal transfer layer 52 is transferred to the printer tape 2. On the other hand, to ensure that the first adhesive force F1 is smaller than the second adhesive force F2 after cooling, it is preferable to perform the cooling process for at least a period longer than the time t3 corresponding to the intersection 59 of the first adhesive force curve 57 and the second adhesive force curve 58 shown in FIG. 9. This is because the thermal transfer recording medium 47 is sufficiently cooled, allowing for reliable cold peeling.

[0142] 9, when the amount of 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 (second state C2). Before heating, the second adhesive force F2 is greater than the first adhesive force F1, whereas after cooling (second state C2), the second adhesive force F2 is smaller than the first adhesive force F1. In other words, the first adhesive force F1 undergoes an irreversible change. Therefore, if peeling is performed in the second state C2, peeling occurs between the base layer 48 and the first thermal transfer layer 50 because the first adhesive force F1 is greater than the second adhesive force F2, and the first thermal transfer layer 50 and second thermal transfer layer 52 in an adhered state are transferred to the printer tape 2. On the other hand, to achieve the condition of first adhesive force F1 > second adhesive force F2 after cooling, it is preferable to carry out the cooling step for at least longer than time t3 corresponding to the intersection 60 of the first adhesive force curve 57 and the second adhesive force curve 58 shown in Fig. 9. This is because the thermal transfer recording medium 47 is cooled sufficiently and cold peeling can be reliably carried out.

[0143] Time t3 may be appropriately set so that the first adhesive force F1<the second adhesive force F2 after cooling of the thermal transfer recording medium 47 heated with low energy, and so that the first adhesive force F1>the second adhesive force F2 after cooling of the thermal transfer recording medium 47 heated with high energy. For example, time t3 may be the time required to lower the ultimate temperature of the thermal transfer recording medium 47 below the third temperature T3 in both cases of low energy application and high energy application. The peeling distance L1 (see FIG. 1) required to ensure time t3 is, for example, 70 mm or more and 150 mm or less, and preferably 90 mm or more and 120 mm or less.

[0144] In this way, by utilizing the irreversible change in the first adhesive force F1 that occurs depending on the amount of energy applied to the thermal head 6, it is possible to freely control the peeling position of the thermal transfer recording medium 47, and to provide a thermal transfer recording medium 47 that can simultaneously record characters in at least two colors with good clarity.

[0145] (1) Peeling mode of thermal transfer recording medium 47 10 to 17 are diagrams showing the state of peeling of the thermal transfer recording medium 47. First, how the thermal transfer recording medium 47 peels depending on the magnitude relationship between the first adhesive force F1 and the second adhesive force F2 will be described with reference to FIGS. 10 to 17. With reference to FIGS. 10 to 17, there are several peeling modes for the thermal transfer recording medium 47. The peeling modes in FIGS. 10 to 17 may be referred to as first to eighth peeling modes, respectively. From the perspective of the energy supplied to the thermal head 6, a distinction can be made between a low-energy peeling mode shown in FIGS. 10 to 13 and a high-energy peeling mode shown in FIGS. 14 to 17.

[0146] 10 to 13 show peeling modes when peeling (thermal transfer) is performed in the first state C1 via heating control (low energy application) of the first temperature curve 55 in FIG. 7. In the first peeling mode of FIG. 10, the breaking strength (first adhesive force F1) between the intermediate layer 51 and the second thermal transfer layer 52 becomes the smallest in the thermal transfer recording medium 47 in the first state C1, and peeling occurs at their interface. In the second peeling mode of FIG. 11, the breaking strength (first adhesive force F1) in the second thermal transfer layer 52 becomes the smallest in the thermal transfer recording medium 47 in the first state C1, and peeling occurs inside the second thermal transfer layer 52. In the third peeling mode of FIG. 12, the breaking strength (first adhesive force F1) in the intermediate layer 51 becomes the smallest in the thermal transfer recording medium 47 in the first state C1, and peeling occurs inside the intermediate layer 51. In the fourth peeling mode of FIG. 13, 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. The breaking strength (first adhesive force F1) between the mixed layer 61 and the second thermal transfer layer 52 is the smallest within the thermal transfer recording medium 47, and peeling occurs at the interface between them. The first peeling mode of FIG. 10 and the fourth peeling mode of FIG. 13 are interfacial failures, while the second peeling mode of FIG. 11 and the third peeling mode of FIG. 12 are cohesive failures. In any of the peeling modes of FIGS. 10 to 13, the second thermal transfer layer 52 is transferred to the printer tape 2.

[0147] 14 to 17 show peeling modes when peeling (thermal transfer) is performed in the second state C2 via heating control (high energy application) of the second temperature curve 56 in Fig. 7. The peeling modes in Fig. 14 to 17 can be divided into at least two types: interfacial failure and cohesive failure, similar to the first to fourth peeling modes.

[0148] 14, in the second state C2, the breaking strength (second adhesive force F2) between the base layer 48 and the welding layer 70 becomes the smallest in the thermal transfer recording medium 47, and peeling occurs at their interface (interfacial failure). In the sixth peeling mode of Fig. 15, in the second state C2, the breaking strength (second adhesive force F2) between the welding layer 70 and the first thermal transfer layer 50 becomes the smallest in the thermal transfer recording medium 47, and peeling occurs at their interface (interfacial failure).

[0149] 16, in the second state C2, the breaking strength (second adhesive force F2) in the first thermal transfer layer 50 becomes the smallest in the thermal transfer recording medium 47, and peeling occurs inside the first thermal transfer layer 50 (cohesive failure). In the eighth peeling mode of FIG. 17, in the second state C2, the breaking strength (second adhesive force F2) in the welding layer 70 becomes the smallest in the thermal transfer recording medium 47, and peeling occurs inside the welding layer 70 (cohesive failure).

[0150] In any of the peeling modes shown in FIGS. 14 to 17, the first thermal transfer layer 50 and the second thermal transfer layer 52 in an adhered state are selectively transferred to the printer tape 2.

[0151] 10 to 17, it can be confirmed by, for example, observing a cross section of the thermal transfer recording medium 47 after rupture, based on, for example, an SEM (Scanning Electron Microscope) image, a TEM (Transmission Electron Microscope) image, or the like of the thermal transfer recording medium 47 after rupture.

[0152] As described above, in the first to fourth peeling modes, the characters recorded on the printing surface 31 of the printer tape 2 have the color of the second thermal transfer layer 52, for example, red. In the fifth to eighth peeling modes, the characters recorded on the printing surface 31 of the printer tape 2 have the color of the first thermal transfer layer 50, for example, black.

[0153] Therefore, to provide a thermal transfer recording medium 47 capable of simultaneously recording characters of at least two colors with good clarity, at least one of the first to fourth peeling modes must be achieved during heating control (low energy application) of the first temperature curve 55, and at least one of the fifth to eighth peeling modes must be achieved during heating control (high energy application) of the second temperature curve 56. To achieve these, the conditions for each layer of the thermal transfer recording medium 47 were examined from the following multiple perspectives.

[0154] (2) Chemical composition of each layer of thermal transfer recording medium 47 In terms of the chemical composition of each layer of thermal transfer recording medium 47, the chemical compositions of base layer 48, back surface layer 49, welding layer 70, first thermal transfer layer 50, intermediate layer 51, and second thermal transfer layer 52 shown in the section "Introduction of welding layer 70" above are preferred. Naturally, thermal transfer recording medium 47 having this chemical composition has welding layer 70 containing at least one resin selected from the group consisting of polyamide resin, polyester resin, epoxy resin, phenol resin, and polyvinyl alcohol resin, and therefore can simultaneously record characters in at least two colors with good clarity by temperature control under conditions typical of general-purpose thermal transfer printers, regardless of the temperature control shown in FIG.

[0155] 7, other compositions may be used in addition to the thermoplastic elastomer described above for 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.

[0156] An example of the polyolefin resin is Surflen (registered trademark) P-1000 manufactured by Mitsubishi Chemical Corporation.

[0157] Examples of long-chain alkyl resins include 1010, 1010S, 1050, 1070, 406, and the like, from the Piroil (registered trademark) series manufactured by Lion Specialty Chemicals Co., Ltd.

[0158] By providing the welding layer 70 and intermediate layer 51 containing the resins exemplified above, it is possible to provide a thermal transfer recording medium 47 that can simultaneously record characters in at least two colors with good clarity.

[0159] (3) Solubility parameter (SP value) of each layer of thermal transfer recording medium 47 In terms of the physical properties of each layer of the thermal transfer recording medium 47, attention is focused on the relative relationship between the solubility parameters (SP values) and softening points of the constituent components of each layer. By adjusting the SP values ​​and softening points of the constituent components of each layer, it is possible to control the interlayer adhesion and internal peeling of the thermal transfer recording medium 47. The closer the SP values ​​of the constituent components that are in contact with each other, the easier they will adhere (high affinity), and the greater the SP values, the easier they will peel (low affinity). Therefore, by adjusting the balance of the SP values ​​and content ratios 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. This provides a thermal transfer recording medium 47 that can simultaneously record characters in at least two colors with good clarity.

[0160] Hereinafter, when showing a relative relationship (magnitude relationship) between SP values, it is sufficient that the calculation conditions for the SP values ​​being compared are the same. For example, the SP value may be an HSP value (Hansen solubility parameter) or an SP value (Hildebrand solubility parameter). Furthermore, there are no particular limitations on the method for calculating the SP value, and it may be, for example, a method of determining it from the latent heat of vaporization, a method using the Hildebrand Rule, a method of estimating it from physical property values ​​such as a method using surface tension, or a method of estimating it from molecular structure such as the Small calculation method, the Fedors calculation method, the Hansen calculation method, or the Hoy calculation method. In addition, in this disclosure, when a range or specific numerical value of the SP value is shown, the SP value is the SP value (Hildebrand solubility parameter) unless otherwise specified.

[0161] FIG. 18 is a diagram for comparing the solubility parameters (SP values) of the constituent materials of a thermal transfer recording medium 47 according to an embodiment of the present disclosure.

[0162] 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 has a relatively low SP value and softening point compared to the second material 63. The SP value of the first material 62 is, for example, 7.5 to 9.5, and preferably 8.0 to 9.0. Examples of the first material 62 include the adhesives and tackifiers exemplified as components of the first thermal transfer layer 50 in the above-mentioned "(Introduction of the welding layer 70)".

[0163] The second material 63 is a material that has a relatively high SP value and softening point compared to the first material 62. The SP value of the second material 63 is, for example, 9.0 to 12.0, and preferably 10.0 to 11.0. The softening point of the second material 63 is, for example, 60°C or higher and 150°C or lower, and preferably 90°C or higher and 145°C or lower. Examples of the second material 63 include the thermoplastic resins exemplified as components of the first thermal transfer layer 50 in the above-mentioned "(Introduction of the welding layer 70)".

[0164] 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, and preferably 45 parts by mass or more, of the first material 62 per 100 parts by mass of the second material 63. For example, 300 parts by mass or less, and preferably 200 parts by mass or less, of the first material 62 per 100 parts by mass of the second material 63. For example, 30 parts by mass or more and 300 parts by mass or less, and preferably 45 parts by mass or more and 200 parts by mass or less, of the first material 62 per 100 parts by mass of the second material 63.

[0165] 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, and preferably 8.0 to 9.0. Examples of the third material 64 include the thermoplastic elastomers exemplified in the above-mentioned "(Introduction of the welding layer 70)", as well as polyolefin resins and long-chain alkyl resins.

[0166] The second thermal transfer layer 52 is composed of at least a fourth material 65 and a fifth material 66. The fourth material 65 has a relatively high SP value and softening point compared to the fifth material 66. The SP value of the fourth material 65 is, for example, 9.0 to 12.0, and preferably 10.0 to 11.0. The softening point of the fourth material 65 is, for example, 60°C or higher and 150°C or lower, and preferably 90°C or higher and 145°C or lower. Examples of the fourth material 65 include the thermoplastic resins exemplified as components of the second thermal transfer layer 52 in the above-mentioned "(Introduction of the welding layer 70)".

[0167] The fifth material 66 is a material having a relatively low SP value and softening point compared to the fourth material 65. The SP value of the fifth material 66 is, for example, 7.5 to 9.5, and preferably 8.0 to 9.0. The melting point of the fifth material 66 is, for example, 60°C or higher and 120°C or lower, and preferably 65°C or higher and 100°C or lower. Examples of the fifth material 66 include waxes and the like exemplified as components of the second thermal transfer layer 52 in the above-mentioned "(Introduction of the welding layer 70)".

[0168] 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, and preferably 5 parts by mass or more, of the fifth material 66 per 100 parts by mass of the fourth material 65. For example, the weight ratio of the fifth material 66 is 11 parts by mass or less, and preferably 9 parts by mass or less, per 100 parts by mass of the fourth material 65. For example, the weight ratio of the fifth material 66 is 3 parts by mass or more and 11 parts by mass or less, and preferably 5 parts by mass or more and 9 parts by mass or less, per 100 parts by mass of the fourth material 65.

[0169] The welding layer 70 is composed of at least a sixth material 67. The sixth material 67 has a relatively high SP value and softening point compared to the material of the base layer 48 and the second material 63. The SP value of the sixth material 67 is, for example, 9.0 to 14.0, and preferably 12.0 to 14.0. The sixth material 67 may be at least one selected from the group consisting of polyamide resins, polyester resins, epoxy resins, phenolic resins, and polyvinyl alcohol resins, which are exemplified above in "(Introduction of welding layer 70)".

[0170] Examples of materials for the base layer 48 include the resin films exemplified above in the section "(Introduction of the welding layer 70)", condenser paper, thin paper such as glassine paper, and cellophane.

[0171] To summarize the relative relationships between the SP values ​​and the softening points, first, the SP values ​​of the first material 62, the third material 64, and the fourth material 65 are smaller than those of the second material 63, the fifth material 66, and the sixth material 67. The SP values ​​of the second material 63 and the fifth material 66 are also smaller than that of the sixth material 67. The softening points of the first material 62, the fourth material 65, and the fifth material 66 are lower than those of the second material 63 and the third material 64. The softening points of the second material 63 and the third material 64 are also lower than that of the sixth material 67, and the softening points of the third material 64 and the sixth material 67 are lower than that of the base layer 48.

[0172] FIG. 19 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.

[0173] As mentioned above, examples of materials that can be used as the first to sixth materials 62 to 67 have been given, but the materials to be used are not particularly limited as long as the relative relationship (magnitude relationship) of the SP values ​​in the thermal transfer recording medium 47 is as described above. For example, appropriate materials can be selected with reference to the magnitude relationship shown in Figure 19. In doing so, it should be taken into account that materials with similar SP values ​​tend to adhere more easily, and materials with different SP values ​​tend to peel more easily.

[0174] For example, for the first thermal transfer layer 50, a terpene phenol resin may be selected as the first material 62, and an epoxy resin may be selected as the second material 63. For example, for the intermediate layer 51, a thermoplastic elastomer, polyolefin, or the like may be selected as the third material 64. For example, for the second thermal transfer layer 52, a wax may be selected as the fourth material 65, and an epoxy resin may be selected as the fifth material 66. For example, for the welding layer 70, a polyamide resin with a particularly high SP value may be selected as the sixth material 67.

[0175] As described above, by combining the SP values ​​as described above, at least one of the first to fourth peeling modes can be achieved during heating control (low energy application) of the first temperature curve 55 in Figure 7, and at least one of the fifth to eighth peeling modes can be achieved during heating control (high energy application) of the second temperature curve 56.

[0176] For example, the amount of energy applied to the thermal head 6 (see FIGS. 1 and 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, reducing its adhesion to the base layer 48. Meanwhile, the adhesion between the first thermal transfer layer 50 and the second thermal transfer layer 52 decreases. Because the welding layer 70 has a high softening point, it barely softens, maintaining high adhesion between the base layer 48 and the first thermal transfer layer 50. This is because the sixth material 67 of the welding layer 70 has a relatively high SP value, which increases its cohesive force and increases its softening point. As a result, during thermal transfer, only the second thermal transfer layer 52 is thermally transferred to the printing surface 31 of the printer tape 2, while the first thermal transfer layer 50 and the intermediate layer 51 remain on the base layer 48 (reverse transfer). Therefore, the characters recorded on the printing surface 31 of the printer tape 2 will be the color of the second thermal transfer layer 52, for example, red. That is, in low temperature transfer, at least one of the first to fourth peeling modes can be achieved.

[0177] On the other hand, the thermal transfer recording medium 47 is thermally transferred at a higher temperature by applying a higher amount of energy to the thermal head 6. In this case, the welding layer 70 further softens, significantly reducing the adhesive strength between the welding layer 70 and, for example, the base layer 48. As a result, the entire thermal transfer layer, i.e., the welding layer 70, first thermal transfer layer 50, intermediate layer 51, and second thermal transfer layer 52, are thermally transferred integrally to the printing surface 31 of the printer tape 2. The characters recorded on the printing surface 31 of the printer tape 2 will be the color of the first thermal transfer layer 50, which is the outermost layer after transfer, for example, black. In other words, high-temperature transfer can achieve at least one of the fifth to eighth peeling modes. As a result, a thermal transfer recording medium 47 can be provided that can simultaneously record characters in at least two colors with good clarity. [Example]

[0178] The present disclosure will be further explained below based on experimental examples, but the configuration of the present disclosure is not limited to these examples.

[0179] [Coating material for first thermal transfer layer (I)] The components shown in Table 1 below were dissolved in a mixed solvent of toluene and methyl ethyl ketone (MEK) in a mass ratio of 1 / 4 to prepare a coating material (I) for the first thermal transfer layer with a solids concentration of 22.5 mass%. The proportion of the active ingredient in the acrylic adhesive was 80 mass parts per 100 mass parts of epoxy resin.

[0180] [Table 1]

[0181] The components in the table are as follows:

[0182] Epoxy resin: JER1007 manufactured by Mitsubishi Chemical Corporation [basic solid type, softening point (ring and ball method): 128°C, number average molecular weight Mn: approximately 2900, SP value: 9.5 to 11.5] Acrylic adhesive: AS-665 manufactured by Lion Specialty Chemicals Co., Ltd. [Solid content: 40% by mass, SP value: 8.0-9.5] Tackifier: Terpene phenol resin, YS Polyster T80 manufactured by Yasuhara Chemical Co., Ltd. (softening point: 80±5°C, SP value: 8.0 to 9.0) Carbon black: MA100 powder manufactured by Mitsubishi Chemical Corporation (LFF, DBP absorption: 100 cm 3 / 100g [Coating material for welding layer (1)] A polyamide resin (Tomaido 1315 manufactured by T&K TOKA Corporation, 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 coating material (1) for the welding layer with a solids concentration of 10% by mass.

[0183] [Coating material for welding layer (2)] A polyvinyl alcohol resin (Denka Poval B-05 manufactured by Denka Co., Ltd., SP value: 12.60, softening point: 200°C) was dissolved in water to prepare a coating material for welding layer (2) with a solid content concentration of 10% by mass.

[0184] [Coating material for welding layer (3)] 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 coating material (3) for the welding layer with a solids concentration of 10 mass%.

[0185] [Coating material for welding layer (4)] 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 coating material (4) for the welding layer with a solids concentration of 10% by mass.

[0186] [Coating material for welding layer (5)] 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 coating material (5) for the welding layer with a solids concentration of 10 mass%.

[0187] The material names, SP values, and softening points of the welding layer coating materials (1) to (5) are summarized in Table 2 below. The mixing ratio of the components is omitted because the solid content / solvent ratio for all of the intermediate layer coating materials (1) to (5) is 10 / 90.

[0188] [Table 2]

[0189] [Coating material for intermediate layer (1)] A thermoplastic elastomer (Tuftec H1521, SEBS, manufactured by Asahi Kasei Corporation, MFR: 12.3 g / 10 min, styrene content: 18% by mass, SP value: 7.5 to 9.0) was dissolved in a mixed solvent of toluene and hexane in a mass ratio of 1:1 to prepare a coating material (1) for the intermediate layer with a solids concentration of 10% by mass.

[0190] [Coating material for intermediate layer (2)] Intermediate layer coating material (2) was prepared in the same manner as intermediate layer coating material (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 blended as the thermoplastic elastomer. The solid content was 10% by mass.

[0191] [Coating material for intermediate layer (3)] Intermediate layer coating material (3) was prepared in the same manner as 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 blended as the thermoplastic elastomer. The solid content was 10% by mass.

[0192] [Coating material for intermediate layer (4)] Intermediate layer coating material (4) was prepared in the same manner as intermediate layer coating material (1), except that the same amount of Tuftec H1221 (SEBS, MFR: less than 4.5 g / 10 min, styrene content 12% by mass, SP value: 7.5 to 9.0) manufactured by Asahi Kasei Corporation was blended as the thermoplastic elastomer. The solid content was 10% by mass.

[0193] [Coating material for intermediate layer (5)] The intermediate layer coating material (5) was prepared in the same manner as the intermediate layer coating material (1), except that the same amount of Tuftec H1043 (SEBS, MFR: less than 2.0 g / 10 min, styrene content 67% by mass, SP value: 7.5 to 9.0) manufactured by Asahi Kasei Corporation was blended as the thermoplastic elastomer. The solid content was 10% by mass.

[0194] [Coating material for intermediate layer (6)] The intermediate layer coating material (6) was prepared in the same manner as the intermediate layer coating material (1), except that the same amount of Tufprene A (SBS, MFR: 2.6 g / 10 min, styrene content 40% by mass, SP value: 7.5 to 9.0) manufactured by Asahi Kasei Corporation was blended as the thermoplastic elastomer. The solid content was 10% by mass.

[0195] [Coating material for intermediate layer (7)] Intermediate layer coating material (7) was prepared in the same manner as intermediate layer coating material (1), except that the same amount of Ultrathene 634 (EVA, MFR: 4.3 g / 10 min, SP value: 7.5 to 9.0) manufactured by Tosoh Corporation was blended as the thermoplastic elastomer. The solid content was 10% by mass.

[0196] [Coating material for intermediate layer (8)] Intermediate layer coating material (8) was prepared in the same manner as intermediate layer coating material (1), except that the same amount of Ultrathene 722 (EVA, MFR: 400 g / 10 min, SP value: 7.5 to 9.0) manufactured by Tosoh Corporation was blended as the thermoplastic elastomer. The solid content was 10% by mass.

[0197] [Coating material for intermediate layer (9)] Intermediate layer coating material (9) was prepared in the same manner as intermediate layer coating material (1), except that the same amount of Ultrathene 725 (EVA, MFR: 1000 g / 10 min, SP value: 7.5 to 9.0) manufactured by Tosoh Corporation was blended as the thermoplastic elastomer. The solid content was 10% by mass.

[0198] [Coating material for intermediate layer (10)] Intermediate layer coating material (10) was prepared in the same manner as intermediate layer coating material (1), except that the same amount of Ultrathene 684 (EVA, MFR: 2000 g / 10 min, SP value: 7.5 to 9.0) manufactured by Tosoh Corporation was blended as the thermoplastic elastomer. The solid content was 10% by mass.

[0199] [Coating material for intermediate layer (11)] An intermediate layer coating material (11) was prepared in the same manner as the intermediate layer coating material (1), except that the thermoplastic elastomer was replaced with the same amount of modified polyolefin resin (Surfren (registered trademark) P-1000, manufactured by Mitsubishi Chemical Corporation, SP value: 7.5 to 8.5). The solid content was 10% by mass.

[0200] The material names, MFR, and styrene contents of intermediate layer coating materials (1) to (11) are summarized in Table 3 below. The blending ratio of the components is omitted because the solid content / toluene / hexane = 10 / 45 / 45 for all intermediate layer coating materials (1) to (11).

[0201] [Table 3]

[0202] [Coating material for second thermal transfer layer (I)] Each component shown in Table 4 below was dissolved in a mixed solvent of toluene and MEK in a mass ratio of 1 / 4 to prepare a coating material (I) for second thermal transfer layer with a solids concentration of 28 mass %.

[0203] [Table 4]

[0204] The components in the table are as follows:

[0205] Epoxy resin: JER1004 manufactured by Mitsubishi Chemical Corporation [basic solid type, softening point (ring and ball method): 97°C, number average molecular weight Mn: approximately 1650, SP value: 10.0 to 11.0] Wax: Carnauba wax No. 2 powder manufactured by Toyochem Co., Ltd. (melting point: 80-86°C, SP value: 7.0-9.0) Red pigment: CI Pigment Red 53:1 (SYMULER® Lake Red C-102, manufactured by DIC Corporation) [Experimental Examples 1-21] (1) Manufacturing of thermal transfer recording media First, a PET film having a thickness of 4.5 μm was prepared as a substrate layer. Next, a silicone resin having a solid content per unit area of ​​0.1 g / m was applied to the surface (back side) of the substrate layer opposite to the surface on which the thermal transfer layer was formed. 2 Next, one of the previously prepared coating materials for the welding layer was applied to the surface of the base layer and then dried to form a back surface layer having a solid content per unit area of ​​0.4 g / m. 2Next, the first thermal transfer layer coating material prepared above was applied to the surface of the welding layer and then dried to form a welding layer having a solid content per unit area of ​​1.7 g / m. 2 A first thermal transfer layer was formed. Next, if necessary, one of the intermediate layer coating materials prepared previously was applied on the first thermal transfer layer and then dried to form an intermediate layer. Regarding the amount of coating material applied for the intermediate layer, in Experimental Examples 1 to 16, the solid content per unit area was 1 g / m 2 The results for Experimental Examples 18 to 21 are shown in Table 9 below. Next, the previously prepared second thermal transfer layer coating material (I) was applied onto the intermediate layer or the first thermal transfer layer and then dried to a solid content per unit area of ​​2.5 g / m 2 A thermal transfer recording medium was manufactured by forming a second thermal transfer layer of the formula: The composition of each layer of the thermal transfer recording media obtained in Experimental Examples 1 to 21 is as shown in Tables 5 to 9 below. In the tables, NF in the column for the binder in the intermediate layer stands for No Flow. (2) Evaluation (2-1) Continuous Recording Evaluation The thermal transfer recording medium produced in each experimental example was slit into ribbons of a specified 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 were as follows: <Resolution> 300dpi line thermal head <Resistance of heating element> 1830Ω <Transfer load> 30N / 2inch <Transport speed> 20mm / sec <Peeling distance> 110mm Next, at an ambient temperature of 25°C, the thermal transfer printer's preset thermal head energy settings were set to low energy (0.25 mJ / dot: 25 V (0.34 W / dot) / 750 μsec, black) or high energy (0.34 mJ / dot: 25 V (0.34 W / dot) / 1000 μsec, red). A 70 mm square solid image was recorded 20 times continuously on the surface of a variable information label material (polyester film (white, glossy), Lintec Corporation, FR1415-50, SP value: 10.7, softening point: 240°C). If slight cloudiness was observed during recording, the continuous printing was terminated at that point, and the number of black or red prints was recorded as the continuous print count. In the evaluation, experiments in which black was printed even after the 20th print were considered to have excellent continuous printability for 20 or more prints, while experiments in which cloudiness occurred after the third print or less were considered to be insufficient for practical use. The results are shown in Tables 5 to 9. (2-2) Evaluation of recording clarity The thermal transfer recording medium produced in each experimental example was slit into ribbons of a specified width, wound into a roll, and loaded into a thermal transfer printer (a prototype printer manufactured by Brother Industries, Ltd.) with the same specifications as in (2-1). Next, in an ambient temperature of 25°C, the energy value applied to the thermal head, which was preset in the thermal transfer printer, was set to low energy (0.25 mJ / dot: 25 V (0.34 W / dot) / 750 μsec, black) or high energy (0.34 mJ / dot: 25 V (0.34 W / dot) / 1000 μsec, red), and a barcode was recorded on the surface of a variable information printing label material (polyester film (white, glossy), FR1415-50 manufactured by Lintec Corporation, SP value: 10.7, softening point: 240°C). The recorded barcode was then read using a barcode verifier (Laser Examiner Elite IS manufactured by Munazowo Co., Ltd.), and the decodability grade specified in the American National Standards Institute (ANSI X3.182-1990) was calculated from the results, and the clarity of the recording was evaluated according to the following criteria. ○: The decodability grade for both black and red was A [excellent] or B [good]. △: The decodability grade of either black or red was C [good], and the other was C [good] or better. ×: At least one of the black and red colors had a decodability grade of D (fair) or F (poor).

[0206] The results are shown in Tables 5 to 9. Among Experimental Examples 1 to 17, Experimental Examples 1 to 16 and Experimental Examples 18 to 21 are examples, and Experimental Example 17 may be a comparative example. (2-3) Observation of fracture location The thermal transfer recording medium produced in each experimental example was slit into ribbons 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 in (2-1). Next, in an environment with an outside temperature of 25°C, the energy value applied to the thermal head, which was preset in the thermal transfer printer, was set to low energy (0.25 mJ / dot: 25 V (0.34 W / dot) / 750 μsec, and the temperature reached T R1 : 80℃, black) and high energy (0.34mJ / dot: 25V (0.34W / dot) / 1000μsec, reached temperature T R2 A 70mm square solid image was recorded on the surface of a variable information printing label material (polyester film (white, glossy), Lintec Corporation's FR1415-50, SP value: 10.7, softening point: 240°C) by placing the labels separately in a thermal printer (heat treatment temperature: 140°C, red). In both cases, the thermal transfer printer's peel distance was set to 110mm, allowing the labels to be sufficiently cooled (to below 60°C) before the peeling process. The cross-section of the resulting solid image was observed using a transmission electron microscope (TEM: Hitachi High-Tech Corporation HT7820, accelerating voltage 100kV). The location of fractures on the thermal transfer recording medium was confirmed for both the black and red transfers. The fracture locations were classified according to the peeling mode as follows:

[0207] First peeling mode: Between the intermediate layer and the second thermal transfer layer (interface failure; see Figure 10) Second peel mode: Inside the second thermal transfer layer (cohesive failure, see Figure 11) Third delamination mode: Inside the interlayer (cohesive failure, see Figure 12) Fourth peeling mode: Between the mixed layer and the second thermal transfer layer (interface failure; see Figure 13) Fifth peeling mode: Between the substrate layer and the welded layer (interface failure; see Figure 14) Peeling mode 6: Between the adhesive layer and the first thermal transfer layer (interface failure; see Figure 15) Seventh peel mode: Inside the first thermal transfer layer (cohesive failure; see Figure 16) 8th peeling mode: Inside the welded layer (cohesive failure, see Figure 17) The results are shown in Tables 5 to 9. In Tables 5 to 9, the first to eighth peeling modes are each indicated by a circled number. In Tables 5 to 9, when multiple peeling modes are shown, this indicates that different peeling modes occurred in the in-plane direction of the thermal transfer recording medium. Furthermore, since Experimental Examples 6 and 17 had layer structures without an intermediate layer, the peeling modes in the lower rows of Table 6 were, strictly speaking, cohesive failures occurring in the state in which the intermediate layer 51 was omitted from Figures 11 and 13.

[0208] [Table 5]

[0209] [Table 6]

[0210] [Table 7]

[0211] [Table 8]

[0212] [Table 9]

[0213] A comparison of Experimental Examples 1 to 16 in Tables 5 to 8 with Experimental Example 17 reveals that the desired peeling mode can be achieved by adjusting the balance of the SP values ​​of the components of the welding layer, first thermal transfer layer, second thermal transfer layer, and intermediate layer, for example, with reference to Figure 17. As a result, it was found that a thermal transfer recording medium was obtained in which the colors were clearly separated into two colors without mixing even when thermal transfer recording was performed continuously, and characters could be recorded with excellent clarity without causing residual peeling.

[0214] Comparing Experimental Examples 1 to 4 with Experimental Example 5, it was found that the SP value of the welding layer is particularly preferable to be 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 enabled continuous recording of 10 or more times to be achieved.

[0215] A comparison of Experimental Examples 1 and 6 revealed that it is preferable to provide an intermediate layer between the first and second thermal transfer layers, which makes it possible to provide a thermal transfer recording medium that is excellent in both continuous recording and clarity.

[0216] A comparison of Experimental Examples 7 to 15 with Experimental Example 16 reveals that, in order to further improve continuous recording properties and clarity, it is preferable to use a thermoplastic elastomer for the intermediate layer.

[0217] Furthermore, the results of Experimental Examples 1 and 7 to 15 showed that preferred thermoplastic elastomers for forming the intermediate layer are EVA, SBS, SEBS, etc. Furthermore, in order to further improve continuous recording properties, it was found that 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.

[0218] Experimental Examples 1 and 18 to 21 showed that practically sufficient continuous recording properties and clarity can be achieved even when the coating amount of the intermediate layer is changed. Of Experimental Examples 1 and 18 to 21, Experimental Examples 1, 19, and 20 were found to be particularly excellent in continuous recording properties and clarity. In Experimental Examples 1, 19, and 20, the intermediate layer is the thinnest (lowest coating amount) of the layers constituting the thermal transfer recording medium, and the thickness (coating amount) of the intermediate layer is large enough to fully realize the effects of introducing the intermediate layer.

[0219] In other words, in Experimental Example 21, the intermediate layer was not the thinnest but relatively thick among the layers constituting the thermal transfer recording medium, resulting in a large transfer area (excess peeling) and reduced image clarity. Normally, as in Experimental Example 21, increasing the thickness of one of the adjacent layers closer to the heat source reduces the temperature reached at the interface between that layer and the other layer, which is thought to result in a reduced transfer area. However, at the interface between the intermediate layer and the second thermal transfer layer, a decrease in the interface temperature can result in a phenomenon in which the adhesive strength between the intermediate layer and the second thermal transfer layer (between "51" and "52" in Figure 6) remains relatively low. As a result, the adhesive strength between the intermediate layer and the second thermal transfer layer was relatively weaker than the adhesive strength between the label material and the second thermal transfer layer (between "2" and "52" in Figure 6) at the edge of the barcode, which is thought to have caused rupture between the intermediate layer and the second thermal transfer layer and increased excess peeling.

[0220] On the other hand, in Experimental Example 18, the intermediate layer was the thinnest of the layers constituting the thermal transfer recording medium, but the coating amount was 0.1 g / m 2 Because the amount was so small, the intermediate layer was unable to fully fulfill its original role, and a decrease in both continuous recording ability and clarity was confirmed. [Explanation of symbols]

[0221] 1:Printing device 2: Printer tape 3: Ink ribbon 6: Thermal head 20: Heating element 31:Print surface 32: Back side 35: Base material layer 36: First ink layer 37: Second ink layer 42 :1st part 43:Second part 44: Printing pattern 45: Red pattern 46: Black pattern 47: Thermal transfer recording medium 48: Base material layer 50: 1st thermal transfer layer 51: Middle class 52:Second thermal transfer layer 61:Mixed layer 62: 1st material 63:Second material 64:Third material 65: 4th material 66: 5th material 67: 6th material 70: Welding layer F1: External force T1: 1st temperature T2: Second temperature T3: 3rd temperature T R1 :Achieved temperature T R2 :Achieved temperature

Claims

1. a substrate layer having a first surface and a second surface; a welding layer made of a resin, a first thermal transfer layer, and a second thermal transfer layer, which are laminated in this order on the first surface of the base layer in direct contact with each other, The thermal transfer recording medium, wherein the welding layer has a solubility parameter (SP value) higher than the solubility parameters (SP values) of the base layer and the first thermal transfer layer.

2. A thermal transfer recording medium as described in claim 1, wherein the welding layer does not contain wax.

3. The thermal transfer recording medium according to claim 2, wherein the welding layer is made of a resin having a solubility parameter (SP value) of 9.0 to 14.

0.

4. The thermal transfer recording medium according to any one of claims 1 to 3, wherein the welding layer contains at least one resin selected from the group consisting of polyamide-based resins, polyester-based resins, epoxy-based resins, phenol-based resins, and polyvinyl alcohol-based resins.

5. 4. The thermal transfer recording medium according to claim 1, wherein the first thermal transfer layer contains an epoxy resin and an acrylic adhesive.

6. 4. The thermal transfer recording medium according to claim 1, wherein the second thermal transfer layer contains a thermoplastic resin and a wax.

7. The welding layer contains at least one resin selected from the group consisting of polyamide resins, polyester resins, epoxy resins, phenolic resins, and polyvinyl alcohol resins, and does not contain wax; the first thermal transfer layer includes an epoxy resin and an acrylic adhesive; the second thermal transfer layer comprises a thermoplastic resin and a wax; The thermal transfer recording medium according to any one of claims 1 to 3, wherein the softening point of the welding layer is greater than the softening point of the first thermal transfer layer and greater than the softening point of the second thermal transfer layer.

8. The thermal transfer recording medium according to any one of claims 1 to 3, wherein the softening point of the welding layer is lower than the softening point of the base layer and is the same as or higher than the softening point of the first thermal transfer layer.

9. A thermal transfer recording medium comprising a substrate layer, a fusing layer containing a fusing material, a first ink layer containing a first ink, and a second ink layer containing a second ink laminated in this order, wherein at least a portion of the first ink layer and the second ink layer is thermally transferred to a print-receiving medium, when an external force is applied to the base layer and the second ink layer in a direction away from each other in a first state in which the thermal transfer recording medium is heated to a temperature equal to or higher than a first temperature and a temperature equal to or lower than a second temperature and then cooled to a temperature equal to or lower than a third temperature, the thermal transfer recording medium is broken between the first ink layer and the second ink layer or within the second ink layer, when the external force is applied in a second state in which the thermal transfer recording medium is heated to a temperature exceeding the second temperature and then cooled to a third temperature or lower, the thermal transfer recording medium is broken between the first ink layer and the base layer or within the first ink layer, The thermal transfer recording medium, wherein the first temperature is higher than the third temperature.

10. 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 among the thermal transfer recording media, 10. The thermal transfer recording medium according to claim 9, wherein 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 among the thermal transfer recording media.

11. The thermal transfer recording medium according to claim 9 or 10, wherein when the external force is applied in the second state, the thermal transfer recording medium is broken between the welding layer and the base layer.

12. The thermal transfer recording medium according to claim 11 , wherein when the external force is applied in the second state, the breaking strength between the welding layer and the base layer is the smallest among the thermal transfer recording media.

13. 11. The thermal transfer recording medium according to claim 9, wherein the softening point of the welding layer is lower than that of the substrate layer and is equal to or higher than that of the first ink layer.

14. 11. The thermal transfer recording medium according to claim 9, wherein the welding layer has a solubility parameter (SP value) higher than the solubility parameters (SP values) of the base layer and the first ink layer.

15. 11. The thermal transfer recording medium according to claim 9, wherein the welding layer contains at least one resin selected from the group consisting of polyamide resins, polyester resins, epoxy resins, phenol resins, and polyvinyl alcohol resins.

16. The thermal transfer recording medium according to claim 9 or 10, further comprising an intermediate layer formed between the first ink layer and the second ink layer.

17. The thermal transfer recording medium according to claim 16, wherein when the external force is applied in the first state, the thermal transfer recording medium is torn between the intermediate layer and the second ink layer.

18. The thermal transfer recording medium according to claim 17 , wherein when the external force is applied in the first state, the breaking strength between the intermediate layer and the second ink layer is the smallest in the thermal transfer recording medium.

19. The thermal transfer recording medium according to claim 17, wherein the intermediate layer comprises a styrene-based thermoplastic elastomer.

20. 20. The thermal transfer recording medium according to claim 19, wherein the styrene-based thermoplastic elastomer comprises at least one of a styrene-butadiene-styrene block copolymer (SBS) and a styrene-ethylene-butene-styrene block copolymer (SEBS).

21. 21. The thermal transfer recording medium according to claim 20, wherein the styrene content in the styrene-based thermoplastic elastomer is 10% by mass to 70% by mass.

22. The thermal transfer recording medium according to claim 17, wherein the intermediate layer comprises an acetate-based thermoplastic elastomer.

23. 23. The thermal transfer recording medium according to claim 22, wherein the acetate-based thermoplastic elastomer includes ethylene-vinyl acetate copolymer (EVA).

24. 17. The thermal transfer recording medium according to claim 16, wherein in the first state, the first ink layer and the intermediate layer are mixed together.

25. The thermal transfer recording medium according to claim 16, wherein the intermediate layer is broken when the external force is applied in the first state.

26. 26. The thermal transfer recording medium according to claim 25, wherein when the external force is applied in the first state, the intermediate layer has the smallest breaking strength of the thermal transfer recording medium.

27. 26. The thermal transfer recording medium according to claim 25, wherein the intermediate layer contains at least one of a polyolefin resin and a long-chain alkyl resin.

28. the first ink layer includes at least a first material and a second material; the intermediate layer comprises a third material; the second ink layer includes a fourth material and a fifth material; the welding layer includes a sixth material; solubility parameters (SP values) of the first material, the third material, and the fifth material are smaller than solubility parameters (SP values) of the second material, the fourth material, and the sixth material; The thermal transfer recording medium according to claim 16, wherein 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.

29. The first material includes an acrylic adhesive, the second material includes an epoxy resin; the third material includes a thermoplastic elastomer; the fourth material includes a thermoplastic resin; the fifth material includes a wax; 29. The thermal transfer recording medium according to claim 28, wherein the sixth material 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.

30. the first state is a state in which the base layer of the thermal transfer recording medium is heated to a temperature equal to or higher than the first temperature and equal to or lower than the second temperature, and then cooled to a temperature equal to or lower than the third temperature; 11. The thermal transfer recording medium according to claim 9, wherein the second state is a state in which the base layer of the thermal transfer recording medium is heated to a temperature exceeding the second temperature and then cooled to a temperature equal to or lower than the third temperature.

31. a heating step of heating a thermal transfer recording medium, in which 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 are laminated in this order, while the thermal transfer recording medium is in contact with a print medium; a cooling step of cooling the thermal transfer recording medium heated in the heating step; a transfer step of transferring at least a portion of the first ink and the second ink to the print medium by applying an external force in a direction away from the base layer and the second ink layer of the thermal transfer recording medium cooled by the cooling step, In the heating step and the cooling step, a first portion of the thermal transfer recording medium is heated to a temperature equal to or higher than a first temperature and equal to or lower than a second temperature, and then cooled to a third temperature or lower to form a first state; and a second portion of the thermal transfer recording medium is heated to a temperature higher than the second temperature, and then cooled to a third temperature or lower to form a second state; In the transfer step, By applying the external force, the thermal transfer recording medium is broken between the first ink layer and the second ink layer or within the second ink layer in the first portion of the thermal transfer recording medium, and the second ink is transferred to the printing medium; By applying the external force, the thermal transfer recording medium is broken between the first ink layer and the base layer or within the first ink layer in the second portion of the thermal transfer recording medium, and the first ink and the second ink are transferred to the print medium; The printing device, wherein the first temperature is greater than the third temperature.

32. A thermal transfer recording medium according to claim 1 or 9; a cassette containing a print-receiving medium onto which a portion of the thermal transfer recording medium is thermally transferred;

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