Uv-cured ink for thermal transfer ribbons, method of making the same, and thermal transfer ribbons

Abstract

The application provides a UV curing ink for a thermal transfer ribbon and a preparation method of the UV curing ink and the thermal transfer ribbon, and relates to the technical field of thermal transfer printing. The UV curing ink is mainly prepared by compounding active oligomer monomers, a photo initiator, pigments, additives and fillers according to specific proportions. The Tg value of the UV curing ink after curing is 65-80 DEG C. Meanwhile, the UV curing ink is combined with a release layer and adheres to the release layer to form a new functional coating layer during curing. Through the selection of the above raw materials and the compounding according to specific proportions, the ink can be in a liquid state and a low viscosity state during preparation, and can be in a solid state at normal temperature after preparation. The ink can be peeled from a base material by heating, and can be transferred to a medium such as a label paper by a bar code printer. In addition, since the UV curing ink has a low Tg value, the transfer temperature is low, and the transferred bar code and font have good definition and are easy to identify.

Description

Technical Field

[0001] This invention relates to the field of heat transfer technology, and in particular to a UV-curable ink for heat transfer ribbons, a method for preparing the ink, and a heat transfer ribbon. Background Technology

[0002] Thermal transfer ribbons are printing consumables used in the computer industry. A computer signal drives a semiconductor heating head to transfer heat to the print head. When the printing medium and the thermal transfer ribbon pass through the printer's print head and pressure roller, under certain temperature and pressure conditions, the ink on the ribbon melts and transfers to the printing medium, completing the printing process. Thermal transfer printing offers advantages such as high speed, high resolution, good resistance, continuous printing of variable information, and applicability to various printing media. It is widely used in industrial and other fields for printing barcodes, dates, and product information.

[0003] Existing heat transfer ribbons are categorized by their formulation into wax-based, mixed-based, and resin-based ribbons. Except for some wax-based ribbons, mixed-based and resin-based ribbons utilize large amounts of organic solvents in their formulation and manufacturing processes. Public data shows that the solvent content in mixed-based and resin-based ribbons ranges from 40% to 80%, and is removed during production through drying. This solvent drying process generates VOCs, which are primarily emitted through RTO catalytic combustion, causing significant environmental pressure. Furthermore, existing wax-based heat transfer ribbons, mainly composed of wax and resin, lack sufficient scratch resistance, limiting their application range.

[0004] In recent years, UV-curable inks have been widely used in inkjet printing and other fields due to their advantages in photocuring. Because direct printing produces images, existing technologies typically require optimizing the material's molecular weight to improve its resistance. This results in a high molecular weight and high Tg value in the UV-cured resin, which is the opposite of the requirements for resin materials in thermal transfer ribbons. Thermal transfer ribbons require two transfers and printing processes (the ink is coated onto a PET substrate during manufacturing; when used in products, the ink on the PET substrate is transferred to labels or other media). A higher Tg value requires higher energy for transfer and printing, making the process more difficult and resulting in poor image clarity, such as unreadable barcodes.

[0005] Therefore, it is both necessary and urgent to research and develop a UV-curable heat transfer ribbon that does not contain organic solvents and whose ink layer has a low Tg value after curing, so as to fully meet the requirements of the heat transfer ribbon for two-stage transfer and printing.

[0006] In view of this, the present invention is hereby proposed. Summary of the Invention

[0007] The primary objective of this invention is to provide a UV-curable ink for heat transfer ribbons, wherein the ink has the advantage of a low Tg value, resulting in a lower transfer temperature, better clarity of transfer and printing, and easier recognition of barcodes and fonts.

[0008] The second objective of this invention is to provide a method for preparing UV-curable ink for heat transfer ribbons.

[0009] A third objective of this invention is to provide a heat transfer ribbon, wherein the ink layer of the heat transfer ribbon is mainly prepared by UV curing of the aforementioned UV-curable ink for heat transfer ribbons.

[0010] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0011] This invention provides a UV-curable ink for heat transfer ribbons, wherein the UV-curable ink comprises, by weight percentage:

[0012] The composition includes 60-75% reactive oligomer monomers, 5-15% photoinitiator, 10-20% pigment, 0.5-8% additives, and 0.1-0.5% filler.

[0013] The UV-curable ink has a Tg value of 65–80°C after UV curing.

[0014] Furthermore, by weight percentage, the UV-curable ink comprises:

[0015] The composition includes 71% reactive oligomer monomers, 10% photoinitiator, 15% pigment, 3.9% additives, and 0.1% filler.

[0016] Furthermore, the active oligomer monomer includes at least one of phenolic modified epoxy acrylate, difunctional polyurethane acrylate, trifunctional polyurethane acrylate, difunctional polyester acrylate, and mercapto modified polyester acrylate resin.

[0017] Furthermore, the photoinitiator includes at least one of TPO-L photoinitiator, 907 photoinitiator, OMBB photoinitiator, 54 photoinitiator, and EDB photoinitiator;

[0018] Preferably, the photoinitiator comprises at least one of 2,4,6-trimethylbenzoylphosphonate, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-acetone, methyl o-benzoylbenzoate, a mixture of benzoyl esters, and ethyl 4-dimethylaminobenzoate.

[0019] Furthermore, the additives include at least one of diluents, leveling agents, and dispersants;

[0020] Preferably, the diluent comprises at least one of ethoxylated trimethylolpropanetriol triacrylate, propoxylated trimethylolpropanetriol triacrylate, propoxylated glycerol triacrylate G(PO)TA, 1,6-hexanediol methoxy monoacrylate, and ethoxylated neopentyl glycol methoxy monoacrylate.

[0021] Preferably, the leveling agent includes at least one of polyacrylate leveling agents, polymethylsiloxane leveling agents, and cellulose acetate butyrate.

[0022] Preferably, the dispersant comprises at least one of polyalkylammonium salt copolymers, long-chain fatty acid dispersants, and acrylic copolymer dispersants.

[0023] Furthermore, the pigment includes at least one of carbon black, pigment red, pigment blue, and silica powder;

[0024] The filler includes at least one of silicon dioxide, calcium carbonate, barium sulfate, talc, etc.

[0025] This invention provides a method for preparing UV-curable ink for heat transfer ribbons, the method comprising:

[0026] After mixing all the raw materials of the photoinitiator, disperse and grind them until the fineness of the pigment and filler is 0.2-2 μm. Then add the photoinitiator and mix well to obtain a UV-curable ink for heat transfer ribbon.

[0027] The ink layer has a coating thickness of 1.5–2 μm, and the UV curing irradiation dose is 90 mJ / cm. 2 .

[0028] The present invention provides a heat transfer ribbon, which comprises, from bottom to top, a back coating layer, a substrate layer, a release layer and an ink layer;

[0029] The ink layer is mainly prepared by UV curing of the UV-curable ink used for heat transfer ribbons.

[0030] Furthermore, the release layer is mainly composed of wax and resin, with a wax to resin mass ratio of 80-90:10-20, wherein:

[0031] The waxes include at least one of palm wax, saxoline wax, candelilla wax, rice bran wax, and nutshell wax; lignite wax, Fischer-Tropsch wax, polyethylene wax, and polypropylene wax.

[0032] The resin includes at least one of polyacrylic acid resin, EVA resin, polyurethane resin, phenolic resin, rosin resin, linear SBS, and linear SEBS.

[0033] Furthermore, the substrate layer is a BOPET film with a thickness of 3.5–4.5 μm;

[0034] The back coating is a UV-cured silicone back coating;

[0035] Preferably, the back coating thickness is 1–2 μm, and the UV curing UV irradiation dose is 50 mJ / cm. 2 .

[0036] Furthermore, the coating thickness of the ink layer is 1.5–2 μm; the UV irradiation dose for UV curing of the ink layer is 90 mJ / cm. 2 .

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] The present invention provides a UV-curable ink for heat transfer ribbons, wherein the ink is mainly composed of active oligomer monomers, photoinitiators, pigments, additives, and fillers compounded in a specific ratio. This application utilizes the active oligomer monomers and photoinitiators to form a polymer, effectively controlling the molecular weight of the polymer, resulting in a Tg value of 65-80°C after UV curing. Simultaneously, the ink prepared by the specific compounding of the above-mentioned raw materials has a low viscosity (50-300 mPa·s), allowing for better dispersion of pigments and fillers and facilitating subsequent coating. Therefore, the UV-curable ink for heat transfer ribbons of this application features a low Tg value and low viscosity. Its liquid and low-viscosity state during preparation allows for better incorporation of pigments and other materials into the ink, while the ink remains solid at room temperature after preparation. Furthermore, the low Tg value of the ink results in a lower transfer temperature, better clarity in transfer and printing, and easier identification of barcodes and fonts.

[0039] This invention provides a method for preparing UV-curable ink for heat transfer ribbons. The method involves first mixing and dispersing all raw materials except the photoinitiator until the pigment and filler have a fineness of 0.2–2 μm. Then, the photoinitiator is added and mixed thoroughly to obtain the UV-curable ink for heat transfer ribbons. This application controls the fineness of the pigment and filler to 0.2–2 μm through dispersion and grinding. The ink prepared at this fineness exhibits excellent cohesiveness. Verification has shown that the heat transfer properties, clarity, and scratch resistance of the heat transfer ribbons prepared using this method are all superior.

[0040] The thermal transfer ribbon provided by this invention comprises, from bottom to top, a back coating layer, a substrate layer, a release layer, and an ink layer; wherein the ink layer is mainly prepared by UV curing the aforementioned UV-curable ink used for the thermal transfer ribbon. Due to the performance of the UV-curable ink of this application, the thermal transfer ribbon of this application has the technical advantages of lower transfer temperature, better transfer and printing clarity, and easier recognition of barcodes and fonts. Detailed Implementation

[0041] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] According to one aspect of the present invention, a UV-curable ink for heat transfer ribbons, comprising, by weight percentage:

[0043] The composition includes 60-75% reactive oligomer monomers, 5-15% photoinitiator, 10-20% pigment, 0.5-8% additives, and 0.1-0.5% filler.

[0044] The UV-curable ink has a Tg value of 65–80°C after UV curing.

[0045] The present invention provides a UV-curable ink for heat transfer ribbons, wherein the ink is mainly composed of active oligomer monomers, photoinitiators, pigments, additives, and fillers compounded in a specific ratio. This application utilizes the active oligomer monomers and photoinitiators to form a polymer, effectively controlling the molecular weight of the polymer, resulting in a Tg value of 65-80°C after UV curing. Simultaneously, the ink prepared by the specific compounding of the above-mentioned raw materials has a low viscosity (50-300 mPa·s), allowing for better dispersion of pigments and fillers and facilitating subsequent coating. Therefore, the UV-curable ink for heat transfer ribbons of this application features a low Tg value and low viscosity. Its liquid and low-viscosity state during preparation allows for better incorporation of pigments and other materials into the ink, while the ink remains solid at room temperature after preparation. Furthermore, the low Tg value of the ink results in a lower transfer temperature, better clarity in transfer and printing, and easier identification of barcodes and fonts.

[0046] It should be noted that the reason for choosing reactive oligomer monomers in this application is as follows: First, reactive oligomer monomers are liquid oligomers and photosensitive resins, therefore they can react and cure under the action of light of specific wavelengths and energy. Simultaneously, because they are liquid oligomers, pigments and fillers can be dispersed within the reactive oligomer monomers, while other resins are usually solid or elastomers. Although some resins are liquid, they generally have negative Tg values ​​and do not react or cure under the action of light of specific wavelengths and energy.

[0047] In a preferred embodiment of the present invention, the UV-curable ink comprises, by weight percentage:

[0048] The composition includes 71% reactive oligomer monomers, 10% photoinitiator, 15% pigment, 3.9% additives, and 0.1% filler.

[0049] In this invention, the technical effect of the UV-curable ink is further optimized by further adjusting and optimizing the proportion of each component raw material.

[0050] In a preferred embodiment of the present invention, the active oligomer monomer includes at least one of phenolic modified epoxy acrylate, difunctional polyurethane acrylate, trifunctional polyurethane acrylate, difunctional polyester acrylate, and mercapto modified polyester acrylate resin.

[0051] It should be noted that the present invention does not impose any special restrictions on the source of the above-mentioned active oligomer monomers; any raw materials known to those skilled in the art can be used. For example, commercially available products can be used, or preparation methods known to those skilled in the art can be used to prepare them in-house.

[0052] In a preferred embodiment of the present invention, the photoinitiator includes at least one of TPO-L photoinitiator, 907 photoinitiator, OMBB photoinitiator, 54 photoinitiator, and EDB photoinitiator;

[0053] Preferably, the photoinitiator comprises at least one of 2,4,6-trimethylbenzoylphosphonate, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-acetone, methyl o-benzoylbenzoate, a mixture of benzoyl esters, and ethyl 4-dimethylaminobenzoate.

[0054] As a preferred embodiment, the above-mentioned photoinitiator is in liquid form, which can effectively reduce the viscosity of the ink, and at the same time, no odor is generated during the curing process, making it more environmentally friendly.

[0055] In a preferred embodiment of the present invention, the additive includes at least one of a diluent, a leveling agent, and a dispersant;

[0056] Preferably, the diluent comprises at least one of ethoxylated trimethylolpropanetriol triacrylate, propoxylated trimethylolpropanetriol triacrylate, propoxylated glycerol triacrylate G(PO)TA, 1,6-hexanediol methoxy monoacrylate, and ethoxylated neopentyl glycol methoxy monoacrylate.

[0057] Preferably, the leveling agent includes at least one of polyacrylate leveling agents, polymethylsiloxane leveling agents, and cellulose acetate butyrate.

[0058] Preferably, the dispersant comprises at least one of polyalkylammonium salt copolymers, long-chain fatty acid dispersants, and acrylic copolymer dispersants.

[0059] In a preferred embodiment of the present invention, the pigment includes at least one of carbon black, pigment red, pigment blue, and silica powder;

[0060] The filler includes at least one of silicon dioxide, calcium carbonate, barium sulfate, talc, etc.

[0061] According to one aspect of the present invention, a method for preparing a UV-curable ink for a heat transfer ribbon, the method comprising:

[0062] After mixing all the raw materials of the photoinitiator, disperse and grind them until the fineness of the pigment and filler is 0.2-2 μm. Then add the photoinitiator and mix well to obtain a UV-curable ink for heat transfer ribbon.

[0063] This invention provides a method for preparing UV-curable ink for heat transfer ribbons. The method involves first mixing and dispersing all raw materials except the photoinitiator until the pigment and filler have a fineness of 0.2–2 μm. Then, the photoinitiator is added and mixed thoroughly to obtain the UV-curable ink for heat transfer ribbons. This application controls the fineness of the pigment and filler to 0.2–2 μm through dispersion and grinding. The ink prepared at this fineness exhibits excellent cohesiveness. Verification has shown that the heat transfer properties, clarity, and scratch resistance of the heat transfer ribbons prepared using this method are all superior.

[0064] It should also be noted that the fineness of the pigments and fillers in the inks of this application has a significant impact on the opacity of the heat transfer ribbon. For example, with carbon black, the smaller the particle size, the better the opacity and blackness (while larger than 2µm, the opacity is poor). However, the fineness cannot be infinitely small (it should not be less than 0.2µm). On the one hand, this is determined by the original particle size of the carbon black, which cannot be infinitely small; on the other hand, the smaller the particle size, the greater the overall viscosity of the ink, making subsequent coating inconvenient, or even impossible.

[0065] According to one aspect of the present invention, a heat transfer ribbon comprises, from bottom to top: a back coating layer, a substrate layer, a release layer and an ink layer;

[0066] The ink layer is mainly prepared by UV curing of the UV-curable ink used for heat transfer ribbons.

[0067] The thermal transfer ribbon provided by this invention comprises, from bottom to top, a back coating layer, a substrate layer, a release layer, and an ink layer; wherein the ink layer is mainly prepared by UV curing the aforementioned UV-curable ink used for the thermal transfer ribbon. Due to the performance of the UV-curable ink of this application, the thermal transfer ribbon of this application has the technical advantages of lower transfer temperature, better transfer and printing clarity, and easier recognition of barcodes and fonts.

[0068] In a preferred embodiment of the present invention, the release layer is mainly composed of wax and resin, and the mass ratio of wax to resin is 80-90:10-20.

[0069] In a preferred embodiment, the release layer prepared by the above-mentioned wax and resin mass ratio exhibits superior resistance, thus imparting better scratch resistance to the heat transfer ribbon. Furthermore, the release layer of this application is applied via a hot-melt process, while the ink layer is cured via UV curing. Therefore, during the coating process, the release layer does not dissolve in the ink layer, resulting in clearly defined layers in each coating of the heat transfer ribbon.

[0070] Preferably, the wax includes at least one of palm wax, saxoline wax, candelilla wax, rice bran wax, and nutshell wax; lignite wax, Fischer-Tropsch wax, polyethylene wax, and polypropylene wax.

[0071] Preferably, the resin comprises at least one selected from polyacrylic acid resin, EVA resin, polyurethane resin, phenolic resin, rosin resin, linear SBS, and linear SEBS.

[0072] In a preferred embodiment of the present invention, the coating thickness of the release layer is 0.4–0.8 g / m. 2 .

[0073] In a preferred embodiment of the present invention, the substrate layer is a BOPET film with a thickness of 3.5 to 4.5 μm;

[0074] The back coating is a UV-cured silicone back coating;

[0075] It should be noted that the back coating, substrate layer, release layer and ink layer in the heat transfer ribbon of this application do not contain solvents (the release layer and ink layer are both resin layers), so there is no need to evaporate the solvent by drying during the production process, and no volatile VOCs are generated.

[0076] In a preferred embodiment of the present invention, the coating thickness of the back coating is 1–2 μm, and the UV irradiation dose for UV curing is 50 mJ / cm.2 .

[0077] In a preferred embodiment of the present invention, the coating thickness of the ink layer is 1.5–2 μm; the UV irradiation dose for UV curing of the ink layer is 90 mJ / cm. 2 .

[0078] The technical solution of the present invention will be further described below with reference to the embodiments.

[0079] Note: The raw materials used in the following examples and comparative examples are as follows:

[0080]

[0081] Example 1

[0082] A method for preparing a heat transfer ribbon, the method comprising:

[0083] (I) Preparation of ink layer materials, release layer materials and back coating materials:

[0084] 1. Prepare the ink layer ink from the following mass of raw materials per 100 parts:

[0085] 70.5 parts of monofunctional polyurethane acrylate; 8.5 parts of TPO-L; 2 parts of 907 photoinitiator; 12 parts of carbon black; 5 parts of 1,6-hexanediol methoxy monoacrylate; 1 part of fluorocarbon modified polyacrylate; 0.8 parts of acrylic copolymer dispersant; 0.2 parts of silica.

[0086] Preparation method of ink layer: Weigh each component according to the above proportion, heat the active oligomer monomer, control the temperature at 55±5℃, add dispersant, and add pigment and filler while stirring. Mix evenly, control the disperser speed at 1000 rpm, and disperse at high speed for 3 hours; perform sand milling, control the temperature at 55±5℃, the sand mill speed at 500 rpm, and the flow rate at 8 kg / min. When the material fineness reaches 0.5 μm, stop sand milling, add photoinitiator, dissolve, stir and disperse, control the disperser speed at 600 rpm, and disperse for 1 hour. Control the material temperature at 40±5℃ to obtain the ink layer.

[0087] 2. Based on 100 parts of raw material, prepare the release layer material from the following mass of raw materials:

[0088] Wax: Carnauba wax (Brazilian T3 flakes), 70 parts; Sasol wax (Sasol China Chemical Co., Ltd.), 20 parts.

[0089] Resins: Polyacrylic acid resin (Pioneer MB-256), 3 parts; EVA resin (Lotte Chemical EVA600, Korea), 5 parts; Linear SBS (TAIPOL 4270, Taiwan, China), 2 parts.

[0090] Release layer material preparation method: According to the formula, heat the above wax to 135℃ and melt it completely; add resin, set the disperser speed to 1100 rpm, disperse for 3 hours until the resin is completely melted, keep the material temperature at 115±5℃, and wait for use.

[0091] 3. Prepare a back coating material from the following quantities of raw materials per 100 parts:

[0092] Cationic UV back coating (Shin-Etsu Corporation) main agent X-62-7660, 80 parts; viscosity modifier (Shin-Etsu Corporation X-62-7680), 20 parts.

[0093] Preparation method of back coating material: Mix the materials evenly according to the ratio, and control the material temperature at 25-35℃ to obtain the final product.

[0094] (II) Preparation of heat transfer ribbon:

[0095] 1. The back coating material described in this embodiment is coated onto a BOPET base film, and the UV irradiation dose is 50 mJ / cm. 2 The coating is cured into a film to obtain the back coating.

[0096] The thickness of the back coating is 1.5 ± 0.1 μm;

[0097] 2. The release layer material described above in this embodiment is coated onto a 4.5µm BOPET base film using a coating machine, with the coating thickness controlled at 0.8±0.1µm. The film is then dried at 25-35°C to obtain the release layer.

[0098] 3. Apply the ink layer described in this embodiment, and cure it into a film after UV irradiation at a dose of 90 mJ / cm2, controlling the coating thickness to 1.6 ± 0.2 μm to obtain the ink layer.

[0099] 4. After being wound up into a master roll, the master roll is then divided into smaller rolls to prepare the UV-curable heat transfer ribbon of this embodiment.

[0100] Example 2

[0101] A method for preparing a heat transfer ribbon, the method comprising:

[0102] (I) Preparation of ink layer materials, release layer materials and back coating materials:

[0103] 1. Prepare the ink layer ink from the following mass of raw materials per 100 parts:

[0104] 71 parts of monofunctional polyurethane acrylate; 10 parts of TPO-L; 15 parts of carbon black; 2.9 parts of 1,6-hexanediol methoxy monoacrylate; 1 part of acrylate leveling agent; 0.1 parts of silica.

[0105] Ink preparation method for ink layer: same as in Example 1.

[0106] 2. Based on 100 parts of raw material, prepare the release layer material from the following mass of raw materials:

[0107] Wax: Carnauba wax (Brazilian T3 flakes), 60 parts; Sasol wax (Sasol China Chemical Co., Ltd.), 10 parts.

[0108] Resins: 15 parts of polyacrylic acid resin (Pioneer MB-256); 13 parts of EVA resin (Lotte Chemicals VA600, Korea); and 2 parts of linear SBS (TAIPOL 4270, Taiwan, China).

[0109] Release layer material preparation method: same as in Example 1.

[0110] 3. Same as Example 1.

[0111] (II) Preparation of heat transfer ribbon: Same as in Example 1.

[0112] Example 3

[0113] A method for preparing a heat transfer ribbon, the method comprising:

[0114] (I) Preparation of ink layer materials, release layer materials and back coating materials:

[0115] 1. Prepare the ink layer ink from the following mass of raw materials per 100 parts:

[0116] 75 parts of monofunctional polyurethane acrylate; 7 parts of TPO-L; 5 parts of EDB photoinitiator; 10 parts of carbon black; 2.9 parts of acrylic copolymer dispersant; 0.1 parts of silica.

[0117] Ink preparation method for ink layer: same as in Example 1.

[0118] 2. Same as Example 1.

[0119] 3. Same as Example 1.

[0120] (II) Preparation of heat transfer ribbon: Same as in Example 1.

[0121] Example 4

[0122] A method for preparing a heat transfer ribbon, the method comprising:

[0123] (I) Preparation of ink layer materials, release layer materials and back coating materials:

[0124] 1. Prepare the ink layer ink from the following mass of raw materials per 100 parts:

[0125] 60 parts of trifunctional polyester acrylate; 6 parts of TPO-L; 6 parts of EDB photoinitiator; 1.8 parts of 907 photoinitiator; 18 parts of carbon black; 6.2 parts of acrylic copolymer dispersant; 1.8 parts of acrylate leveling agent; 0.2 parts of silica.

[0126] Ink preparation method for ink layer: same as in Example 1.

[0127] 2. Same as Example 1.

[0128] 3. Same as Example 1.

[0129] (II) Preparation of heat transfer ribbon: Same as in Example 1.

[0130] Example 5

[0131] A method for preparing a heat transfer ribbon, the method comprising:

[0132] (I) Preparation of ink layer materials, release layer materials and back coating materials:

[0133] 1. Prepare the ink layer ink from the following mass of raw materials per 100 parts:

[0134] 67 parts of difunctional polyurethane acrylate; 5 parts of trifunctional polyester acrylate; 5 parts of EDB photoinitiator; 5 parts of 907 photoinitiator; 15 parts of pigment red; 2.8 parts of fluorocarbon modified polyacrylate leveling agent; 0.2 parts of silica.

[0135] Ink preparation method for ink layer: same as in Example 1.

[0136] 2. Based on 100 parts of raw material, prepare the release layer material from the following mass of raw materials:

[0137] Wax: Carnauba wax (Brazilian T3 flakes), 60 parts; Sasol wax (Sasol China Chemical Co., Ltd.), 10 parts.

[0138] Resins: Polyacrylic acid resin (Pioneer MB-256), 15 parts; Phenolic resin (Kreutz 540), 5 parts; EVA resin (Lotte Chemicals VA600), 13 parts; Linear SBS (TAIPOL 4270), 2 parts.

[0139] Release layer material preparation method: same as in Example 1.

[0140] 3. Same as Example 1.

[0141] (II) Preparation of heat transfer ribbon: Same as in Example 1.

[0142] Example 6

[0143] A method for preparing a heat transfer ribbon, the method comprising:

[0144] (I) Preparation of ink layer materials, release layer materials and back coating materials:

[0145] 1. Prepare the ink layer ink from the following mass of raw materials per 100 parts:

[0146] Difunctional polyurethane acrylate: 69.5 parts; TPO-L photoinitiator: 3 parts; EDB photoinitiator: 8 parts; 907 photoinitiator: 4 parts; Pigment red: 11 parts; 1,6-hexanediol methoxy monoacrylate: 3 parts; acrylate leveling agent: 1 part; silica: 0.5 parts.

[0147] Ink preparation method for ink layer: same as in Example 1.

[0148] 2. Same as Example 1.

[0149] 3. Same as Example 1.

[0150] (II) Preparation of heat transfer ribbon: Same as in Example 1.

[0151] Example 7

[0152] A method for preparing a heat transfer ribbon, the method comprising:

[0153] (I) Preparation of ink layer materials, release layer materials and back coating materials:

[0154] 1. Prepare the ink layer ink from the following mass of raw materials per 100 parts:

[0155] 3 parts of difunctional polyurethane acrylate; 65 parts of trifunctional polyester acrylate; 5 parts of TPO-L photoinitiator; 20 parts of silica powder; 6 parts of acrylic copolymer dispersant; 0.9 parts of acrylate leveling agent; 0.1 parts of silica.

[0156] Ink preparation method for ink layer: same as in Example 1.

[0157] 2. Same as Example 1.

[0158] 3. Same as Example 1.

[0159] (II) Preparation of heat transfer ribbon: Same as in Example 1.

[0160] Example 8

[0161] A method for preparing a heat transfer ribbon, the method comprising:

[0162] (I) Preparation of ink layer materials, release layer materials and back coating materials:

[0163] 1. Prepare the ink layer ink from the following mass of raw materials per 100 parts:

[0164] 30 parts of monofunctional polyurethane acrylate; 40 parts of difunctional polyurethane acrylate; 5 parts of trifunctional polyester acrylate; 5 parts of TPO-L photoinitiator; 8 parts of EDB photoinitiator; 11.4 parts of silica powder; 0.5 parts of acrylic copolymer dispersant; 0.1 parts of silica.

[0165] Ink preparation method for ink layer: same as in Example 1.

[0166] 2. Same as Example 1.

[0167] 3. Same as Example 1.

[0168] (II) Preparation of heat transfer ribbon: Same as in Example 1.

[0169] Comparative Example 1

[0170] A method for preparing a heat transfer ribbon, the method comprising:

[0171] (I) Preparation of ink layer materials, release layer materials and back coating materials:

[0172] 1. Prepare the ink layer ink from the following mass of raw materials per 100 parts:

[0173] 75.6 parts of monofunctional polyurethane acrylate; 6 parts of TPO-L photoinitiator; 10 parts of EDB photoinitiator; 8 parts of carbon black; 0.4 parts of 1,6-hexanediol methoxy monoacrylate.

[0174] Ink preparation method for ink layer: same as in Example 1.

[0175] 2. Same as Example 1.

[0176] 3. Same as Example 1.

[0177] (II) Preparation of heat transfer ribbon: Same as in Example 1.

[0178] Comparative Example 2

[0179] A method for preparing a heat transfer ribbon, the method comprising:

[0180] (I) Preparation of ink layer materials, release layer materials and back coating materials:

[0181] 1. Prepare the ink layer ink from the following mass of raw materials per 100 parts:

[0182] 51 parts of monofunctional polyurethane acrylate; 16 parts of TPO-L; 22 parts of carbon black; 9 parts of 1,6-hexanediol methoxy monoacrylate; 1 part of fluorocarbon modified polyacrylate leveling agent; 1 part of silica.

[0183] Ink preparation method for ink layer: same as in Example 1.

[0184] 2. Same as Example 1.

[0185] 3. Same as Example 1.

[0186] (II) Preparation of heat transfer ribbon: Same as in Example 1.

[0187] Comparative Example 3

[0188] A method for preparing a heat transfer ribbon, the method comprising:

[0189] (I) Preparation of ink layer materials, release layer materials and back coating materials:

[0190] 1. Prepare the ink layer ink from the following mass of raw materials per 100 parts:

[0191] 58 parts of trifunctional polyester acrylate; 7 parts of TPO-L; 10 parts of EDB photoinitiator; 22 parts of carbon black; 3 parts of silica.

[0192] Ink preparation method for ink layer: same as in Example 1.

[0193] 2. Same as Example 1.

[0194] 3. Same as Example 1.

[0195] (II) Preparation of heat transfer ribbon: Same as in Example 1.

[0196] Comparative Example 4

[0197] A method for preparing a heat transfer ribbon, the method comprising:

[0198] (I) Preparation of ink layer materials, release layer materials and back coating materials:

[0199] 1. Prepare the ink layer ink from the following mass of raw materials per 100 parts:

[0200] 55 parts of monofunctional polyurethane acrylate; 8 parts of TPO-L; 10 parts of EDB photoinitiator; 3 parts of 907 photoinitiator; 21 parts of pigment red; 0.4 parts of acrylic copolymer dispersant; 2.6 parts of silica.

[0201] Ink preparation method for ink layer: same as in Example 1.

[0202] 2. Same as Example 1.

[0203] 3. Same as Example 1.

[0204] (II) Preparation of heat transfer ribbon: Same as in Example 1.

[0205] Comparative Example 5

[0206] A method for preparing a heat transfer ribbon, the method comprising:

[0207] (I) Preparation of ink layer materials, release layer materials and back coating materials:

[0208] 1. The raw material composition of the ink layer is the same as in Example 1;

[0209] Preparation method of ink layer: Weigh each component according to the above proportion, heat the active oligomer monomer, control the temperature at 55±5℃, add dispersant, and add pigment and filler while stirring. Mix evenly, control the speed of the disperser at 1000 rpm, and disperse at high speed for 3 hours; perform sand milling at 1000 rpm and a flow rate of 6 kg / min, and measure the fineness of the material to be 0.15 μm. Stop sand milling, add photoinitiator, dissolve, stir and disperse, control the speed of the disperser at 600 rpm, and disperse for 1 hour, controlling the material temperature at 40±5℃ to obtain the ink layer.

[0210] 2. Same as Example 1.

[0211] 3. Same as Example 1.

[0212] (II) Preparation of heat transfer ribbon: Same as in Example 1.

[0213] Comparative Example 6

[0214] A method for preparing a heat transfer ribbon, the method comprising:

[0215] (I) Preparation of ink layer materials, release layer materials and back coating materials:

[0216] 1. The raw material composition of the ink layer is the same as in Example 1;

[0217] Preparation method of ink layer: Weigh each component according to the above proportion, heat the active oligomer monomer, control the temperature at 55±5℃, add dispersant, and add pigment and filler while stirring. Mix evenly, control the disperser speed at 1000 rpm, and disperse at high speed for 3 hours; perform sand milling, control the temperature at 55±5℃, the sand mill speed at 500 rpm, and the flow rate at 16 kg / min. The fineness of the material is measured to be 2.3 μm. Stop sand milling, add photoinitiator, dissolve, stir and disperse, control the disperser speed at 600 rpm, and disperse for 1 hour. Control the material temperature at 40±5℃ to obtain the ink layer.

[0218] 2. Same as Example 1.

[0219] 3. Same as Example 1.

[0220] (II) Preparation of heat transfer ribbon: Same as in Example 1.

[0221] Comparative Example 7

[0222] A method for preparing a heat transfer ribbon, the method comprising:

[0223] (I) Preparation of ink layer materials, release layer materials and back coating materials:

[0224] 1. The raw material composition of the ink layer is the same as in Example 1;

[0225] 2. No, this comparative example does not include a release layer.

[0226] 3. Same as Example 1.

[0227] (II) Preparation of heat transfer ribbon:

[0228] 1. The back coating material described in this embodiment is coated onto a BOPET base film, and the UV irradiation dose is 50 mJ / cm. 2 The coating is cured into a film to obtain the back coating.

[0229] The thickness of the back coating is 1.5 ± 0.1 μm;

[0230] 2. The ink layer described in this embodiment is directly coated onto the BOPET base film, and cured into a film by UV irradiation at a dose of 90 mJ / cm2, with the coating thickness controlled at 1.6 ± 0.2 μm to obtain the ink layer.

[0231] 3. After being wound up into a master roll, and then divided into smaller rolls, the UV-curable heat transfer ribbon of this embodiment is obtained.

[0232] Comparative Example 8

[0233] Commercially available heat transfer ribbon, commercially available number B128, mixed base ribbon, Yigong Heat Transfer Ribbon (Shanghai) Co., Ltd.

[0234] Experimental Example 1

[0235] To demonstrate that the thermal transfer ribbons prepared in this application possess technical advantages such as low transfer temperature, high clarity in transfer and printing, and easy recognition of barcodes and fonts, the thermal transfer ribbons prepared in Examples 1-8 and Comparative Examples 1-7 were specifically tested.

[0236] 1. The Tg value of the example was measured using a differential scanning calorimeter, LX-DSC300.

[0237] 2. The results are obtained by printing with a barcode printer and then testing with a barcode quality detector.

[0238] Printing conditions: Barcode printer (Zebra 105SL Plus), speed 4 inches / second, energy level 12-16; media: plain coated paper or black coated label paper; (Avery Dennison)

[0239] Printable content: barcodes, patterns, and text.

[0240] Barcode rating detector: Shenzhen Matrix High Precision Technology Co., Ltd.

[0241] According to the international standard ISO / IEC 15416 barcode quality assessment method and criteria, four levels—A, B, C, and D—are used for evaluation, with A being the best and D the worst. Patterns and text are subjectively evaluated by personnel and compared with control sample tapes.

[0242] The specific test results are shown in the table below:

[0243]

[0244]

[0245] As can be seen from the results in the table above, the UV-cured heat transfer ribbons prepared in Examples 1 to 8 of this invention, after transfer printing, achieve the implementation target for barcode level detection, are feasible, have higher environmental protection in the production process, and have good development value.

[0246] Compared with Examples 1-8, Comparative Example 8 has different results due to the different ink materials and manufacturing processes, but Examples 1-8 have similar implementation effects to Comparative Example 8.

[0247] In Example 5, due to different material compositions and ratios, the Tg value was high. The use of red pigment in the superimposed pigment resulted in less contrast with the white label paper compared to black, leading to a lower barcode detection rating. In other words, the contrast of red pigment transferred onto a white label was not as good as that of black pigment transferred onto a white label. This can be further optimized by increasing the coating thickness.

[0248] Example 8: Due to different material composition and ratio, the Tg value is high. The pigment is made of silicon micro powder. Also, because it is printed on black coated label paper, the coverage is not as good as ordinary white label paper, resulting in discontinuous pattern. Later, it can be further optimized by increasing the coating thickness.

[0249] In Examples 1-8, due to different material compositions and ratios, the molecular weights after UV curing are different, resulting in differences in Tg values. Consequently, the heat transfer ribbons produced exhibit different transfer effects during use.

[0250] Compared with Examples 1-8, Comparative Example 1, due to the fact that the content of raw material components was not selected within the range of Examples 1-8 of this application, had a Tg value of 105°C after UV curing. When the heat transfer ribbon was used, the ink peeled off the PET substrate, the transferred image was unclear, the barcode level detector could not recognize it, and an error occurred.

[0251] Compared with Examples 1-8, Comparative Examples 2-4 were not selected within the range of Examples 1-8 of this application because the content of raw material components was not selected within the range of Examples 1-8. After UV curing, although the Tg value was close to the range of Examples 1-8, the uniformity of the heat transfer ribbon film was poor because the viscosity of the ink was too high, all greater than 850 mpa.s. Although the transferred barcode could be identified, the graphics and text were difficult to recognize.

[0252] Compared with Examples 1-8, Comparative Example 5, after UV curing, although the Tg value was within the range of Examples 1-8, had an extremely high viscosity due to the small abrasive particle size of the material, making it almost non-flowable with a viscosity greater than 2550 mpa.s. It could not be coated, could not be used to make heat transfer ribbons, and could not be compared.

[0253] Compared with Examples 1-8, Comparative Example 6, after UV curing, although the Tg value was within the range of Examples 1-8, had a large abrasive particle size and very low viscosity (less than 50 mPa·s). This made it easy for particles to be present during the coating process, resulting in missed coatings on the coating surface. The uniformity of the heat transfer ribbon film was poor, with random differences between segments (the first 200 meters were OK, the next 200 meters were NG, and the next 20 meters were OK). The transferred barcode could not be recognized, and the recognition of graphics and text was random, which did not meet the requirements.

[0254] Compared to Examples 1-8, Comparative Example 7 did not have a release layer. After UV curing, although the Tg value was within the range of Examples 1-8, the lack of a release layer resulted in excessive adhesion between the ink layer and the PET substrate after UV curing. This led to unclear images on the heat transfer ribbon, which the barcode grade detector could not recognize, resulting in errors.

[0255] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A UV-curable ink for heat transfer ribbons, characterized in that, The UV-curable ink comprises, by weight percentage: The composition includes 60-75% reactive oligomer monomers, 5-15% photoinitiator, 10-20% pigment, 0.5-8% additives, and 0.1-0.5% filler. The UV-curable ink has a Tg value of 65~80℃ after UV curing; The active oligomer monomer is one of monofunctional polyurethane acrylate, difunctional polyurethane acrylate, and trifunctional polyurethane acrylate. The additives include at least one of diluents, leveling agents, and dispersants; Wherein: the diluent includes at least one of ethoxylated trimethylolpropanetriol triacrylate, propoxylated trimethylolpropanetriol triacrylate, propoxylated glycerol triacrylate, 1,6-hexanediol methoxy monoacrylate, and ethoxylated neopentyl glycol methoxy monoacrylate. The leveling agent includes at least one of polyacrylate leveling agents, polymethylsiloxane leveling agents, and cellulose acetate butyrate. The dispersant includes at least one of polyalkylammonium salt copolymers, long-chain fatty acid dispersants, and acrylic copolymer dispersants.

2. The UV-curable ink for heat transfer ribbons according to claim 1, characterized in that, The UV-curable ink comprises, by weight percentage: The composition consists of 71% reactive oligomer monomers, 10% photoinitiator, 15% pigment, 3.9% additives, and 0.1% filler.

3. The UV-curable ink for heat transfer ribbons according to claim 1, characterized in that, The photoinitiator includes at least one of TPO-L photoinitiator, 907 photoinitiator, OMBB photoinitiator, 54 photoinitiator, and EDB photoinitiator.

4. The UV-curable ink for heat transfer ribbons according to claim 1, characterized in that, The pigment includes at least one of carbon black, pigment red, and pigment blue; The filler includes at least one of silicon dioxide, calcium carbonate, barium sulfate, and talc.

5. A method for preparing a UV-curable ink for heat transfer ribbons according to any one of claims 1 to 4, characterized in that, The preparation method includes: After mixing all the raw materials of the photoinitiator, disperse and grind them until the fineness of the pigment and filler is 0.2~2um. Then add the photoinitiator and mix well to obtain a UV-curable ink for heat transfer ribbon. The UV-curable ink coating thickness is 1.5~2µm, and the UV curing irradiation dose is 90mJ / cm. 2 .

6. A heat transfer ribbon, characterized in that, The heat transfer ribbon comprises, from bottom to top: a back coating layer, a substrate layer, a release layer, and an ink layer; The ink layer is prepared by UV curing of the UV-curable ink for heat transfer ribbons as described in any one of claims 1 to 4.

7. The heat transfer ribbon according to claim 6, characterized in that, The release layer is composed of wax and resin, wherein the mass ratio of wax to resin is 80~90:10~20, wherein: The wax includes at least one of palm wax, saxoline wax, candelilla wax, rice bran wax, fruit shell wax, lignite wax, Fischer-Tropsch wax, polyethylene wax, and polypropylene wax. The resin includes at least one of polyacrylic acid resin, EVA resin, polyurethane resin, phenolic resin, rosin resin, linear SBS, and linear SEBS.

8. The heat transfer ribbon according to claim 6, characterized in that, The substrate layer is a BOPET film with a thickness of 3.5~4.5um.

9. The heat transfer ribbon according to claim 6, characterized in that, The back coating is a UV-cured silicone back coating; The back coating thickness is 1~2µm, and the UV curing UV irradiation dose is 50mJ / cm. 2 .

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