Thermal dye sublimation ribbon suitable for soft label printing and preparation method of thermal dye sublimation ribbon

Abstract

The invention relates to a thermal dye sublimation ribbon suitable for soft label printing and a preparation method of the thermal dye sublimation ribbon. Comprising a base body and a back coating arranged on one side face of the base body, and further comprises a bottom coating and a dye layer which are sequentially arranged on the other side face of the base body. The bottom coating layer is mainly prepared from a bottom coating layer coating liquid, and the raw materials of the bottom coating layer coating liquid comprise bottom coating layer resin, an adhesion promoter and a first solvent; the prime coat resin accounts for 4%-10% of the prime coat coating liquid, and the adhesion promoter accounts for 10%-50% of the weight of the prime coat resin. According to the invention, the adhesion promoter is added into the bottom coating, so that the interlayer adhesion between the bottom coating and the dye layer as well as between the bottom coating and the base layer is improved, the dye release capacity during printing is enhanced, and the thermal sublimation imaging material has the characteristics of high adhesion and no influence on color saturation in the application of soft label printing.

Description

Technical Field

[0001] The invention relates to the field of thermal sublimation ribbons, and in particular to a thermal sublimation ribbon suitable for soft label printing and a preparation method thereof. Background Art

[0002] Thermal sublimation printing technology mainly uses heat energy to transfer the three dyes of yellow, magenta and cyan to the printing medium by sublimation. By controlling the temperature of the print head, different shades of color are obtained, and continuous color gradations are formed by superimposing the three colors. Its printing effect is more delicate than inkjet printing, and has higher color continuity and reduction than traditional printing through halftone printing of dot superposition. In addition, a thermal sublimation ribbon with excellent adhesion can be adapted to various photo papers with different viscosities on the market.

[0003] At present, there are wide applications of thermal sublimation ribbons on the market, such as soft labels, ID cards, photo printing and other fields, but there are three main problems in its actual application: (1) The base coat in the thermal sublimation ribbon mainly serves to improve the adhesion and dispersibility of the dye on the base layer, thereby improving the uniformity of the printed image and the vividness of the color; but in the high-speed printing process, the print head will form heat accumulation, causing the surface of the base paper to become sticky. If the adhesion of the base coat is not enough, there will be a risk of fading and falling off; (2) The dye layer is not sufficiently releasable, resulting in adhesion to the substrate during printing, resulting in falling off or other printing abnormalities; (3) The insufficient release ability of the dye leads to low color saturation of the printed color. In view of this, the present invention provides a thermal sublimation ribbon suitable for soft label printing and a preparation method thereof. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a thermal sublimation ribbon suitable for soft label printing and a preparation method thereof. The purpose is to reduce the risk of color fading in printing without affecting the color density of the ribbon by developing a primer layer with high adhesion, a dye layer with high dye release ability and a peeling layer that is easy to demold.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] In a first aspect, a thermal sublimation ribbon suitable for soft label printing comprises a substrate and a back coating layer arranged on one side of the substrate, and further comprises a primer layer and a dye layer arranged in sequence on the other side of the substrate;

[0007] The base coating is mainly made of a base coating liquid, the raw materials of which include a base coating resin, an adhesion promoter and a first solvent; the base coating resin accounts for 4%-10% of the base coating liquid, and the adhesion promoter accounts for 10%-50% of the base coating resin by weight.

[0008] The beneficial effects of the present invention are as follows: the present invention improves the interlayer adhesion between the base coat layer and the dye layer and the base layer by adding an adhesion promoter to the base coat layer, thereby enhancing the dye release ability during printing, and making the thermal sublimation imaging material have the characteristics of high adhesion without affecting the color saturation in the application of soft label printing.

[0009] Based on the above technical solution, the present invention can also be improved as follows.

[0010] Further, the base coating resin includes at least one of waterborne polyurethane, polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl acetal, polyvinyl butyral, and methyl cellulose;

[0011] The adhesion promoter includes at least one of a titanate coupling agent, an aluminate coupling agent, vinyl trimethoxy silane, acryl trimethoxy silane, acryl triamino methoxy silane and a phenolic resin;

[0012] The first solvent includes at least one of isopropanol, methanol, ethanol, n-butanol, n-propanol, ethylene glycol, propylene glycol, diethylene glycol, and propylene glycol methyl ether.

[0013] Furthermore, the dye layer is mainly made of a dye layer coating liquid, the raw materials of which include a dye layer resin, a dye, a first solid filler and a second solvent; the dye layer resin accounts for 2%-15% of the weight of the dye layer coating liquid, the weight ratio of the dye to the dye layer resin is 1-2.5:1, and the first solid filler accounts for 0.1%-5% of the weight of the dye layer resin.

[0014] Further, the dye layer resin includes at least one of polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl acetal, polyvinyl butyral, methyl cellulose, polyurethane, polycarbonate, polyester resin, polymethyl methacrylate, and pentaerythritol stearate;

[0015] The dye includes a yellow dye, a magenta dye or a cyan dye;

[0016] The first solid filler comprises at least one of calcium carbonate, kaolin, mica, silicon dioxide, diatomaceous earth, silica barium sulfate, calcium sulfate, polymethyl methacrylate, titanium dioxide, and carbon black;

[0017] The second solvent includes at least one of 2-butanone, toluene, xylene, ethyl acetate, butyl acetate, and propylene glycol methyl ether acetate.

[0018] Furthermore, it also includes a peeling layer, wherein the peeling layer is arranged on the dye layer;

[0019] The peeling layer is mainly made of a peeling layer coating liquid, the raw materials of which include a peeling layer resin, a second solid filler, a solid lubricant and a third solvent; the peeling layer resin accounts for 2%-15% of the weight of the peeling layer coating liquid, the second solid filler accounts for 1%-8% of the weight of the peeling layer resin, and the solid lubricant accounts for 0.1%-10% of the weight of the peeling layer resin.

[0020] The beneficial effect of adopting the above further solution is that the present invention has a good demoulding effect during the printing process by adding a peeling layer on the dye layer, thereby reducing the risk of discoloration.

[0021] Further, the peeling layer resin includes at least one of polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl acetal, polyvinyl butyral, methyl cellulose, polyurethane, polycarbonate, polyester resin, polymethyl methacrylate, and pentaerythritol stearate;

[0022] The second solid filler comprises at least one of calcium carbonate, kaolin, mica, silicon dioxide, diatomaceous earth, silica barium sulfate, calcium sulfate, polymethyl methacrylate, titanium dioxide, and carbon black;

[0023] The solid lubricant comprises at least one of graphite, graphite fluoride, polytetrafluoroethylene, molybdenum disulfide, tungsten disulfide, aluminum oxide, zirconium oxide, aluminum borate, polyimide, pentaerythritol stearate, polyparaben, vaseline, erucamide, and octadecyl erucamide;

[0024] The third solvent includes at least one of isopropanol, methanol, ethanol, n-butanol, n-propanol, ethylene glycol, propylene glycol, diethylene glycol, and propylene glycol methyl ether.

[0025] Furthermore, the material of the substrate includes any one of polypropylene (PP), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyethylene (PE), polyvinyl alcohol (PVA), and polymethyl methacrylate (PMMA); and the thickness of the substrate is 4 μm-130 μm.

[0026] Furthermore, the back coating layer is mainly made of a back coating layer coating liquid, and the raw materials of the back coating layer coating liquid include a back coating layer resin, an isocyanate compound, an inorganic filler, a release agent and a fourth solvent.

[0027] In a second aspect, a method for preparing a thermal sublimation ribbon suitable for soft label printing comprises the following steps:

[0028] (1) Preparation of solution:

[0029] Prepare a primer coating liquid, a dye layer coating liquid, a peeling layer coating liquid and a back coating liquid, wherein the dye layer coating liquid includes a yellow dye layer coating liquid, a magenta dye layer coating liquid and a cyan dye layer coating liquid for standby use;

[0030] (2) Electric shock;

[0031] Providing a substrate, and applying corona on two surfaces of the substrate;

[0032] (3) coating;

[0033] The back coating liquid in step (1) is coated on one surface of the substrate in step (2), and then dried to form a back coating for standby use;

[0034] The primer coating liquid, the yellow dye layer coating liquid, the magenta dye layer coating liquid, the cyan dye layer coating liquid and the peeling layer coating liquid in step (1) are sequentially coated on the other surface of the substrate, and dried to form a primer layer, a dye layer and a peeling layer, thereby obtaining a thermal sublimation ribbon suitable for soft label printing.

[0035] Furthermore, the back coating layer coating liquid, the bottom coating layer coating liquid, the yellow dye layer coating liquid, the magenta dye layer coating liquid, the cyan dye layer coating liquid and the peeling layer coating liquid are all coated by a gravure coater;

[0036] The thickness of the back coating liquid is 0.4μm-1.2μm, and the preferred thickness is 0.4μm-0.6μm; the thickness of the base coating liquid is 0.1μm-0.5μm, and the preferred thickness is 0.1μm-0.3μm; the thickness of the yellow dye layer coating liquid is 0.3μm-1.0μm; the thickness of the magenta dye layer coating liquid is 0.3μm-1.0μm; the thickness of the cyan dye layer coating liquid is 0.3μm-1.0μm; the thickness of the peeling layer coating liquid is 0.1μm-1.0μm. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of the layer structure of the thermal sublimation ribbon of the present invention.

[0038] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0039] 1- back coating layer, 2- base layer, 3- primer layer, 4- dye layer, 5- release layer. DETAILED DESCRIPTION

[0040] The principles and features of the present invention are described below, and the examples are only used to explain the present invention and are not used to limit the scope of the present invention. If no specific technology or conditions are specified in the embodiments, the technology or conditions described in the literature in this field or the product instructions are used. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased through regular channels.

[0041] This embodiment relates to a thermal sublimation ribbon suitable for soft label printing ( Figure 1 ), comprising a substrate and a back coating layer 1 disposed on one side of the substrate, and further comprising a primer layer 3 and a dye layer 4 disposed in sequence on the other side of the substrate;

[0042] The primer layer 3 is mainly made of a primer coating liquid, the raw materials of which include a primer resin, an adhesion promoter and a first solvent; the primer resin accounts for 4%-10% of the primer coating liquid, and the adhesion promoter accounts for 10%-50% of the weight of the primer resin.

[0043] The present invention improves the interlayer adhesion between the base coat 3, the dye layer 4 and the base layer 2 by adding an adhesion promoter into the base coat 3, thereby enhancing the dye release ability during printing; the thermal sublimation imaging material can have the characteristics of high adhesion without affecting the color saturation in the application of soft label printing.

[0044] The main function of the base layer 3 is to improve the adhesion and dispersibility of the dye on the base layer 2, thereby improving the uniformity and color vividness of the printed image. When heated during the printing process, the dye will diffuse in two opposite directions, the substrate and the adhesive layer, so the base layer 3 preferably selects a resin or sol that has poor dye adsorption and good adhesion to the base layer 2.

[0045] In this embodiment, the primer resin includes at least one of water-based polyurethane, polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl acetal, polyvinyl butyral, and methyl cellulose. The first solvent includes isopropyl alcohol. If the coating thickness is too low or too high, there is a risk of printing fading.

[0046] In order to further improve the adhesion of the primer layer 3, the dye layer 4 and the base layer 2, a better effect can be achieved by adding an appropriate amount of adhesion promoter. It can form a strong chemical bond at the interface between the ink layer and the base layer 2, and can also improve the surface wettability. In addition, it will also provide an intermediate modulus and effectively transfer stress between the base layer 2 and the ink layer. In this embodiment, the adhesion promoter includes at least one of a titanate coupling agent, an aluminate coupling agent, vinyl trimethoxy silane, acryl trimethoxy silane, acryl triamino methoxy silane, and a phenolic resin. More preferably, it is at least one of an aluminate coupling agent, a titanate coupling agent, and vinyl trimethoxy silane. During use, the adhesion promoter produces a cross-linking reaction with the base layer 2 and the ink binder, increasing the molecular weight and forming a cross-linking bridge. At the same time, it can also improve the rheological properties of the ink, generate affinity after chelation, enhance the adhesion between the ink and the substrate and the stability of the ink; it can also improve the surface gloss and film hardness of the ink, and accelerate the drying and curing speed of the ink; most importantly, the density of the coating will increase after the reaction, which can prevent the migration of the dye to the base coating 3 during application, thereby achieving the purpose of increasing the color density.

[0047] Preferably, in this embodiment, the dye layer 4 is mainly made of a dye layer coating liquid, and the raw materials of the dye layer coating liquid include a dye layer 4 resin, a dye, a first solid filler and a second solvent; the dye layer 4 resin accounts for 2%-15% of the weight of the dye layer coating liquid, the weight ratio of the dye to the dye layer 4 resin is 1-2.5:1, and the first solid filler accounts for 0.1%-5% of the weight of the dye layer 4 resin.

[0048] The function of the dye layer 4 is mainly to provide the dye in true color printing. There is no special restriction on this kind of dye, and it can be selected from a variety of sublimation dyes, preferably a dye with low melting and sublimation temperatures and good solubility. As a binder for the above-mentioned dye, the preferred embodiment of the present invention is that the resin of the dye layer 4 includes at least one of polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl acetal, polyvinyl butyral, methyl cellulose, polyurethane, polycarbonate, polyester resin, polymethyl methacrylate, and pentaerythritol stearate. Increasing the amount of resin added can increase the viscosity of the dye layer 4, thereby achieving better coating uniformity, but it will also hinder the sublimation of the dye during printing and reduce the printing color density; reducing the amount of resin added can increase the printing color density, but if the amount added is too low, there will be problems such as uneven coating film surface and easy migration of dye.

[0049] This ribbon is equipped with three dyes: yellow, magenta and cyan. The ratio of dye to resin in its formula can be adjusted according to the solubility of different color dyes and the color density required. Within a certain ratio range, when the total amount of resin and dye remains unchanged, increasing the proportion of dye and reducing the proportion of resin can greatly improve the color density of the ribbon. However, when the ratio of dye to resin reaches a certain value, the effect of improving color density gradually decreases.

[0050] In order to further ensure that the carbon ribbon can maintain good printing quality after being subjected to a high temperature and high humidity environment, and prevent the dye layer 4 from adhering to the back coating layer 1, a certain amount of a first solid filler can be added to the dye layer 4; preferably, in this embodiment, the first solid filler includes at least one of calcium carbonate, kaolin, mica, silicon dioxide, diatomaceous earth, silica barium sulfate, calcium sulfate, polymethyl methacrylate, titanium dioxide, and carbon black;

[0051] The second solvent includes 2-butanone and toluene.

[0052] The dye includes yellow dye, magenta dye or cyan dye; the recommended coating thickness of each layer in the dye layer 4 is 0.3μm-1.0μm. On the basis of achieving the required color density, the coating thickness of the dye layer 4 should be reduced as much as possible to obtain a better heat transfer effect, and at the same time, the utilization rate of the dye in the formula will be improved.

[0053] Preferably, the present embodiment further comprises a peeling layer 5, wherein the peeling layer 5 is arranged on the dye layer 4; the peeling layer 5 is mainly made of a peeling layer coating liquid, and the raw materials of the peeling layer coating liquid include a peeling layer resin, a second solid filler, a solid lubricant and a third solvent; the peeling layer resin accounts for 2%-15% of the weight of the peeling layer coating liquid, the second solid filler accounts for 1%-8% of the weight of the peeling layer resin, and the solid lubricant accounts for 0.1%-10% of the weight of the peeling layer resin.

[0054] The present invention adds a peeling layer 5 on the dye layer 4 to achieve a good demoulding effect during the printing process, thereby reducing the risk of discoloration.

[0055] The main function of the peeling layer 5 is to allow the ribbon to be demolded smoothly during printing, reducing the risk of color fading due to insufficient demolding of the dye layer 4. This layer needs to play a role in smooth demolding and should not affect the printing color density due to excessive thickness. The resin and filler type of the peeling layer 5 can be completely referred to the dye layer 4, and the second solid filler is preferably added in an amount of 1%-8% of the total resin.

[0056] In order to make the ribbon adapt to the high heat and high pressure required for printing, reduce the transfer of liquid lubricant on the substrate to the ribbon, and avoid the situation that the ribbon and the substrate are bonded during printing, the smoothness of the peeling layer 5 needs to be increased. A certain amount of solid lubricant can be added to the peeling layer 5 to improve the smoothness of the ribbon surface. Considering that the dye layer 4 will be in direct contact with the back coating layer 1 when the ribbon is rolled up, in order to make the ribbon still maintain good printing quality after passing through a high temperature and high humidity environment, a solid lubricant with a higher melting point is preferably used to reduce the migration of the dye and lubricant to the back coating layer 1. In this embodiment, the peeling layer resin preferably includes at least one of polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl acetal, polyvinyl butyral, methyl cellulose, polyurethane, polycarbonate, polyester resin, polymethyl methacrylate, and pentaerythritol stearate. In particular, when printing at low color levels, since the resin of the dye layer 4 is not completely melted, a lubricant in a molten state is required to assist the migration of the dye to the surface of the substrate. At the same time, the lubricant needs to remain in a solid state in a high temperature and high humidity environment to prevent dye migration. Therefore, the lubricant is preferably at least one of pentaerythritol stearate, octadecyl erucamide, and erucamide with a melting point of about 60-70°C. This can provide smoothness and reduce dye migration while having a certain effect of improving the color density of the low color levels of the ribbon.

[0057] In this embodiment, the material of the substrate includes any one of polypropylene (PP), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyethylene (PE), polyvinyl alcohol (PVA), and polymethyl methacrylate (PMMA); PET is preferred. The thickness of the substrate is 4μm-130μm, and the preferred substrate thickness is 4.3μm-13μm; generally speaking, surface treatment of the substrate is a common process before coating, and a simple and efficient method is often to use corona treatment, so that the dyne value of the substrate surface is greater than 38, which meets the requirements.

[0058] Preferably, in this embodiment, the back coating layer 1 is mainly made of a back coating layer coating liquid, and the raw materials of the back coating layer coating liquid include a back coating layer 1 resin, an isocyanate compound, an inorganic filler, a release agent and a fourth solvent.

[0059] The effect of the back coating 1 is to provide smoothness under different printing temperatures, avoid the adverse effects such as lateral wrinkles or stickiness in printing, and clean and protect the print head and ensure the uniform transfer of heat so that the glossiness of the front layer after transfer is improved, the surface roughness decreases, and the wear resistance of the protective layer is improved. The back coating 1 component is suitably selected to form with existing known thermoplastic resins. As such thermoplastic resins, for example, polyester resins, polyacrylate resins, polyvinyl acetate resins, styrene acrylate resins, polyurethane resins, polyethylene resins, polypropylene resins and other polyolefin resins, polystyrene resins, polyvinyl chloride resins, polyether resins, polyamide resins, polyimide resins, polyamide-imide resins, polycarbonate resins, polyacrylamide resins, polyvinyl chloride resins, polyvinyl butyral resins, polyvinyl acetal resins and other thermoplastic resins such as polyvinyl acetal resins, their silicone modified products, etc. Preferred polyvinyl butyral resins.

[0060] To improve the heat resistance of the back coating 1 during printing, improve the adhesion of the back coating 1 to PET and reduce the viscosity at high temperature. Isocyanate compounds can be added to the above-mentioned resin. There is no particular restriction on the type of isocyanate compounds. Existing well-known substances can be used, such as toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate (HMDI), hexamethylene diisocyanate (HDI), lysine diisocyanate (LDI), etc. It is preferred to use aromatic isocyanate compounds. As aromatic isocyanate compounds, for example, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, di-toluidine diisocyanate, p-phenylene diisocyanate, etc. can be cited. The amount used is 0.1%-2% of the total amount.

[0061] In order to keep the carbon ribbon having excellent smoothness during high-speed printing, inorganic fillers such as talcum powder, kaolin, calcium carbonate, aluminum hydroxide, silicon dioxide, graphite, boron nitride, and mold release agents such as phosphate compounds, metal soaps, silicone oil, and surfactants need to be added to the back coating 1. Preferably, the inorganic filler is talcum powder, the mesh number of the talcum powder is 5000-11000, and the addition amount is 1%-5% of the weight of the resin, preferably 3%-5%. Preferably, the mold release agent is phosphate ester, and the addition amount is 1%-10% of the weight of the resin, preferably 3%-5%.

[0062] In order to ensure that the inorganic filler is evenly dispersed in the resin, improve the thermal conductivity of the back coating, increase the gloss after transfer, reduce the surface roughness, and improve the wear resistance, it is necessary to control the overall particle size and particle size distribution of the back coating 1 filler. The filler D50 particle size is required to be 1.0um-5um, and the D90 particle size is 3um-10um. If the requirements cannot be met, grinding treatment is required.

[0063] The preparation method of the back coating layer 1 is to dissolve a certain amount of resin in a conventional organic solvent. There is no particular limitation on the type of conventional organic solvent, as long as the resin can be dissolved in an appropriate organic solvent and the viscosity at 25°C is within 100-500mPa·s. For example, the organic solvent can be selected from acetone, 2-butanone, cyclohexanone, isophorone, tetrahydrofuran, ethyl acetate, butyl acetate, propyl acetate, toluene, xylene, DMF, etc., preferably 2-butanone and toluene are miscible, and the ratio of 2-butanone to toluene is controlled between 8:2-1:1, and the content is preferably 50%-80% of the total mass of the back coating layer 1. Then, a certain amount of auxiliary agent is added to obtain a back coating liquid, and the back coating liquid is coated on the surface of the base layer 2 by gravure coating or slit coating and dried, the drying temperature is 60°C-120°C, and the drying time is 60s-120s. The coating thickness of the back coating layer 1 is generally 0.4μm-1.2μm, preferably 0.4μm-0.6μm.

[0064] This embodiment also relates to a method for preparing a thermal sublimation ribbon suitable for soft label printing, comprising the following steps:

[0065] (1) Preparation of solution:

[0066] Prepare a primer coating liquid, a dye layer coating liquid, a peeling layer coating liquid and a back coating liquid, wherein the dye layer coating liquid includes a yellow dye layer coating liquid, a magenta dye layer coating liquid and a cyan dye layer coating liquid for standby use;

[0067] (2) Electric shock;

[0068] Providing a substrate, and applying corona on two surfaces of the substrate;

[0069] (3) coating;

[0070] The back coating liquid in step (1) is coated on one surface of the substrate in step (2), and then dried to form a back coating layer 1 for standby use;

[0071] The primer coating liquid, the yellow dye layer coating liquid, the magenta dye layer coating liquid, the cyan dye layer coating liquid and the peeling layer coating liquid in step (1) are sequentially coated on the other surface of the substrate, and dried to form a primer layer 3, a dye layer 4 and a peeling layer 5, thereby obtaining a thermal sublimation ribbon suitable for soft label printing.

[0072] In this embodiment, the back coating layer coating liquid, the base coating layer coating liquid, the yellow dye layer coating liquid, the magenta dye layer coating liquid, the cyan dye layer coating liquid and the peeling layer coating liquid are all coated by a gravure coater;

[0073] The thickness of the back coating liquid is 0.4μm-1.2μm, and the preferred thickness is 0.4μm-0.6μm; the thickness of the base coating liquid is 0.1μm-0.5μm, and the preferred thickness is 0.1μm-0.3μm; the thickness of the yellow dye layer coating liquid is 0.3μm-1.0μm; the thickness of the magenta dye layer coating liquid is 0.3μm-1.0μm; the thickness of the cyan dye layer coating liquid is 0.3μm-1.0μm; the thickness of the peeling layer coating liquid is 0.1μm-1.0μm.

[0074] The following is described with specific embodiments:

[0075] Embodiment 1:

[0076] This embodiment relates to a thermal sublimation ribbon suitable for soft label printing, comprising a substrate and a back coating layer 1 arranged on one side of the substrate, and further comprising a primer layer 3 and a dye layer 4 arranged in sequence on the other side of the substrate;

[0077] ① The base layer 2 uses a 4.5 μm PET film (Lumirror Japan Toray).

[0078] ② The primer coating liquid includes the following raw materials by weight: 3 parts of polyvinyl pyrrolidone (industrial grade PVP K90 Guangdong Yuemei Chemical), 3 parts of polyvinyl alcohol (Tianjin Damao Chemical), and 94 parts of isopropanol. It is coated using a gravure coater with a coating thickness of 0.36 μm.

[0079] ③ Dye layer coating liquid;

[0080] The yellow dye layer coating liquid includes the following raw materials by weight: 2.75 parts of polyurethane (901H Wanhua Chemical), 3.98 parts of solvent yellow 2 (Henan Wokas Biotechnology), 0.03 parts of polymethyl methacrylate (CM 205 Chimei, Taiwan, China), 46.62 parts of 2-butanone, and 46.62 parts of toluene. It is coated using a gravure coater with a coating thickness of 0.4 μm.

[0081] The magenta dye layer coating liquid includes the following raw materials by weight: 2.86 parts of polyurethane (901H Wanhua Chemical), 5.27 parts of Solvent Red 24 (Sinopharm Chemical Reagent), 0.03 parts of polymethyl methacrylate (CM 205 Chimei, Taiwan, China), 45.92 parts of 2-butanone, and 45.92 parts of toluene. It is coated using a gravure coater with a coating thickness of 0.6 μm.

[0082] The cyan dye layer coating liquid includes the following raw materials by weight: 2.67 parts of polyurethane (901H Wanhua Chemical), 5.46 parts of solvent blue 36 (Nanjing Kangmanlin Chemical Industry), 0.03 parts of polymethyl methacrylate (CM 205 Chimei, Taiwan, China), 45.93 parts of 2-butanone, and 45.93 parts of toluene. It is coated using a gravure coater with a coating thickness of 0.8 μm.

[0083] ④ The back coating coating liquid includes the following raw materials by weight: 3 parts of polyvinyl butyral (B265H-B Guangzhou Hongshang), 7 parts of cellulose acetate butyrate (CAB393-3 American Eastman), 7 parts of isocyanate ( MDI-50 Wanhua Chemical) 2.5 parts, talcum powder (LJ-320 Liangjiang Chemical) 0.5 parts, silicone oil (KF-6001 Shin-Etsu Silicone) 0.2 parts, 2-butanone 57.8 parts, toluene 29 parts, use a gravure coater to coat, the coating thickness is 0.5μm.

[0084] Embodiment 2:

[0085] The base layer 2, dye layer 4 and back coating layer 1 of this embodiment are consistent with those of Example 1; the primer coating liquid includes the following raw materials by weight: 2.61 parts of polyvinyl pyrrolidone (industrial grade PVP K90 Guangdong Yuemei Chemical), 2.61 parts of polyvinyl alcohol (Tianjin Damao Chemical), 0.78 parts of titanate coupling agent (Shanghai Lanthanum Chemical), 94 parts of isopropanol, and is coated using a gravure coater with a coating thickness of 0.36 μm.

[0086] Embodiment 3:

[0087] The base layer 2, dye layer 4 and back coating layer 1 of this embodiment are consistent with those of Example 1; the primer coating liquid includes the following raw materials by weight: 1.5 parts of polyvinyl pyrrolidone (industrial grade PVP K90 Guangdong Yuemei Chemical), 1.5 parts of polyvinyl alcohol (Tianjin Damao Chemical), 3 parts of water-based polyurethane (R-1007 BASF, Germany), 94 parts of isopropanol, and is coated using a gravure coater with a coating thickness of 0.36 μm.

[0088] Embodiment 4:

[0089] The base layer 2, the primer layer 3, the back coating layer 1, and the dye layer 4 of this embodiment are the same as those of embodiment 2. A peeling layer 5 is added, and the peeling layer coating liquid includes the following raw materials by weight: 1.808 parts of polyurethane (901H Wanhua Chemical), 0.096 parts of polymethyl methacrylate (CM 205 Chimei, Taiwan, China), 0.096 parts of pentaerythritol stearate (PETS Lonza, USA), 98 parts of isopropyl alcohol, and the coating is applied using a gravure coater with a coating thickness of 0.1 μm.

[0090] Comparative Example 1: No primer layer 3.

[0091] The base layer 2, dye layer 4 and back coating layer 1 of this embodiment are consistent with those of Embodiment 1, but there is no primer layer 3.

[0092] Comparative Example 2: The solid content of the primer layer 3 is reduced.

[0093] The base layer 2, dye layer 4 and back coating layer 1 of this embodiment are consistent with those of embodiment 1. The base coating liquid includes the following raw materials by weight: 2 parts of polyvinyl pyrrolidone (industrial grade PVP K90 Guangdong Yuemei Chemical),

[0094] 2 parts of polyvinyl alcohol (Tianjin Damao Chemical) and 96 parts of isopropyl alcohol were coated using a gravure coater with a coating thickness of 0.2 μm.

[0095] Comparative Example 3: The solid content of the primer layer 3 was reduced and titanate was added.

[0096] The base layer 2, dye layer 4 and back coating layer 1 of this embodiment are consistent with those of embodiment 1. The coating solution of the base layer includes the following raw materials by weight: 1.74 parts of polyvinyl pyrrolidone (industrial grade PVP K90 Guangdong Yuemei Chemical), 1.74 parts of polyvinyl alcohol (Tianjin Damao Chemical),

[0097] 0.52 parts of titanate coupling agent (Shanghai Lanthanum Chemical) and 96 parts of isopropyl alcohol were coated using a gravure coater with a coating thickness of 0.2 μm.

[0098] Comparative Example 4: The solid content of the original primer layer 3 was reduced, and the amount of titanate added was reduced.

[0099] The base layer 2, dye layer 4 and back coating layer 1 of this embodiment are consistent with those of Example 1. The primer coating liquid includes the following raw materials by weight: 1.74 parts of polyvinyl pyrrolidone (industrial grade PVP K90 Guangdong Yuemei Chemical), 1.74 parts of polyvinyl alcohol (Tianjin Damao Chemical), 0.52 parts of titanate coupling agent (Shanghai Lanthanum Chemical), and 96 parts of isopropanol. The coating is applied using a gravure coater with a coating thickness of 0.36 μm.

[0100] Comparative Example 5: The solid content of the original primer coating 3 and the proportion of waterborne polyurethane were reduced.

[0101] The base layer 2, dye layer 4 and back coating layer 1 of this embodiment are consistent with those of Example 1. The primer coating liquid includes the following raw materials by weight: 2 parts of polyvinyl pyrrolidone (industrial grade PVP K90 Guangdong Yuemei Chemical), 2 parts of polyvinyl alcohol (Tianjin Damao Chemical), 2 parts of water-based polyurethane (R-1007 BASF, Germany), 94 parts of isopropanol, and is coated using a gravure coater with a coating thickness of 0.36 μm.

[0102] Comparative Example 6: The solid content of the peeling layer 5 is reduced.

[0103] The base layer 2, the primer layer 3, the back coating layer 1, and the dye layer 4 of this embodiment are the same as those of embodiment 1. A peeling layer 5 is added, and the peeling layer coating liquid includes the following raw materials by weight: 0.904 parts of polyurethane (901H Wanhua Chemical), 0.048 parts of polymethyl methacrylate (CM 205 Chimei, Taiwan, China), 0.048 parts of pentaerythritol stearate (PETS Lonza, USA), 99 parts of isopropyl alcohol, and the coating is applied using a gravure coater with a coating thickness of 0.1 μm.

[0104] Comparative Example 7: Improving the solid content of the peeling layer 5.

[0105] The base layer 2, the primer layer 3, the back coating layer 1, and the dye layer 4 of this embodiment are the same as those of embodiment 1. A peeling layer 5 is added, and the peeling layer coating liquid includes the following raw materials by weight: 2.712 parts of polyurethane (901H Wanhua Chemical), 0.144 parts of polymethyl methacrylate (CM 205 Chimei, Taiwan, China), 0.144 parts of pentaerythritol stearate (PETS Lonza, USA), 97 parts of isopropyl alcohol, and the coating is applied using a gravure coater with a coating thickness of 0.2 μm.

[0106] Comparative Example 8: The solid lubricant is removed from the peeling layer 5.

[0107] The base layer 2, the primer layer 3, the back coating layer 1, and the dye layer 4 of this embodiment are the same as those of embodiment 1. A peeling layer 5 is added, and the peeling layer coating liquid includes the following raw materials by weight: 1.9 parts of polyurethane (901H Wanhua Chemical), 0.1 parts of polymethyl methacrylate (CM 205 Chimei, Taiwan, China), and 98 parts of isopropyl alcohol, and the coating is applied using a gravure coater with a coating thickness of 0.1 μm.

[0108] Test example:

[0109] (1) Color fading test

[0110] Color fading test: Use DTP330 to print complex dark-tone images, and set the STB values ​​to Y185, M200, C200, and OC100. Carefully observe the color fading on the surface of the image. √ means no color fading, □ means there is a risk of color fading, and × means color fading.

[0111] (2) Color density test

[0112] Color density test: Use DTP330 for printing, and set STB values ​​to Y185, M200, C200, and OC100. Use X-Rite i1 PRO3 colorimeter to test the color density of the 16-color scale chart of the printed product with OC, and select the highest and lowest color scale data for recording.

[0113] The evaluation results are as follows:

[0114] The highest color level is Y≥1.6, M≥1.75, C≥1.8, set to A;

[0115] The highest color level is 1.5≤Y<1.6, 1.65≤M<1.75, 1.7≤C<1.8, set to B;

[0116] The highest color level is 1.4≤Y<1.5, 1.55≤M<1.65, 1.6≤C<1.7, set to C;

[0117] The highest color level is Y<1.4, M<1.55, C<1.6, set to D;

[0118] The lowest color level 0.05≤Y / M / C<0.1 is set as A;

[0119] The lowest color level Y / M / C<0.05, set to B.

[0120] Table 1 The test results are as follows

[0121]

[0122]

[0123] In summary, the present invention improves the interlayer adhesion between the base coat 3, the dye layer 4 and the substrate by adding an adhesion promoter to the base coat 3. This method may reduce the dye release ability during printing; the adhesion is improved by appropriately increasing the coating thickness of the base coat 3, but this solution still has the risk of discoloration, and thickening the base coat 3 will lead to a decrease in heat transfer efficiency, resulting in the color saturation of the ribbon printing not meeting the requirements; by adding a peeling layer 5 on the dye layer 4, a good demoulding effect is achieved during the printing process, thereby reducing the risk of discoloration.

[0124] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A thermal sublimation ribbon suitable for soft label printing, comprising a substrate and a back coating arranged on one side of the substrate, characterized in that: It also includes a primer layer and a dye layer sequentially disposed on the other side of the substrate; The base coating is mainly made of a base coating liquid, the raw materials of which include a base coating resin, an adhesion promoter and a first solvent; the base coating resin accounts for 4%-10% of the base coating liquid, and the adhesion promoter accounts for 10%-50% of the base coating resin by weight.

2. According to claim 1, a thermal sublimation ribbon suitable for soft label printing, characterized in that: The base coating resin includes at least one of waterborne polyurethane, polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl acetal, polyvinyl butyral, and methyl cellulose; The adhesion promoter includes at least one of a titanate coupling agent, an aluminate coupling agent, vinyl trimethoxy silane, acryl trimethoxy silane, acryl triamino methoxy silane and a phenolic resin; The first solvent includes at least one of isopropanol, methanol, ethanol, n-butanol, n-propanol, ethylene glycol, propylene glycol, diethylene glycol, and propylene glycol methyl ether.

3. According to claim 1, a thermal sublimation ribbon suitable for soft label printing is characterized in that: The dye layer is mainly made of a dye layer coating liquid, the raw materials of which include a dye layer resin, a dye, a first solid filler and a second solvent; the dye layer resin accounts for 2%-15% of the weight of the dye layer coating liquid, the weight ratio of the dye to the dye layer resin is 1-2.5:1, and the first solid filler accounts for 0.1%-5% of the weight of the dye layer resin.

4. According to claim 3, a thermal sublimation ribbon suitable for soft label printing is characterized in that: The dye layer resin includes at least one of polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl acetal, polyvinyl butyral, methyl cellulose, polyurethane, polycarbonate, polyester resin, polymethyl methacrylate, and pentaerythritol stearate; The dye includes a yellow dye, a magenta dye or a cyan dye; The first solid filler comprises at least one of calcium carbonate, kaolin, mica, silicon dioxide, diatomaceous earth, silica barium sulfate, calcium sulfate, polymethyl methacrylate, titanium dioxide, and carbon black; The second solvent includes at least one of 2-butanone, toluene, xylene, ethyl acetate, butyl acetate, and propylene glycol methyl ether acetate.

5. The thermal sublimation ribbon suitable for soft label printing according to claim 1, characterized in that: Also included is a peeling layer, the peeling layer being disposed on the dye layer; The peeling layer is mainly made of a peeling layer coating liquid, the raw materials of which include a peeling layer resin, a second solid filler, a solid lubricant and a third solvent; the peeling layer resin accounts for 2%-15% of the weight of the peeling layer coating liquid, the second solid filler accounts for 1%-8% of the weight of the peeling layer resin, and the solid lubricant accounts for 0.1%-10% of the weight of the peeling layer resin.

6. The thermal sublimation ribbon suitable for soft label printing according to claim 5, characterized in that: The peeling layer resin includes at least one of polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl acetal, polyvinyl butyral, methyl cellulose, polyurethane, polycarbonate, polyester resin, polymethyl methacrylate, and pentaerythritol stearate; The second solid filler comprises at least one of calcium carbonate, kaolin, mica, silicon dioxide, diatomaceous earth, silica barium sulfate, calcium sulfate, polymethyl methacrylate, titanium dioxide, and carbon black; The solid lubricant comprises at least one of graphite, graphite fluoride, polytetrafluoroethylene, molybdenum disulfide, tungsten disulfide, aluminum oxide, zirconium oxide, aluminum borate, polyimide, pentaerythritol stearate, polyparaben, vaseline, erucamide, and octadecyl erucamide; The third solvent includes at least one of isopropanol, methanol, ethanol, n-butanol, n-propanol, ethylene glycol, propylene glycol, diethylene glycol, and propylene glycol methyl ether.

7. A thermal sublimation ribbon suitable for soft label printing according to any one of claims 1 to 6, characterized in that: The material of the substrate includes any one of polypropylene, polyethylene naphthalate, polyethylene terephthalate, polyethylene, polyvinyl alcohol, and polymethyl methacrylate; the thickness of the substrate is 4 μm-130 μm.

8. A thermal sublimation ribbon suitable for soft label printing according to any one of claims 1 to 6, characterized in that: The back coating layer is mainly made of a back coating layer coating liquid, and the raw materials of the back coating layer coating liquid include a back coating layer resin, an isocyanate compound, an inorganic filler, a release agent and a fourth solvent.

9. A method for preparing a thermal sublimation ribbon suitable for soft label printing according to any one of claims 1 to 8, characterized in that: The steps include: (1) Preparation of solution: Prepare a primer coating liquid, a dye layer coating liquid, a peeling layer coating liquid and a back coating liquid, wherein the dye layer coating liquid includes a yellow dye layer coating liquid, a magenta dye layer coating liquid and a cyan dye layer coating liquid for standby use; (2) Electric shock; Providing a substrate, and applying corona on two surfaces of the substrate; (3) coating; The back coating liquid in step (1) is coated on one surface of the substrate in step (2), and then dried to form a back coating for standby use; The primer coating liquid, the yellow dye layer coating liquid, the magenta dye layer coating liquid, the cyan dye layer coating liquid and the peeling layer coating liquid in step (1) are sequentially coated on the other surface of the substrate, and dried to form a primer layer, a dye layer and a peeling layer, thereby obtaining a thermal sublimation ribbon suitable for soft label printing.

10. A method for preparing a thermal sublimation ribbon suitable for soft label printing according to claim 9, characterized in that: The back coating layer coating liquid, the base coating layer coating liquid, the yellow dye layer coating liquid, the magenta dye layer coating liquid, the cyan dye layer coating liquid and the peeling layer coating liquid are all coated by a gravure coater; The thickness of the back coating liquid is 0.4μm-1.2μm; the thickness of the base coating liquid is 0.1μm-0.5μm; the thickness of the yellow dye layer coating liquid is 0.3μm-1.0μm; the thickness of the magenta dye layer coating liquid is 0.3μm-1.0μm; the thickness of the cyan dye layer coating liquid is 0.3μm-1.0μm; the thickness of the peeling layer coating liquid is 0.1μm-1.0μm.

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