High-efficiency laser thermal transfer ribbon with layered structure and preparation method and application thereof

Abstract

The application belongs to the technical field of laser thermal transfer printing, and particularly relates to a high-efficiency laser thermal transfer printing carbon ribbon with a layered structure and a preparation method and application thereof. The high-efficiency laser thermal transfer printing carbon ribbon with the layered structure comprises, in sequence, an ink layer, a transparent release layer, a black release layer and a transparent substrate. In the application, the combination of the black release layer, the transparent release layer and the ink layer forms an innovative layered structure, and the synergistic effect of the layers significantly improves the performance of the carbon ribbon.

Description

Technical Field

[0001] The present invention belongs to the technical field of laser thermal transfer, and in particular relates to a high-efficiency laser thermal transfer carbon ribbon with a layered structure, a preparation method thereof, and an application thereof. Background Art

[0002] In the existing thermal transfer technology, carbon ribbons have many problems, such as the transfer efficiency needs to be improved and the energy loss during the transfer process is large; the pattern quality is difficult to achieve the ideal state, and the line clarity, color saturation and resolution are limited; the adaptability to the substrate is insufficient, and the transfer effect on different material surfaces is uneven.

[0003] Laser thermal transfer is a printing technology that uses laser energy to cause a specific layer of a ribbon to absorb heat, causing the ink or dye layer to undergo a state change, thereby transferring the pattern to the substrate. Laser thermal transfer technology, due to its precision and efficiency, is widely used in packaging printing, label production, and personalized customization. However, as market demands for printing quality and efficiency continue to rise, traditional ribbons are no longer able to meet these demands. Specifically, existing ribbons have the following shortcomings:

[0004] Low transfer efficiency leads to longer production cycles and increased production costs, especially in large-scale printing tasks;

[0005] Poor pattern quality limits its application in high-end printing fields (such as art printing and high-resolution image printing), and cannot meet consumers' demand for exquisite printed products;

[0006] Poor adaptability of substrates requires frequent replacement or adjustment of carbon ribbons when used in different industries, which reduces production efficiency and increases operating costs.

[0007] However, in commercial printing (such as label and receipt printing), existing carbon ribbons may not be able to meet the needs of high-speed printing, and the printed patterns are prone to wear and fading; in personalized customized printing (such as customized gifts and decorative painting printing), it is difficult to achieve high color accuracy and rich color gradation printing effects; in industrial logo printing, the adhesion and corrosion resistance to substrates of different materials are insufficient.

[0008] Common methods to improve ribbon performance include:

[0009] 1. Improve the ink formula by adjusting the types and proportions of pigments, resins and additives to improve the color development and transferability of the ink, but this may cause ink stability and cost issues.

[0010] 2. Optimize the carbon ribbon substrate and select substrate materials with better quality or special properties, such as high-strength and high-flexibility substrates. However, the compatibility between the substrate and the coating and the overall performance balance face challenges.

[0011] 3. Adjust the laser parameters and optimize the laser wavelength, power, and pulse width according to the characteristics of the carbon ribbon. However, this requires precise equipment control and complex parameter debugging, and has limited adaptability to different carbon ribbons.

[0012] However, these common improvement methods have the following problems, which make it impossible to obtain high-efficiency laser thermal transfer ribbons:

[0013] 1. When optimizing the ink formula, the new ingredients may react chemically with other layers, affecting the overall performance of the ribbon. The increased cost may cause the product to lose price competitiveness. Moreover, it is impossible to fundamentally solve the problems of transfer efficiency and substrate adaptability.

[0014] 2. Although improving the substrate may improve some performance, it is difficult to take into account multiple requirements at the same time. For example, increasing strength may reduce flexibility and affect the performance of the carbon ribbon during bending or winding. Moreover, changes in the substrate may require re-optimization of the entire coating process, increasing technical difficulty and cost.

[0015] 3. Adjusting the laser parameters places high demands on the equipment. In actual production, the material properties of carbon ribbons in different batches may fluctuate to a certain extent, resulting in the pre-set laser parameters being unable to always maintain the best transfer effect, affecting production efficiency and product quality stability. Summary of the Invention

[0016] To address the shortcomings of existing technologies, the present invention provides a high-efficiency laser thermal transfer ribbon with a layered structure, as well as its preparation method and application. This invention significantly improves transfer efficiency, significantly enhances pattern quality, and enhances adaptability to a variety of substrates, while maintaining reasonable costs and meeting diverse printing needs.

[0017] The technical solutions provided by the present invention are as follows:

[0018] A high-efficiency laser thermal transfer carbon ribbon with a layered structure comprises an ink layer, a transparent release layer, a black release layer and a transparent substrate which are arranged in sequence.

[0019] In the above technical solution:

[0020] The black release layer can efficiently absorb laser energy and convert it into heat energy, providing sufficient heat for the transfer of the ink layer and ensuring that the ink layer can be smoothly separated from the black release layer after being heated to achieve transfer;

[0021] The transparent release layer has excellent transparency, flexibility, and adhesion, effectively isolating the black release layer from the ink layer, preventing the components of the ink layer from prematurely migrating to the black release layer. It also has good hardness, abrasion resistance, and thermal stability, providing excellent support for the ink layer and helping it remain intact during the transfer process. At the same time, the transparent release layer is fully transferred to the substrate along with the ink layer, protecting the ink while also preventing any color changes due to its transparent color.

[0022] The combination of black release layer, transparent release layer and ink layer forms an innovative layered structure, and the synergistic effect of each layer significantly improves the performance of the carbon ribbon.

[0023] substrate

[0024] Material selection: Select transparent polyethylene terephthalate film, polypropylene film, polyethylene naphthalate film, polyethylene film, polyvinyl alcohol film or polymethyl methacrylate film with a thickness of 4-10 microns. Polyethylene terephthalate (PET) film is preferably used as the supporting layer because it has good mechanical strength and can withstand various stresses during the preparation, storage, transportation and use of the carbon ribbon, and is not easy to break or deform; it has high chemical stability and can resist the erosion of ink, solvents and other chemicals, ensuring the stable performance of the carbon ribbon in different chemical environments; it has good dimensional stability and is not easy to expand and contract when the temperature and humidity change, ensuring the transfer accuracy; the surface flatness is high, which is conducive to the uniform coating of the primer layer and the ink layer.

[0025] Surface Treatment: The substrate surface is treated with corona treatment to achieve a dyne value of 42-50, enhancing adhesion to the photothermal conversion layer. The corona treatment lasts 5-10 seconds at a power of 1-3kW. The next coating step is performed immediately after treatment to prevent surface contamination that may affect adhesion.

[0026] Black release layer

[0027] Material composition and function: It is composed of carbon black (mass fraction 15%-25%), acrylic resin (mass fraction 65%-75%) and silicone release agent (mass fraction 5%-10%).

[0028] Based on the above technical solution:

[0029] Carbon black has excellent light absorption properties and can efficiently absorb laser energy and convert it into heat energy, providing sufficient heat for the transfer of the ink layer;

[0030] Acrylic resin acts as a binder to ensure the black release layer adheres firmly to the PET substrate while also providing good flexibility and heat resistance.

[0031] Silicone release agents reduce the adhesion between the black release layer and the ink layer, allowing the ink layer to smoothly separate from the black release layer after heating, achieving transfer printing;

[0032] The optimized combination of carbon black, acrylic resin and silicone release agent in the black release layer achieves efficient light-to-heat conversion and good release effect.

[0033] Preparation and coating process:

[0034] Carbon black is added to an organic solvent (such as toluene) containing an appropriate amount of a dispersant (such as sodium polyacrylate, with a mass fraction of 3%-5% of the carbon black mass). Ultrasonic dispersion equipment is used to disperse the mixture for 40-60 minutes at an ultrasonic power of 300-500W to form a uniform dispersion. Acrylic resin is then dissolved in the dispersion and stirred for 60-90 minutes. A silicone release agent is then added and stirred for a further 30-45 minutes to obtain a black release coating. Coating is performed using a gravure coater at a coating speed of 100-200 m / min, a drying temperature of 60-80°C, and a coating thickness of 0.3-0.8 μm.

[0035] Transparent release layer

[0036] Material composition and function: Polyvinyl butyral (PVB, mass fraction 80%-90%) and nano-silicon dioxide (mass fraction 10%-20%) are selected as the main components.

[0037] Based on the above technical solution:

[0038] PVB has good transparency, flexibility and adhesion, which can effectively isolate the black release layer and the ink layer, preventing the components in the ink layer from migrating to the black release layer prematurely;

[0039] Nano-silica can improve the hardness, wear resistance and thermal stability of the transparent release layer, while enhancing its support for the ink layer, helping the ink layer to remain intact during the transfer process;

[0040] The combination of PVB and nano-silica not only ensures the isolation and auxiliary demolding functions, but also enhances the overall performance.

[0041] Preparation and coating process: PVB is dissolved in a mixed solvent of ethanol and butanone (volume ratio of 1:1-2:1) to prepare a 10%-15% solution. Nanosilica is then added and stirred at 1500-2500 rpm for 30-60 minutes to form a transparent release coating. A micro-gravure coater is used for coating at a speed of 100-200 m / min and a drying temperature of 60-100°C. The thickness is controlled to 0.1-0.5 μm.

[0042] ink layer

[0043] Material selection and function: The ink is composed of thermoplastic polyester resin (mass fraction 40%-60%), pigment (such as carbon black, organic pigment, mass fraction 15%-30%), wax additives (such as microcrystalline wax, mass fraction 10%-20%) and organic solvent (such as methyl ethyl ketone, toluene, mass fraction 10%-20%).

[0044] Based on the above technical solution:

[0045] Thermoplastic polyester resin provides good adhesion and flexibility, allowing the ink to adhere firmly to the substrate;

[0046] Pigments ensure accurate color presentation and meet different printing color requirements;

[0047] Wax additives adjust the melting point and fluidity of the ink so that it can be transferred smoothly at an appropriate temperature during the transfer process; organic solvents facilitate the coating and drying of the ink, ensuring the uniformity of the ink layer.

[0048] Furthermore, additives may be added:

[0049] Add dispersants (such as high molecular weight polymer dispersants, with a mass fraction of 3%-6% of the pigment mass) to ensure uniform dispersion of the pigment in the ink and prevent pigment agglomeration from affecting printing quality;

[0050] Leveling agent (organic silicone leveling agent, mass fraction is 0.5%-1.5% of the total mass of ink) improves the surface flatness of the ink layer and reduces defects on the surface of the printed pattern;

[0051] The antioxidant (hindered phenol antioxidant, with a mass fraction of 0.5%-1% of the total mass of the ink) improves the anti-oxidation performance of the ink during storage and use, and extends the service life of the ink.

[0052] Coating parameters and thickness control: The ink layer is coated by gravure coating, the coating speed is 100-200m / min, the drying temperature is 70-100℃, and the thickness is controlled at 0.5-1.5μm according to printing requirements (such as the thickness of ordinary text and line printing can be 0.5-1.0μm, and the thickness of color image printing can be 1.0-1.5μm).

[0053] The present invention also provides a method for preparing a high-efficiency laser thermal transfer carbon ribbon with a layered structure, comprising the following steps: performing corona treatment on the surface of the substrate, and then sequentially preparing a black release layer, a transparent release layer, and an ink layer.

[0054] The present invention also provides an application of a high-efficiency laser thermal transfer carbon ribbon with a layered structure, which uses ultraviolet light, visible light or infrared light as a laser source for full transfer.

[0055] The beneficial effects of the present invention are as follows:

[0056] 1) In terms of transfer efficiency, by optimizing the light absorption and thermal conductivity of the black release layer and ensuring good coordination between the layers, the carbon ribbon transfer efficiency of the present invention is improved by 30%-60% compared to the existing technology, which can significantly shorten printing time and improve production efficiency;

[0057] 2) In terms of pattern quality, the uniform light-to-heat conversion of the black release layer, the stable support of the ink layer by the transparent release layer, and the precise control of laser energy by the protective layer make the line edges sharper and the pattern details clearly visible, with a clarity 25%-50% higher than that of existing technologies; the ink formula, the synergy between the layers, and the protection of the ink by the protective layer make the colors more vivid and lively, and the color saturation is 20%-30% higher than that of existing technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 The figure is a schematic structural diagram of the high-efficiency laser thermal transfer carbon ribbon with a layered structure provided by the present invention.

[0059] Figure 2 1 is a comparison chart of the printing effects of Example 1 and Comparative Example 1.

[0060] Attachment Figure 1 The structures represented by each number are listed as follows:

[0061] 1. Substrate; 2. Black release layer; 3. Transparent release layer; 4. Ink layer. DETAILED DESCRIPTION

[0062] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0063] Unless otherwise specified, the test methods used in the examples are conventional methods; the materials and reagents used are commercially available reagents and materials unless otherwise specified.

[0064] Carbon black can be selected from existing technologies, such as Cabot XP 190; sodium polyacrylate dispersant can be selected from existing technologies, such as Rohm & Haas NP-10;

[0065] Acrylic resin can be selected from existing technologies, such as BASF 43-30;

[0066] Silicone release agents can be selected from existing technologies, such as Shin-Etsu Chemical (Shin-Etsu) KF-960;

[0067] Polyvinyl butyral can be selected from existing technologies, such as DuPont B-79;

[0068] Nano silicon dioxide can be selected from existing technologies, such as Bayer ST 200;

[0069] Thermoplastic polyester resin can be selected from existing technologies, such as BASF 250;

[0070] Microcrystalline wax can be selected from existing technologies, such as Dow Corning 2-8566;

[0071] The high molecular weight polymer dispersant can be selected from existing technologies, such as Rohm & Haas NP-10;

[0072] The organic silicon leveling agent can be selected from existing technologies, such as Shin-Etsu Chemical (Shin-Etsu) KF-353S;

[0073] Hindered phenol antioxidants can be selected from existing technologies, such as BASF 1010;

[0074] Fluorocarbon resin modifiers can be selected from existing technologies, such as Hymen F 102.

[0075] In one embodiment, Figure 1 As shown, the high-efficiency laser thermal transfer carbon ribbon with a layered structure includes an ink layer 4, a transparent release layer 3, a black release layer 2 and a transparent substrate 1 arranged in sequence.

[0076] Example 1

[0077] PET substrate: 6μm PET film was selected for plasma treatment with a processing power of 200W and a processing time of 45 seconds.

[0078] Black release layer

[0079] 20 parts of carbon black, 0.8 parts of sodium polyacrylate dispersant, and 50 parts of toluene were ultrasonically dispersed for 50 minutes. 70 parts of acrylic resin was added and stirred for 75 minutes. 8 parts of silicone release agent was then added and stirred for 40 minutes to obtain the coating. The coating was applied using a gravure coater at a speed of 150 m / min and dried at 90°C to a thickness of 0.5 μm.

[0080] Transparent release layer

[0081] 85 parts of polyvinyl butyral (PVB) and 15 parts of nano-silica were dissolved in a mixed solvent of ethanol and butanone (1.5:1) and stirred at high speed for 50 minutes to prepare a coating. The coating was then applied using a gravure coater at a speed of 150 m / min and dried at 80°C to a thickness of 0.3 μm.

[0082] ink layer

[0083] 50 parts of thermoplastic polyester resin, 20 parts of carbon black pigment, 15 parts of microcrystalline wax, 10 parts of methyl ethyl ketone, 5 parts of toluene, 1.0 part of high molecular weight polymer dispersant, 1.0 part of silicone leveling agent, 0.8 part of hindered phenol antioxidant, after mixing, gravure coating at a speed of 150m / min, drying at 90℃, thickness of 1.0μm.

[0084] Example 2

[0085] PET substrate: same as in Example 1.

[0086] Black release layer: same as in Example 1.

[0087] Transparent release layer: the same as in Example 1.

[0088] ink layer

[0089] 45 parts of thermoplastic polyester resin, 25 parts of organic pigment (such as phthalocyanine blue), 18 parts of microcrystalline wax, 12 parts of methyl ethyl ketone, 8 parts of toluene, 1.2 parts of high molecular polymer dispersant, 1.2 parts of silicone leveling agent, 0.9 parts of hindered phenol antioxidant, after mixing, gravure coating at a speed of 150m / min, drying at 95℃, thickness of 1.2μm (for color image printing).

[0090] Example 3

[0091] PET substrate: same as in Example 1.

[0092] Black release layer: Add 10% fumed nano-silica (instead of the silicone release agent in the original solution).

[0093] Transparent release layer: add 5% fluorocarbon resin modifier.

[0094] Ink layer: UV curable ink system is used, and the preparation method is as follows: 45 parts of thermoplastic polyester resin, 25 parts of organic pigment, 18 parts of microcrystalline wax, 20 parts of toluene: butanone (1:1) mixed solvent, 1.2 parts of high molecular polymer dispersant, 1.2 parts of silicone leveling agent, 0.9 parts of hindered phenol antioxidant, after mixing, gravure coating, speed 150m / min, drying at 95℃, using 365nm ultraviolet wavelength light source for curing, thickness 1.2μm.

[0095] Tests show that the transfer efficiency is increased to 16.5±0.7cm 2 / s, weather resistance test passed ISO 105-B02 standard.

[0096] Comparative Example 1

[0097] Refer to Example 1, except that no carbon black is added to the release layer.

[0098] Comparative Example 2

[0099] Refer to Example 1, except that no transparent release layer is provided.

[0100] Comparative Example 3

[0101] Refer to Example 1, the difference is that the material of the black release layer is different, specifically, the acrylic resin is replaced by chloroacetic acid resin, the brand is Wacker H15 / 42.

[0102] Performance testing plan

[0103] 1. Transfer efficiency test

[0104] Test equipment and method: Using a high-precision timer and laser power meter, at a fixed laser wavelength (980nm) and power (8W), measure the time required for the carbon ribbon to transfer a specific pattern (such as a 10cm×10cm all-black pattern) on standard paper. The transfer efficiency is expressed in terms of the area transferred per unit time (cm 2 / s) to calculate.

[0105] Sample size and statistical analysis: Each example and comparative example was tested 5 times, the average value was taken as the final result, and the standard deviation was calculated to evaluate the dispersion of the data.

[0106] 2. Pattern quality test

[0107] Clarity Assessment

[0108] Test Equipment and Methods: Use a high-resolution optical microscope (500-1000x magnification) to observe the line edges of the transferred pattern and measure the line width deviation. Simultaneously, use professional image analysis software (such as ImageJ) to calculate pattern clarity parameters such as edge gradient and modulation transfer function (MTF).

[0109] Quantitative standards: line width deviation within ±5%, edge gradient value greater than 50, and MTF value greater than 0.4 at a specific frequency (such as 10lp / mm) are considered to have good clarity.

[0110] Color saturation evaluation

[0111] Test Equipment and Methods: Use a spectrophotometer (such as X-Rite i1Pro 2) to measure the color spectral reflectance of the transferred pattern, and calculate color saturation parameters (such as the range of a* and b coordinate values ​​and the C value) based on the color space (such as sRGB, Adobe RGB).

[0112] Quantification criteria: Color saturation is considered high when the a* and b coordinate values ​​are within a specific threshold (e.g., a is between -50 and 50, b is between -50 and 50) and the C value is greater than 50.

[0113] Line edge regularity assessment

[0114] Testing Equipment and Methods: Scanning electron microscopy (SEM) was used to observe the edge morphology of the transferred pattern and measure the edge roughness and irregularity. Image analysis software was also used to calculate the edge jaggedness parameters.

[0115] Quantitative standards: edge roughness less than 0.5μm and sawtooth parameter less than 0.1 are considered to be good line edge regularity.

[0116] Sample size and statistical analysis: Each example and comparative example was tested 5 times, the average value was taken as the final result, and the standard deviation was calculated to evaluate the reliability of the data.

[0117] 3. Substrate adaptability test

[0118] Testing of substrates of different materials: Paper (such as coated paper and thermal paper, coated paper is used uniformly in the test), plastic film (such as PET film and PP film, PET film is used uniformly in the test), leather and other substrates are selected for transfer testing under the same laser thermal transfer parameters.

[0119] Adhesion test method

[0120] Tape peel test: After transfer, apply standard tape (such as 3M tape) to the pattern surface. Roll the tape three times with a 2kg roller. Then, quickly peel the tape off at a 90° angle. Observe the pattern as it peels off and calculate the percentage of peeled area. A peeled area of ​​less than 5% is considered good adhesion.

[0121] Friction resistance test: Fix the transferred substrate on a friction tester. Use a rubber friction head to apply 5N pressure and rub it back and forth 100 times at a speed of 100mm / s. Observe the wear of the pattern and rate it according to the degree of wear (such as 1-5, 5 is no wear, and 1 is severe wear).

[0122] The test results are as follows:

[0123]

[0124] like Figure 2 The following is a comparison of the printing effects of Example 1 and Comparative Example 1. The left portion corresponds to Example 1, and the right portion corresponds to Comparative Example 1. Both are partial barcodes. It can be seen that Example 1 is superior to Comparative Example 1 in both clarity and edge regularity, indicating sufficient ink transfer.

[0125] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-efficiency laser thermal transfer ribbon with a layered structure, characterized by: It includes an ink layer, a transparent release layer, a black release layer and a transparent substrate arranged in sequence; The black release layer comprises the following components in the following mass percentages: carbon black 15%-25%, acrylic resin 65%-75%, silicone release agent or fumed nano-silica 5%-10%; The transparent release layer comprises the following components in mass percentage: polyvinyl butyral 80%-90%, nano silicon dioxide 10%-20%; Alternatively, the transparent release layer comprises the following components in the following mass percentages: 80%-90% polyvinyl butyral, 10%-20% nano-silicon dioxide, and 4%-6% fluorocarbon resin modifier.

2. The high-efficiency laser thermal transfer ribbon with a layered structure according to claim 1, characterized in that: The thickness of the black release layer is 0.3-0.8 μm.

3. The high-efficiency laser thermal transfer ribbon with a layered structure according to claim 1, characterized in that: The thickness of the transparent release layer is 0.1-0.5 μm.

4. The high-efficiency laser thermal transfer carbon ribbon with a layered structure according to claim 1, characterized in that: The ink layer is prepared from an ink coating liquid, which includes the following components in the following mass percentages: 40% to 60% thermoplastic polyester resin, 15% to 30% pigment, 10% to 20% wax additive, and 10% to 20% organic solvent. The thickness is 0.5 to 1.5 μm when used for text or line printing; or, the thickness is 1.0 to 1.5 μm when used for color image printing.

5. The high-efficiency laser thermal transfer ribbon with a layered structure according to claim 4, characterized in that: The pigment is carbon black or an organic pigment; The wax additive is microcrystalline wax; The organic solvent includes methyl ethyl ketone and toluene.

6. The high-efficiency laser thermal transfer carbon ribbon with a layered structure according to claim 4, characterized in that: The ink coating liquid may further comprise any one or more of the following additives: Dispersant, the amount of which is 3% - 6% of the pigment mass; Leveling agent, the amount is 0.5% - 1.5% of the mass of the ink coating liquid; The antioxidant is used in an amount of 0.5% to 1% by mass of the ink coating liquid.

7. The high-efficiency laser thermal transfer ribbon with a layered structure according to claim 6, characterized in that: The dispersant is a high molecular weight polymer dispersant; The leveling agent is an organic silicon leveling agent; The antioxidant is a hindered phenol antioxidant.

8. The high-efficiency laser thermal transfer carbon ribbon with a layered structure according to claim 1, characterized in that: The substrate is selected from a transparent polyethylene terephthalate film, a polypropylene film, a polyethylene naphthalate film, a polyethylene film, a polyvinyl alcohol film or a polymethyl methacrylate film; The thickness of the substrate is 4-10 μm.

9. A method for preparing a high-efficiency laser thermal transfer carbon ribbon with a layered structure according to any one of claims 1 to 8, characterized in that: The following steps are involved: The surface of the substrate is corona treated, and then a black release layer, a transparent release layer and an ink layer are prepared in sequence.

10. An application of the high-efficiency laser thermal transfer ribbon with a layered structure according to any one of claims 1 to 8, characterized in that: Ultraviolet light, visible light or infrared light is used as the laser source for full transfer.

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