High-temperature-resistant digital printing ink as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of printing ink, and particularly relates to high-temperature-resistant digital printing ink as well as a preparation method and application thereof. The high-temperature-resistant digital printing ink is prepared from the following raw materials in parts by mass: 10 to 25 parts of dye, 1 to 5 parts of nano silicon dioxide, 0.5 to 1.5 parts of cuprous iodide, 1 to 3.5 parts of potassium iodide, 1 to 10 parts of nano titanium dioxide, 1 to 5 parts of a bio-based brightening agent, 1.0 to 2.5 parts of a color fixing agent, 40 to 60 parts of water, 15 to 25 parts of a cosolvent, 0.5 to 1.5 parts of a pH regulator, 0.1 to 0.5 part of an antibacterial agent and 0.1 to 0.5 part of a de-foaming agent. The nano silicon dioxide, the cuprous iodide and the potassium iodide cooperate to protect dye molecules through a chemical effect, the nano titanium dioxide and the bio-based brightening agent cooperate to act on the dye molecules and the fibers, and the color fixing agent acts on the dye-fibers; the three components act together to improve the high temperature resistance, bright color and washing resistance of the printing ink.

Description

Technical Field

[0001] This invention relates to the field of digital printing technology, and in particular to a high-temperature resistant digital printing ink, its preparation method, and its application. Background Technology

[0002] The current carpet market reflects the growing pursuit of home décor and comfort. As people's living standards improve, their demands for home environments also increase. As an important home decoration, carpets have become a key focus for consumers in terms of aesthetics, comfort, and practicality. Digitally printed carpets are carpet products made using modern digital printing technology. This technology allows designers to create complex patterns on a computer and print them directly onto carpet materials, resulting in carpets with unique patterns and colors. Digitally printed carpets not only have a beautiful appearance but also excellent durability and easy cleaning, making them an ideal choice for modern home décor.

[0003] Digital heat transfer is a process that transfers patterns onto various substrates through heat pressing. During this process, the ink bonds with the substrate under heat and pressure. This necessitates ensuring the heat resistance of the ink used for printing. Generally, modified resins are used, but the addition of resin can lead to insufficient ink flow and poor stability. Patent document CN119859240A mentions a water-based polyurethane resin and its preparation method for heat transfer ink. This preparation method uses modified polyurethane resin, improving the issues of insufficient flow and poor stability caused by added resin. However, it is not easy to preserve for long periods, and the preparation process is difficult and complex.

[0004] Digital heat transfer ink is a special ink used for digital heat transfer printing. In the printing process, the printed pattern needs to be printed on a transfer film first, and then the printed pattern on the transfer film is heat-transferred onto the substrate. However, many existing digital heat transfer inks have the disadvantages of insufficient smoothness and poor stability. Furthermore, when applied to polyester-cotton fiber textiles, their poor adhesion to the fibers results in insufficient adhesion and water resistance of the heat transfer pattern. Summary of the Invention

[0005] One objective of this invention is to provide a novel ink specifically for high-temperature heat transfer printing technology, prepared using dyes, nano-silica, high-temperature resistant additives, nano-titanium dioxide, bio-based brighteners, color-fixing agents, and water, to address the issue of unclear and saturated patterns in carpet printing during high-temperature heat transfer printing processes.

[0006] Another objective of this invention is to address the insufficient heat resistance of traditional inks by adding nano-silica and high-temperature resistant additives to the ink. The high-temperature resistant additives are cuprous iodide and potassium iodide; the two together help improve the heat resistance of the ink.

[0007] Another objective of this invention is to improve the color vibrancy of ink by adding nano-titanium dioxide and bio-based brighteners to the ink; the two work synergistically with the dye to make the dye in the ink more vibrant.

[0008] Another objective of this invention is to improve the durability and washability of ink by adding a fixing agent to the ink. The fixing agent is composed of cationic silanized starch, anionic polycarbonate polyurethane dispersion, nano-scale hydrophobic agent, and heat stabilizer. The addition of the fixing agent greatly improves the durability of the ink.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A high-temperature resistant digital printing ink, by weight, comprises the following raw materials: 5-20 parts dye, 0.1-2 parts nano silica, 0.5-1.5 parts cuprous iodide, 1-3.5 parts potassium iodide, 0.1-1 parts nano titanium dioxide, 0.1-1 parts bio-based brightening agent, 1.0-2.5 parts fixing agent, and water to make up to 100 parts.

[0010] The high-temperature resistant additive reacts with dye molecules at high temperatures to form a stable structure, protecting the ink. Cuprous iodide and potassium iodide form coordination complexes with dye molecules at high temperatures, enhancing intermolecular forces through coordination and ionic bonds, inhibiting the thermal decomposition of polymer chains. Cuprous iodide and potassium iodide ensure that the binding force between the dye and fiber does not decrease due to high temperatures after color fixation. Nano-silica disperses in the ink to form a stable network structure, which synergistically protects the ink from the effects of high-temperature environments with the structure formed by the high-temperature resistant additive. Nano-titanium dioxide and nano-silica promote more uniform dispersion of dyes in the ink, and bio-based additives... Brightening agents enhance the binding force between dyes and media through chemical action. The combined effect of these three agents makes the dye color more uniform and vibrant. Nano-titanium dioxide complements the optical effect of the bio-based brightening agent combined with the dye, resulting in a brighter color. The bio-based brightening agent improves light reflection efficiency, and the two work synergistically to further enhance color saturation. The addition of a fixing agent works synergistically with cuprous iodide. Cuprous iodide decomposes into copper ions, which form coordination bonds with the polar groups in the fixing agent, increasing the cross-linking density between fixing agent molecules and forming a denser fixing network. This makes the dye color more stable and the prepared product more durable.

[0011] Preferably, the raw materials include the following by weight: 8-15 parts dye, 0.5-1.5 parts nano silica, 1-1.5 parts cuprous iodide, 2.2-3.5 parts potassium iodide, 0.5-0.8 parts nano titanium dioxide, 0.2-0.8 parts bio-based brightening agent, 1.5-2 parts fixing agent, and water to make up to 100 parts.

[0012] Preferably, the product also includes the following raw materials by weight: 15-25 parts of cosolvent, 0.5-1.5 parts of pH adjuster, 0.1-0.5 parts of antibacterial agent, and 0.1-0.5 parts of defoamer.

[0013] As a preferred option, the dye is one of the following: Yellow 6GFS, Pink FL, Crimson GS, Turquoise S-GL, Brilliant Blue S-2BL, Black 2BSF, Orange S-4RL, Purple (Red) HFRL, Ruby S-5BL, Purple (Blue) BNL, and Dark Blue HGL.

[0014] Preferably, the bio-based brightening agent is one of the following: horse chestnut extract derivative, flavonoids, coumarin derivatives, plant peptides, chitosan, or corn protein. Bio-based brightening agents can optimize the dispersion state of dye molecules, enhance light absorption efficiency, and form intermolecular forces with dyes and attached fibers, thereby reducing dye migration. In addition, bio-based brightening agents can form a thin-layer light interference structure, improve saturation, and make the color more vibrant.

[0015] The color-fixing agent is a composition of cationic silanized starch, anionic polycarbonate polyurethane dispersion, nano-scale hydrophobic agent, and heat stabilizer, with a combination ratio of 1-2:4-6:0.5-1.5:0.01-0.1; the nano-scale hydrophobic agent is PTFE wax powder, and the heat stabilizer is benzotriazole.

[0016] Cationic silanized starch can fix dye molecules through the binding of anions and cations. The silanol groups form stable covalent bonds with the hydroxyl groups on the fiber surface, thus fixing the dye molecules to the fiber through the cationic silanized starch, forming a "fiber-silane-starch-dye" structure, achieving color fixation. Anionic polycarbonate polyurethane dispersions aggregate in the aqueous phase, and as the water evaporates, they form a polymer film that encapsulates the dye molecules. They can also combine with cationic starch to form anion-cation pairs, further enhancing dye curing. PTFE wax powder can form a Vinylon particle film on the dye-fiber molecule surface, thus protecting the dye molecules from loss. Benzotriazole forms a stable complex with the copper ions generated in the high-temperature reinforcing agent, participating in color fixation. Benzotriazole also has antioxidant properties, protecting the dye from oxidation.

[0017] Preferably, the cosolvent is ethylene glycol, and the pH adjuster is one of triethanolamine or ethanolamine.

[0018] This invention also provides a method for preparing a high-temperature resistant digital printing ink: S1. Add dye, potassium halide, nano silica, nano titanium dioxide, cosolvent and water in proportion, and disperse at high speed to obtain dye base; S2. Add cuprous halide and bio-brightening agent to the dye base in one step, remove stirring under vacuum to obtain intermediate; S3. Place the intermediate into a conditioning kettle, adjust the pH, add a color-fixing agent, an antibacterial agent, and an antifoaming agent, and stir and mature under vacuum to obtain a coarse high-temperature resistant digital printing ink. S4. Add the coarse high-temperature resistant digital printing ink to the filter and filter it step by step to obtain the high-temperature resistant digital printing ink.

[0019] Preferably, in step S1, the high-speed dispersion speed is 2000-3000 rpm and the dispersion time is 15-20 min; in step S2, the vacuum negative pressure is -0.05 MPa to -0.06 MPa, the stirring speed is 1200-1400 rpm, and the stirring time is 20-30 min; in step S3, the pH adjustment is 8.4-8.6, the stirring speed is 1500-1800 rpm, and the maturation time is 2-4 h; and in step S4, the step-by-step filtration consists of primary filtration and secondary filtration, with the primary filter screen size being 1-5 μm and the secondary filter screen size being 0.22-0.45 μm.

[0020] The present invention also provides an application of the prepared high-temperature resistant digital printing ink in high-temperature heat transfer digital carpet printing.

[0021] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: The high-temperature digital printing ink prepared by this invention has excellent high-temperature resistance. Through the synergistic effect of nano-silica and high-temperature resistant additives, a stable silica network structure and complex network are formed, which prevents the decomposition of dye molecules and ensures the stability of the ink system in the high-temperature digital printing process.

[0022] The high-temperature digital transfer ink prepared by this invention has excellent durability and washability. Through the synergistic effect of a color-fixing agent and the addition of nano-protection, the color fastness and weather resistance of the ink are comprehensively improved.

[0023] The high-temperature digital transfer ink prepared by this invention has bright colors and saturated patterns. Through the synergistic effect of bio-based brightener and nano titanium dioxide, the light absorption efficiency of dye molecules and the gloss of ink are improved, making the colors brighter. Moreover, the use of bio-based brightener is an environmentally friendly reagent, avoiding pollution.

[0024] The high-temperature digital printing ink prepared by this invention has good dispersion stability. The synergistic effect of nano-silica and nano-titanium dioxide makes the molecules in the ink uniformly dispersed, ensuring stable ink output. Detailed Implementation

[0025] General Implementation Examples Raw materials for high-temperature resistant digital printing ink: dye 10-25 parts, nano silica 1-5 parts, cuprous iodide 0.5-1.5 parts, potassium iodide 1-3.5 parts, nano titanium dioxide 1-10 parts, bio-based brightening agent 1-5 parts, fixing agent 1.0-2.5 parts, cosolvent 15-25 parts, pH adjuster 0.5-1.5 parts, antibacterial agent 0.1-0.5 parts, defoamer 0.1-0.5 parts, water 40-60 parts; the bio-based brightening agent is one of the following: horse chestnut extract derivative, flavonoids, coumarin derivatives, plant peptides, chitosan, and corn protein; the cosolvent is ethylene glycol; and the pH adjuster is one of triethanolamine and ethanolamine. Fixing agent formulation: The ratio of cationic silanized starch, anionic polycarbonate polyurethane dispersion, PTFE wax powder, and benzotriazole is 1-2:4-6:0.5-1.5:0.01-0.1.

[0026] Preparation method: includes the following steps: S1. Add dye, potassium iodide, nano silica, nano titanium dioxide, ethylene glycol and water to a high-speed disperser according to the proportion. The high-speed dispersion speed is 2000-3000 rpm and the dispersion time is 15-20 min to obtain the dye base. S2. Add cuprous iodide and bio-brightening agent to the dye base in sequence. Under a vacuum pressure of -0.05MPa to -0.06MPa, stir at a speed of 1200-1400rpm for 20-30min to obtain the intermediate. S3. Place the intermediate in a conditioning kettle, add triethanolamine to adjust the pH to 8.4-8.6, then add fixing agent, antibacterial agent, defoamer, and stir and mature under vacuum negative pressure of -0.05MPa to -0.06MPa at a stirring speed of 1500-1800rpm for 2-4 hours to obtain coarse high temperature resistant digital printing ink. S4. Coarse, high-temperature resistant digital printing ink is added to the filter step by step. First, it passes through a primary filter screen of 10-20μm, and then through a secondary filter screen of 0.5-1μm to obtain high-temperature resistant digital printing ink.

[0027] Example 1 Raw materials for high-temperature resistant digital printing ink: 20 parts dye, 3 parts nano silica, 1 part cuprous iodide, 2.2 parts potassium iodide, 5 parts nano titanium dioxide, 3 parts horse chestnut extract derivative, 2.0 parts fixing agent, 10 parts ethylene glycol, 1 part triethanolamine, 0.3 parts antibacterial agent, 0.4 parts defoamer, and 50 parts water. Fixing agent formulation: The ratio of cationic silanized starch, anionic polycarbonate polyurethane dispersion, PTFE wax powder, and benzotriazole is 1.5:5:1:0.05; Preparation method: includes the following steps: S1. Add dye, potassium iodide, nano silica, nano titanium dioxide, ethylene glycol and water to a high-speed disperser according to the proportion. The high-speed dispersion speed is 2500 rpm and the dispersion time is 18 min to obtain the dye base. S2. Cuprous iodide and bio-brightening agent were added to the dye base in sequence. The mixture was stirred under a vacuum of -0.07 MPa at a speed of 1300 rpm for 25 min to obtain the intermediate. S3. Place the intermediate in a conditioning kettle, add triethanolamine to adjust the pH to 8.4-8.6, then add fixing agent, antibacterial agent, defoamer, and stir and mature under vacuum negative pressure of -0.095MPa-MPa at a stirring speed of 1650rpm for 3h to obtain coarse high temperature resistant digital printing ink. S4. Coarse, high-temperature resistant digital printing ink is added to the filter step by step. It first passes through a primary filter screen of 18μm, and then through a secondary filter screen of 0.8μm to obtain high-temperature resistant digital printing ink.

[0028] The preparation methods of Examples 2-12 are the same as those of Example 1, and the composition of the fixing agent is the same as that of Example 1.

[0029] Example 2 Raw materials for high-temperature resistant digital printing ink: 22 parts dye, 1 part nano silica, 1 part cuprous iodide, 2.2 parts potassium iodide, 1 part nano titanium dioxide, 3 parts horse chestnut extract derivative, 2.0 parts fixing agent, 10 parts ethylene glycol, 1 part triethanolamine, 0.3 parts antibacterial agent, 0.4 parts defoamer, and 52 parts water.

[0030] Example 3 Raw materials for high-temperature resistant digital printing ink: 25 parts dye, 5 parts nano silica, 1 part cuprous iodide, 2.2 parts potassium iodide, 10 parts nano titanium dioxide, 3 parts horse chestnut extract derivative, 2.0 parts fixing agent, 10 parts ethylene glycol, 1 part triethanolamine, 0.3 parts antibacterial agent, 0.4 parts defoamer, and 50 parts water.

[0031] Example 4 Raw materials for high-temperature resistant digital printing ink: 15 parts dye, 4 parts nano silica, 1 part cuprous iodide, 2.2 parts potassium iodide, 8 parts nano titanium dioxide, 3 parts horse chestnut extract derivative, 2.0 parts fixing agent, 10 parts ethylene glycol, 1 part triethanolamine, 0.3 parts antibacterial agent, 0.4 parts defoamer, and 50 parts water.

[0032] Example 5 Raw materials for high-temperature resistant digital printing ink: 10 parts dye, 2 parts nano silica, 1 part cuprous iodide, 2.2 parts potassium iodide, 3 parts nano titanium dioxide, 3 parts horse chestnut extract derivative, 2.0 parts fixing agent, 10 parts ethylene glycol, 1 part triethanolamine, 0.3 parts antibacterial agent, 0.4 parts defoamer, and 50 parts water.

[0033] Examples 1-5 are studies on the effects of different amounts of dye and different amounts of nano-silica and nano-titanium dioxide on the performance of ink. By adjusting the amount of dye and nanomaterials added, the degree of dye dispersion can be adjusted.

[0034] Example 6 Raw materials for high-temperature resistant digital printing ink: 20 parts dye, 3 parts nano silica, 0.5 parts cuprous iodide, 1 part potassium iodide, 5 parts nano titanium dioxide, 3 parts horse chestnut extract derivative, 2.0 parts fixing agent, 10 parts ethylene glycol, 1 part triethanolamine, 0.3 parts antibacterial agent, 0.4 parts defoamer, and 50 parts water.

[0035] Example 7 Raw materials for high-temperature resistant digital printing ink: 20 parts dye, 3 parts nano silica, 1.5 parts cuprous iodide, 3.5 parts potassium iodide, 5 parts nano titanium dioxide, 3 parts horse chestnut extract derivative, 2.0 parts fixing agent, 10 parts ethylene glycol, 1 part triethanolamine, 0.3 parts antibacterial agent, 0.4 parts defoamer, and 50 parts water.

[0036] Example 8 Raw materials for high-temperature resistant digital printing ink: 20 parts dye, 3 parts nano silica, 1 part cuprous iodide, 2.2 parts potassium iodide, 5 parts nano titanium dioxide, 1 part horse chestnut extract derivative, 2.0 parts fixing agent, 10 parts ethylene glycol, 1 part triethanolamine, 0.3 parts antibacterial agent, 0.4 parts defoamer, and 50 parts water.

[0037] Examples 1 and 6-8 prepared different inks by adjusting the amount of high-temperature reinforcing agent and the different combinations and ratios of cuprous iodide and potassium iodide, which can be used to study the direct effect of high-temperature reinforcing agent on the high-temperature resistance of ink.

[0038] Example 9 Raw materials for high-temperature resistant digital printing ink: 20 parts dye, 3 parts nano silica, 1 part cuprous iodide, 2.2 parts potassium iodide, 5 parts nano titanium dioxide, 3 parts horse chestnut extract derivative, 2.0 parts fixing agent, 10 parts ethylene glycol, 1 part triethanolamine, 0.3 parts antibacterial agent, 0.4 parts defoamer, and 50 parts water.

[0039] Example 10 Raw materials for high-temperature resistant digital printing ink: 20 parts dye, 3 parts nano silica, 1 part cuprous iodide, 2.2 parts potassium iodide, 5 parts nano titanium dioxide, 5 parts horse chestnut extract derivative, 2.0 parts fixing agent, 10 parts ethylene glycol, 1 part triethanolamine, 0.3 parts antibacterial agent, 0.4 parts defoamer, and 50 parts water.

[0040] Examples 9-10 illustrate the effect of the amount of bio-based brightening agent added on ink performance.

[0041] Example 11 Raw materials for high-temperature resistant digital printing ink: 20 parts dye, 3 parts nano silica, 1 part cuprous iodide, 2.2 parts potassium iodide, 5 parts nano titanium dioxide, 3 parts horse chestnut extract derivative, 1.0 part fixing agent, 10 parts ethylene glycol, 1 part triethanolamine, 0.3 parts antibacterial agent, 0.4 parts defoamer, and 50 parts water.

[0042] Example 12 Raw materials for high-temperature resistant digital printing ink: 20 parts dye, 3 parts nano silica, 1 part cuprous iodide, 2.2 parts potassium iodide, 5 parts nano titanium dioxide, 3 parts horse chestnut extract derivative, 2.5 parts fixing agent, 10 parts ethylene glycol, 1 part triethanolamine, 0.3 parts antibacterial agent, 0.4 parts defoamer, and 50 parts water.

[0043] Examples 11-12 illustrate the effect of the amount of fixing agent added on ink performance.

[0044] Table 1. Raw material addition amounts for Examples 1-12 Examples 1-12 illustrate the effects of the amounts of dye, nano-silica, high-temperature resistant additives, nano-titanium dioxide, bio-based brightening agents, and fixing agents added to the ink formulation on ink performance. Examples 1-5 examine the relationship between the amounts of nano-silica, nano-titanium dioxide, and dye added. Nano-silica and nano-titanium dioxide can improve ink dispersibility. Furthermore, nano-silica can enhance the heat resistance of the ink, while nano-titanium dioxide can improve the ink's vibrancy. Examples 6-8 discuss the effects of high-temperature reinforcing agents on ink. Cuprous iodide and potassium iodide react with the dye, and the copper ions generated from their decomposition can synergistically work with the fixing agent, ensuring that the bond between the dye and fiber does not decompose at high temperatures. Examples 9-10 illustrate the effects of the amount of bio-based brightening agents added on ink. Bio-based brightening agents and nano-titanium dioxide synergistically improve the ink's vibrancy. Examples 11-12 discuss the effects of the amount of fixing agents added on ink. The addition of fixing agents can effectively improve the bond between the dye and fiber, enhancing the water resistance of the printed product.

[0045] Examples 13-17 refer to Example 1, but the bio-enhancing agent in Example 1 is replaced in sequence with flavonoids, coumarin derivatives, plant peptides, chitosan, and corn protein. The other formulations and preparation methods are the same as in Example 1.

[0046] Example 18 Fixing agent formulation: The ratio of cationic silanized starch, anionic polycarbonate polyurethane dispersion, PTFE wax powder, and benzotriazole is 1:4:0.5:0.01. Example 18 is based on Example 1, but the ratio of the fixing agent is changed to the minimum ratio.

[0047] Example 19 Fixing agent formulation: The ratio of cationic silanized starch, anionic polycarbonate polyurethane dispersion, PTFE wax powder, and benzotriazole is 2:6:1.5:0.1. Example 19 is based on Example 1, but the ratio of the fixing agent is changed to the maximum ratio.

[0048] The following Comparative Examples 1-4 are comparisons with Example 1, and the preparation methods and fixing agent formulations are the same as those in Example 1.

[0049] Comparative Example 1 Raw materials for high-temperature resistant digital printing ink: 20 parts dye, 1 part cuprous iodide, 2.2 parts potassium iodide, 3 parts horse chestnut extract derivative, 2.0 parts fixing agent, 10 parts ethylene glycol, 1 part triethanolamine, 0.3 parts antibacterial agent, 0.4 parts defoamer, and 50 parts water.

[0050] Comparative Example 2 Raw materials for high-temperature resistant digital printing ink: 20 parts dye, 3 parts nano silica, 5 parts nano titanium dioxide, 3 parts horse chestnut extract derivative, 2.0 parts fixing agent, 10 parts ethylene glycol, 1 part triethanolamine, 0.3 parts antibacterial agent, 0.4 parts defoamer, and 50 parts water.

[0051] Comparative Example 3 Raw materials for high-temperature resistant digital printing ink: 20 parts dye, 3 parts nano silica, 1 part cuprous iodide, 2.2 parts potassium iodide, 5 parts nano titanium dioxide, 2.0 parts fixing agent, 10 parts ethylene glycol, 1 part triethanolamine, 0.3 parts antibacterial agent, 0.4 parts defoamer, and 50 parts water.

[0052] Comparative Example 4 Raw materials for high-temperature resistant digital printing ink: 20 parts dye, 3 parts nano silica, 1 part cuprous iodide, 2.2 parts potassium iodide, 5 parts nano titanium dioxide, 3 parts horse chestnut extract derivative, 10 parts ethylene glycol, 1 part triethanolamine, 0.3 parts antibacterial agent, 0.4 parts defoamer, and 50 parts water.

[0053] Table 2. Raw material ratios for Example 1 and Comparative Examples 1-4 Comparative Example 1 lacked nano-silica and nano-titanium dioxide, Comparative Example 2 lacked cuprous iodide and potassium iodide, Comparative Example 3 lacked bio-based brightening agent, and Comparative Example 4 lacked color-fixing agent.

[0054] Performance testing High-temperature resistant digital printing inks were prepared according to the above embodiments and comparative examples, and samples were taken for testing. High temperature resistance test: test temperature 200-300℃, time 16-24 hours, the standard adopted is "QB / T4538-2013"; The ink was transferred onto the carpet, the digital printing temperature was set to 280℃, and the color difference was measured with a colorimeter.

[0055] Color vibrancy test: Instrument: spectrophotometer, measuring hue and saturation, and comparing with a standard color chart.

[0056] Color fastness test: Wash the transferred carpet with detergent at 60℃ for 30 minutes, repeat 5 times; determine the color fastness to washing according to GB / T5713-2013.

[0057] Table 3 Performance Test Results Name / Performance Test High temperature resistance test (color difference) Color saturation (%) Color fastness to washing / grade Example 1 0.61 94.1 5 Example 2 0.92 94.3 5 Example 3 0.47 94.2 5 Example 4 0.52 93.7 5 Example 5 0.35 97.2 5 Example 6 1.02 95.7 5 Example 7 0.41 96.2 5 Example 8 0.44 96.1 5 Example 9 0.77 89.2 5 Example 10 0.72 96.6 5 Example 11 0.83 92.3 4 Example 12 0.65 95.4 5 Comparative Example 1 1.22 91.7 3 Comparative Example 2 3.19 93.4 4 Comparative Example 3 0.71 75.2 3 Comparative Example 4 1.63 82.1 2 As shown in the test results in the table above, the high-temperature resistant digital printing inks of Examples 1-12 have good high-temperature resistance and washability, and vibrant colors. Examples 1-5 show that the addition of nano-silica and nano-titanium dioxide has a significant impact on the high-temperature resistance and color saturation of the ink. Nano-silica can not only prevent the agglomeration of other raw materials and maintain the uniformity of the ink, but also protect the dye molecules from decomposition at high temperatures. Nano-titanium dioxide can not only delay the photodegradation of dyes, but also significantly enhance the optical properties of the ink due to its high refractive index, thereby improving the color saturation. The nano-titanium dioxide is evenly distributed on the dye-fiber surface, making the printed pattern more vibrant.

[0058] Examples 6-8 illustrate the effect of the addition of cuprous iodide and potassium iodide on ink. Cuprous iodide and potassium iodide are ionic halides. During ink processing, cuprous iodide and potassium iodide can form a stable chemical phase to encapsulate the dye, preventing the dye from degrading due to high temperature during preparation. The heat resistance of this ink is not only good during use, but the printed pattern is also very tightly bonded to the fiber. The cuprous ions in cuprous iodide are converted into copper ions, which work synergistically with the anions and cations in the fixing agent to enhance the binding of the dye to the fiber and improve the high temperature resistance of the ink.

[0059] Examples 9-10 illustrate the effect of the amount of bio-based brightening agent added on ink. Bio-based brightening agents can optimize the dye dispersion state. Bio-based brightening agents have hydrophilic and hydrophobic groups. The hydrophilic groups form hydrogen bonds with water or polar solvents, increasing the steric hindrance between molecules. Bio-based brightening agents can bind to the fiber surface, assisting the fiber-silane-starch-dye linkage in the fixing agent and enhancing the dye-fiber interaction. Bio-based brightening agents can penetrate the fiber surface, allowing the dye to bind to the fiber through other pathways, improving optical efficiency and protecting dye stability.

[0060] Examples 11-12 describe the effect of fixing agents on inks. Fixing agents are the core functional components that ensure the durable bonding between dyes and fibers. Through multiple mechanisms such as chemical bonding, physical encapsulation, and interfacial synergy, they inhibit dye loss or migration under external factors such as washing and high temperatures. The synergistic effects of cationic silanized starch covalent anchoring, anionic polycarbonate polyurethane dispersion encapsulating the dye, PTFE wax powder physical protection, and benzotriazole antioxidant protection achieve a wash resistance rating of ≥5.

[0061] The comparative examples, lacking necessary technical solutions, showed significantly inferior performance compared to the examples in relevant testing methods. Comparative Example 1, without the addition of nano-silica and nano-titanium dioxide, exhibited decreased high-temperature resistance, reduced color vibrancy, and decreased water resistance. The absence of nanomaterials resulted in uneven dispersion and the lack of high-temperature protection from nano-silica, hindering the improvement of color from nano-titanium dioxide; in particular, the high-temperature resistance was significantly reduced. Comparative Example 2, lacking cuprous iodide and potassium iodide, and relying solely on nano-silica for high-temperature protection, resulted in very poor high-temperature resistance. Comparative Example 3, without bio-based brightening agents, showed a significant decrease in color vibrancy; nano-titanium dioxide alone was insufficient to achieve high color vibrancy. Comparative Example 4, lacking a fixing agent, resulted in the disappearance of key binding points between the dye and fiber. Although other raw materials could improve the binding between dye and fiber, experimental results showed insufficient bonding strength. The results of these comparative examples, compared with Example 1, clearly demonstrate the importance of the specific technical solutions defined in this invention for its technical effectiveness.

[0062] Table 4 Performance test results of Examples 13-19 Name / Performance Test High temperature resistance test (color difference) Color saturation (%) Color fastness to washing / grade Example 13 0.60 94.2 5 Example 14 0.62 94.1 5 Example 15 0.61 93.9 5 Example 16 0.59 93.8 5 Example 17 0.61 93.7 5 Example 18 0.62 94.1 5 Example 19 0.59 94.3 5 As can be seen from the table above, Examples 13-17 demonstrate that the color saturation test results of inks prepared with different bio-based brightening agents provided by the present invention show little difference; Examples 18-19 are about different proportions of fixing agents, and the experimental results show that the selection of fixing agents in the present invention can effectively improve the washability of the product.

Claims

1. A high-temperature resistant digital printing ink, characterized in that, By weight, it includes the following raw materials: 10-25 parts dye, 1-5 parts nano silica, 0.5-1.5 parts cuprous iodide, 1-3.5 parts potassium iodide, 1-10 parts nano titanium dioxide, 1-5 parts bio-based brightening agent, 1.0-2.5 parts fixing agent, and 40-60 parts water.

2. The high-temperature resistant digital printing ink according to claim 1, characterized in that, By weight, it includes the following raw materials: 15-20 parts dye, 2-4 parts nano silica, 1-1.5 parts cuprous iodide, 2.2-3.5 parts potassium iodide, 3-7 parts nano titanium dioxide, 2-3 parts bio-based brightening agent, 1.5-2 parts fixing agent, and 40-60 parts water.

3. The high-temperature resistant digital printing ink according to claim 1, characterized in that, By weight, it also includes the following raw materials: 15-25 parts of cosolvent, 0.5-1.5 parts of pH adjuster, 0.1-0.5 parts of antibacterial agent, and 0.1-0.5 parts of defoamer.

4. A high-temperature resistant digital printing ink according to claim 1 or 2, characterized in that, The dye is one of the following: Yellow 6GFS, Pink FL, Crimson GS, Turquoise S-GL, Brilliant Blue S-2BL, Black 2BSF, Orange S-4RL, Purple (Red) HFRL, Ruby S-5BL, Purple (Blue) BNL, and Dark Blue HGL.

5. A high-temperature resistant digital printing ink according to claim 1 or 2, characterized in that, The bio-enhancing agent is one of the following: horse chestnut extract derivative, flavonoids, coumarin derivatives, plant peptides, chitosan, or corn protein.

6. A high-temperature resistant digital printing ink according to claim 1 or 2, characterized in that, The color-fixing agent is a composition of cationic silanized starch, anionic polycarbonate polyurethane dispersion, nano-scale hydrophobic agent, and heat stabilizer, with a combination ratio of 1-2:4-6:0.5-1.5:0.01-0.1; the nano-scale hydrophobic agent is PTFE wax powder, and the heat stabilizer is benzotriazole.

7. The high-temperature resistant digital printing ink according to claim 3, characterized in that, The cosolvent is ethylene glycol, and the pH adjuster is one of triethanolamine or ethanolamine.

8. A method for preparing a high-temperature resistant digital printing ink, characterized in that, The preparation of a high-temperature resistant digital printing ink according to any one of claims 1-7 comprises the following steps: S1. Add dye, potassium iodide, nano silica, nano titanium dioxide, cosolvent and water in proportion, and disperse at high speed to obtain dye base; S2. Cuprous iodide and bio-brightening agent are added sequentially to the dye base. The mixture is removed from the stirring under vacuum to obtain the intermediate. S3. Place the intermediate into a conditioning kettle, adjust the pH, add a color-fixing agent, an antibacterial agent, and an antifoaming agent, and stir and mature under vacuum to obtain a coarse high-temperature resistant digital printing ink. S4. Add the coarse high-temperature resistant digital printing ink to the filter and filter it step by step to obtain the high-temperature resistant digital printing ink.

9. The method for preparing a high-temperature resistant digital printing ink according to claim 8, wherein the high-speed dispersion speed in S1 is 2000-3000 rpm and the dispersion time is 15-20 min; the vacuum environment in S2 is -0.05 MPa to -0.08 MPa, the stirring speed is 1200-1400 rpm, and the stirring time is 20-30 min; the vacuum environment in S3 is -0.09 MPa to -0.10 MPa, the pH is adjusted to 8.4-8.6, the stirring speed is 1500-1800 rpm, and the maturation time is 2-4 h; the stepwise filtration in S4 consists of primary filtration and secondary filtration, wherein the filter screen size of the primary filtration is 10-20 μm and the filter screen size of the secondary filtration is 0.5-1 μm.

10. The application of the high-temperature resistant digital printing ink prepared according to claim 8 in high-temperature heat transfer digital carpet printing.

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