High viscosity digital printing cationic ink and preparation method thereof

Abstract

This application discloses a high-viscosity digital printing cationic ink and its preparation method. The high-viscosity digital printing cationic ink comprises the following components by weight percentage: 2.5-8.0% cationic dye, 20-60% solvent, 6-30% co-solvent, 0.1%-1.0% surfactant, 1-3% high-viscosity additive, 0.1-1% pH adjuster, 0.1-1% bactericide, and the balance being deionized water.

Description

Technical Field

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

[0002] With the development and popularization of digital technology, the volume of digital printing on carpets has maintained a growth trend. Currently, carpet materials on the market include nylon, acrylic, polyester, and modified polyester, among others. There are also a wide variety of inks available, such as acid inks, cationic inks, and disperse inks. The difference between polyester and modified polyester lies in their properties. Polyester fibers have advantages such as high strength, good rigidity, good elasticity, water resistance, and lightfastness, but disadvantages include difficulty in dyeing, insufficient color depth after dyeing, and less vibrant colors. Modified polyester, on the other hand, is a new type of fiber created by adding modifiers to alter the structure of the polyester fiber itself, allowing it to undergo cation exchange with cationic dyes, thus resulting in deeper and more vibrant colors.

[0003] High-temperature disperse inks dominate the market for digital carpet printing. Their advantages include excellent penetration, a wide color range, and vibrant, layered colors in printed fabrics. However, they also have drawbacks, such as more complex processing and poorer colorfastness to rubbing and washing. Modified polyester is more absorbent, softer, and easier to dye than ordinary polyester, and it is also relatively cheaper, making it more widely used. However, modified polyester is not heat-resistant, and its color development temperature generally cannot exceed 140℃. If disperse dyes are used, insufficient color development and floating color may occur, requiring washing to improve colorfastness. With the rapid increase in digital printing orders and the continuous improvement of digital printing technology, customer demands are rising. Cationic dyes produce rich, vibrant colors, excellent dyeing performance, and good colorfastness across various properties. They exhibit high lightfastness on acrylic fibers, surpassing other types of dye inks, and can be applied to modified polyester carpet fabrics, resulting in vibrant colors and superior performance. Cationic dye ink printing has the advantages of bright colors, high penetration on carpets, high light fastness, low energy consumption for evaporation, and energy saving and environmental protection. With the treatment of the color fixing agent, the finished product can also be waterless, reducing wastewater discharge and reducing the pollution pressure on enterprises.

[0004] Patent CN102102303, issued by Jiangnan University, uses cationic dispersants and dispersed dyes to grind together to form cationic dispersed color pastes, which are then compounded with auxiliaries to obtain cationic dispersed inks. Patent CN1276036 from Beijing Institute of Fashion Technology proposes alkaline dye and cationic dye inks, requiring fabric pretreatment during digital printing. Chinese patent CN108486933 proposes a dispersed cationic dye inkjet ink and its digital printing process, using a dispersed cationic dye color paste made by grinding cationic dyes with dispersants and blocking agents. Chinese patent CN110872789 mainly introduces a composition of cationic dye ink for digital inkjet printing, applicable to acrylic fibers or cationic dyeable polyester fibers. Combined with pretreatment processes, it can give printed textiles excellent overall color performance. US patent US6136080 proposes a cationic azo dye yellow for inkjet inks, representing the development of a cationic dye structure. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides a high-viscosity digital printing cationic ink, wherein the high-viscosity digital printing cationic ink comprises the following components by weight percentage:

[0006] Cationic dyes 2.5-8.0%

[0007] Solvent 20-60%

[0008] Cosolvent 6-30%

[0009] Surfactant 0.1%-1.0%

[0010] High viscosity additive 1-3%

[0011] pH adjuster 0.1-1%

[0012] 0.1-1% of bactericide

[0013] The remainder is deionized water.

[0014] According to one embodiment of this application, the viscosity of the ink ranges from 8 to 20 cps, with an optimal range of 12 to 15 cps.

[0015] According to one embodiment of this application, the surface tension of the ink ranges from 30 to 50 mN / m, with an optimal range of 35 to 45 mN / m.

[0016] According to one embodiment of this application, the pH range of the ink is 5.5-6.5.

[0017] According to one embodiment of this application, the cationic dye includes at least one or three dyes selected from CI cationic yellow 28, CI cationic yellow 19, CI cationic yellow 51, CI cationic red 46, CI cationic blue 3, CI cationic blue 41, and CI cationic blue 159.

[0018] According to one embodiment of this application, the solvent is a mixture of at least two of the following: ethylene glycol, propylene glycol, diethylene glycol, glycerol, 1,2-pentanediol, 1,4-butanediol, dipropylene glycol, and 1,4-cyclohexyldiethanol.

[0019] According to one embodiment of this application, the cosolvent is a mixture of at least two of propylene glycol monomethyl ether, N-methylformamide, N-methylpyrrolidone, 2-pyrrolidone, caprolactam, ethylene glycol butyl ether, and diethylene glycol monobutyl ether.

[0020] According to one embodiment of this application, the surfactant is one or a mixture of acetylenic diols, polyoxyethylene ethers, macromolecular polyether modified acrylates, Dynol 607, BYK3566, BYK094, Airase5100, Surfynol 440, Surfynol 465, Surfynol104, and Auk TL-J65A.

[0021] According to one embodiment of this application, it satisfies at least one of the following conditions:

[0022] The surfactant used is an acetylenic diol wetting agent combined with a macromolecular polyether leveling agent;

[0023] The high viscosity additive is one or a mixture of any two of the following: PPG200, PEG400, PEG6000, G300, polypropylene glycol, polyglycerol, ethyl cellulose, and polyvinylpyrrolidone.

[0024] The bactericide is GXL;

[0025] The pH adjuster is selected from at least one of Dow's AMP-95, triethanolamine, diethanolamine, and Tris base.

[0026] According to another aspect of this application, a method for preparing high-viscosity digital printing cationic ink is also provided, comprising the following steps:

[0027] S01, according to the preset ratio of high viscosity digital printing cationic ink, the cationic raw powder is mixed and dissolved with deionized water, the pH is adjusted to acidic, then alkali is added to precipitate, and filtered to obtain refined cationic raw material;

[0028] S102, turn on the mixer, add water, preferably add solvent, cosolvent, surfactant, bactericide and pH adjuster while stirring at a speed of 400-600 rpm, stir evenly, preferably for 20-30 min, add the cationic raw material obtained in step S101, and continue to stir and mix evenly at a speed of 600-800 rpm, preferably for 120-240 min;

[0029] S103, after feeding, test the viscosity and surface tension. The optimal viscosity range is 12-15.0 cps, and the optimal surface tension range is 40-45 mN / m. Adjust the pH to 5.5-6.5. Detailed Implementation

[0030] The following description is intended to disclose this application and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of this application defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of this application.

[0031] According to one aspect of this application, a high-viscosity digital printing cationic ink according to a preferred embodiment of this application will be described in detail below, wherein the high-viscosity digital printing cationic ink comprises the following components by weight percentage:

[0032] Cationic dyes 2.5-8.0%

[0033] Solvent 20-60%

[0034] Cosolvent 6-30%

[0035] Surfactant 0.1%-1.0%

[0036] High viscosity additive 1-3%

[0037] pH adjuster 0.1-1%

[0038] 0.1-1% of bactericide

[0039] The remainder is deionized water.

[0040] Preferably, the ink viscosity ranges from 8 to 20 cps, with an optimal range of 12 to 15 cps.

[0041] Preferably, the surface tension ranges from 30 to 50 mN / m, with the optimal range being 35 to 45 mN / m.

[0042] Preferably, the pH range is 5.5-6.5.

[0043] Preferably, the cationic dye includes at least one or three dyes selected from CI cationic yellow 28, CI cationic yellow 19, CI cationic yellow 51, CI cationic red 46, CI cationic blue 3, CI cationic blue 41, and CI cationic blue 159.

[0044] Preferably, the solvent is a mixture of at least two of the following: ethylene glycol, propylene glycol, diethylene glycol, glycerol, 1,2-pentanediol, 1,4-butanediol, dipropylene glycol, and 1,4-cyclohexyldiethanol.

[0045] Preferably, the co-solvent is a mixture of at least two of the following: propylene glycol monomethyl ether, N-methylformamide, N-methylpyrrolidone, 2-pyrrolidone, caprolactam, ethylene glycol butyl ether, and diethylene glycol monobutyl ether.

[0046] Preferably, the surfactant is one or a mixture of two or more of the following: acetylenic diols, polyoxyethylene ethers, macromolecular polyether modified acrylates, Dynol 607, BYK 3566, BYK 094, Airase 5100, Surfynol 440, Surfynol 465, Surfynol 104, and Auk TL-J65A.

[0047] More preferably, the surfactant uses an acetylenic diol wetting agent combined with a macromolecular polyether leveling agent. The optimal printing effect is achieved when the wetting agent to leveling agent ratio is between 2:1 and 4:1.

[0048] Preferably, the high-viscosity additive is one or a mixture of any two of the following: PPG200, PEG400, PEG6000, G300, polypropylene glycol, polyglycerol, ethyl cellulose, and polyvinylpyrrolidone.

[0049] Preferably, the bactericide is GXL.

[0050] Preferably, the pH adjuster is selected from at least one of Dow's AMP-95, triethanolamine, diethanolamine, and Tris base.

[0051] According to another aspect of this application, a method for preparing a high-viscosity digital printing cationic ink is also provided, comprising the following steps:

[0052] S01, Refining of cationic raw materials: Specifically, according to the proportion of the high-viscosity digital printing cationic ink mentioned above, the cationic raw powder is mixed and dissolved with deionized water, the pH is adjusted to acidic, then alkali is added to precipitate, and the mixture is filtered to obtain refined cationic raw materials.

[0053] S102, Ink preparation, specifically, turn on the mixer, add water, and preferably add solvent, co-solvent, surfactant, bactericide and pH adjuster while stirring at a speed of 400-600 rpm, stir evenly, preferably for 20-30 min, add the cationic raw material obtained in step S101, and continue to stir and mix evenly at a speed of 600-800 rpm, preferably for 120-240 min.

[0054] S103, aging and filtration, specifically, after feeding, test the viscosity and surface tension. The optimal viscosity range is 12-15.0 cps, and the optimal surface tension range is 40-45 mN / m. Adjust the pH to 5.5-6.5.

[0055] After passing the test, the ink is aged at 15-35℃ for 24-48 hours to ensure complete dissolution of the ink components and equilibrium of the system, while insoluble substances and unstable colloids precipitate out. After aging, the ink is first filtered under positive pressure using a 1.0μm glass fiber filter to remove large particles and colloids, then secondly filtered under positive pressure using a 0.65μm nylon filter to remove smaller precipitates, and finally filtered under positive pressure using a 0.45μm polyethylene sulfone pleated filter to obtain the final product.

[0056] test

[0057] a. Stability test: After filtering, the ink was heated in an oven at 60℃ for 7 days, frozen in a freezer at -18℃ for 7 days, and then left to stand at room temperature for 12 hours to test the physical and chemical properties and filtration performance of the ink.

[0058] b. Printing performance test: After filtering the ink, the printing performance was tested using an SG1024 machine.

[0059] Example 1

[0060] In sequence, 24.05 parts by weight of deionized water, 22 parts by weight of diethylene glycol, 20 parts by weight of ethylene glycol, 8 parts by weight of PEG400, 10 parts by weight of caprolactam, 12 parts by weight of ethylene glycol butyl ether, 0.15 parts by weight of surfactant BYK3566, 1.0 part by weight of GXL, and 2.8 parts by weight of cationic blue 3 are placed in a container and stirred at a high speed of 600 rpm for 120 minutes. The mixture is then aged at 25°C for 24 hours to allow the ink components to completely dissolve and the system to reach equilibrium, with insoluble substances and unstable colloids precipitating out. After aging, the ink is first filtered through a 1.0 μm glass fiber filter under positive pressure to remove large particles and impurities, followed by a second filtration through a 0.65 μm nylon filter under positive pressure to remove flocculent gels and smaller precipitates. Finally, it is filtered through a 0.45 μm polyvinyl sulfone pleated filter under positive pressure to obtain the finished ink product.

[0061] Example 2

[0062] In the following order, 24.7 parts by weight of deionized water, 22 parts by weight of diethylene glycol, 20 parts by weight of ethylene glycol, 8 parts by weight of PEG400, 10 parts by weight of caprolactam, 12 parts by weight of ethylene glycol butyl ether, 0.5 parts by weight of surfactant BYK3566, 1.0 part by weight of GXL, and 2.8 parts by weight of cationic blue 3 were placed in a container and stirred at a high speed of 600 rpm for 120 minutes. The mixture was then aged at 25°C for 24 hours to allow the ink components to completely dissolve and the system to reach equilibrium, with insoluble substances and unstable colloids precipitating out. After aging, the ink was first filtered through a 1.0 μm glass fiber filter under positive pressure to remove large particles and impurities, followed by a second filtration through a 0.65 μm nylon filter under positive pressure to remove flocculent gels and smaller precipitates. Finally, it was filtered through a 0.45 μm polyvinyl sulfone pleated filter under positive pressure to obtain the finished ink product.

[0063] Example 3

[0064] In a specific order, 24.7 parts by weight of deionized water, 22 parts by weight of diethylene glycol, 20 parts by weight of ethylene glycol, 8 parts by weight of PEG400, 10 parts by weight of caprolactam, 12 parts by weight of ethylene glycol butyl ether, 0.5 parts by weight of surfactant Surfynol 465, 1.0 part by weight of GXL, and 2.8 parts by weight of cationic blue 3 were placed in a container and stirred at a high speed of 600 rpm for 120 minutes. The mixture was then aged at 25°C for 24 hours to allow the ink components to completely dissolve and the system to reach equilibrium, resulting in the precipitation of insoluble substances and unstable colloids. After aging, the ink was first filtered through a 1.0 μm glass fiber filter under positive pressure to remove large particles and impurities, followed by a second filtration through a 0.65 μm nylon filter under positive pressure to remove flocculent gels and smaller precipitates. Finally, it was filtered through a 0.45 μm polyvinyl sulfone pleated filter under positive pressure to obtain the finished ink product.

[0065] Example 4

[0066] In a specific order, 24.9 parts by weight of deionized water, 22 parts by weight of diethylene glycol, 20 parts by weight of ethylene glycol, 8 parts by weight of PEG400, 10 parts by weight of caprolactam, 12 parts by weight of ethylene glycol butyl ether, 0.15 parts by weight of surfactant Surfynol 465, 0.15 parts by weight of surfactant BYK3566, 1.0 part by weight of GXL, and 2.8 parts by weight of cationic blue 3 were placed in a container and stirred at a high speed of 600 rpm for 120 minutes. The mixture was then aged at 25°C for 24 hours to allow the ink components to completely dissolve and the system to reach equilibrium, resulting in the precipitation of insoluble substances and unstable colloids. After aging, the ink was first filtered through a 1.0 μm glass fiber filter under positive pressure to remove large particles and impurities, followed by a second filtration through a 0.65 μm nylon filter under positive pressure to remove flocculent gels and smaller precipitates. Finally, it was filtered through a 0.45 μm polyethylene sulfone pleated filter under positive pressure to obtain the finished ink product.

[0067] Example 5

[0068] In the following order, 23.55 parts by weight of deionized water, 22 parts by weight of diethylene glycol, 20 parts by weight of ethylene glycol, 8 parts by weight of PEG400, 10 parts by weight of caprolactam, 12 parts by weight of ethylene glycol butyl ether, 0.5 parts by weight of surfactant Surfynol 465, 0.15 parts by weight of surfactant BYK3566, 1.0 part by weight of GXL, and 2.8 parts by weight of cationic blue 3 were placed in a container and stirred at a high speed of 600 rpm for 120 minutes. The mixture was then aged at 25°C for 24 hours to allow the ink components to completely dissolve and the system to reach equilibrium, with insoluble substances and unstable colloids precipitating out. After aging, the ink was first filtered through a 1.0 μm glass fiber filter under positive pressure to remove large particles and impurities, followed by a second filtration through a 0.65 μm nylon filter under positive pressure to remove flocculent gels and smaller precipitates. Finally, it was filtered through a 0.45 μm polyvinyl sulfone pleated filter under positive pressure to obtain the finished ink product.

[0069] Example 6

[0070] In the following order, 23.6 parts by weight of deionized water, 22 parts by weight of diethylene glycol, 20 parts by weight of ethylene glycol, 8 parts by weight of PEG400, 10 parts by weight of caprolactam, 12 parts by weight of ethylene glycol butyl ether, 0.5 parts by weight of surfactant Surfynol 465, 0.1 parts by weight of surfactant BYK3566, 1.0 part by weight of GXL, and 2.8 parts by weight of cationic blue 3 were placed in a container and stirred at a high speed of 600 rpm for 120 minutes. The mixture was then aged at 25°C for 24 hours to allow the ink components to completely dissolve and the system to reach equilibrium, with insoluble substances and unstable colloids precipitating out. After aging, the ink was first filtered through a 1.0 μm glass fiber filter under positive pressure to remove large particles and impurities, followed by a second filtration through a 0.65 μm nylon filter under positive pressure to remove flocculent gels and smaller precipitates. Finally, it was filtered through a 0.45 μm polyvinyl sulfone pleated filter under positive pressure to obtain the finished ink product.

[0071] Comparative Example 1

[0072] In sequence, 24.2 parts by weight of deionized water, 22 parts by weight of diethylene glycol, 20 parts by weight of ethylene glycol, 8 parts by weight of PEG400, 10 parts by weight of caprolactam, 12 parts by weight of ethylene glycol butyl ether, 1.0 part by weight of GXL, and 2.8 parts by weight of cationic blue 3 are placed in a container and stirred at a high speed of 600 rpm for 120 minutes. The mixture is then aged at 25°C for 24 hours to allow the ink components to completely dissolve and the system to reach equilibrium, resulting in the precipitation of insoluble substances and unstable colloids. After aging, the ink is first filtered under positive pressure using a 1.0 μm glass fiber filter to remove large particles and impurities, followed by a second filtration under positive pressure using a 0.65 μm nylon filter to remove flocculent gels and smaller precipitates. Finally, it is filtered under positive pressure using a 0.45 μm polyvinyl sulfone pleated filter to obtain the finished ink product.

[0073] Comparative Example 2

[0074] In a specific order, 24.55 parts by weight of deionized water, 22 parts by weight of diethylene glycol, 20 parts by weight of ethylene glycol, 8 parts by weight of PEG400, 10 parts by weight of caprolactam, 12 parts by weight of ethylene glycol butyl ether, 0.5 parts by weight of surfactant Surfynol 465, 0.15 parts by weight of surfactant Surfynol 104, 1.0 part by weight of GXL, and 2.8 parts by weight of cationic blue 3 were placed in a container and stirred at a high speed of 600 rpm for 120 minutes. The mixture was then aged at 25°C for 24 hours to allow the ink components to completely dissolve and the system to reach equilibrium, resulting in the precipitation of insoluble substances and unstable colloids. After aging, the ink was first filtered through a 1.0 μm glass fiber filter under positive pressure to remove large particles and impurities, followed by a second filtration through a 0.65 μm nylon filter under positive pressure to remove flocculent gels and smaller precipitates. Finally, it was filtered through a 0.45 μm polyvinyl sulfone pleated filter under positive pressure to obtain the finished ink product.

[0075] The table below shows the components (parts by mass) and test results of the inks used in Examples 1-4 and the Comparative Examples. Dynol 607, BYK3566, BYK094, Airase5100, Surfynol 440, Surfynol 465, Surfynol 104

[0076] Raw material type Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Deionized water 24.05 24.7 24.7 24.9 23.55 23.6 24.2 24.55 GXL 1 1 1 1 1 1 1 1 Surfynol 465 / / 0.5 0.15 0.5 0.5 / 0.5 BYK3566 0.15 0.5 / 0.15 0.15 0.1 / / Surfynol 104 / / / / / / / 0.15 Ethylene glycol 20 20 20 20 20 20 20 20 Diethylene glycol 22 22 22 22 22 22 22 22 PEG400 8 8 8 8 8 8 8 8 caprolactam 10 10 10 10 10 10 10 10 Ethylene glycol butyl ether 12 12 12 12 12 12 12 12 Cationic Dye Blue 3 2.8 2.8 2.8 2.8 2.8 2.8 2.8 2.8 stability OK OK OK OK OK OK OK OK SG1024 continuous printing 1 hour smoothness NG NG OK OK OK OK OK NG Standby in-situ moisturizing OK OK OK OK OK OK OK OK Angled spray, wire drawing NG NG NG NG OK NG NG NG Floating ink, accumulated ink OK OK NG OK OK NG NG NG

[0077] The test results show that when acetylenic diol wetting agents are combined with macromolecular polyether leveling agents, with a wetting agent:leveling agent ratio ranging from 2:1 to 4:1, the ink exhibits excellent flowability, stable storage, and eliminates various printing problems such as ink accumulation and drift caused by oblique spraying.

[0078] The amine and ether cosolvents used in the ink described in this application have a good stabilizing effect on the solubility and stability of cationic dyes in the ink system. The effect of surfactants used alone in the formulation is not as good as the effect of using them in combination. The combination of surfactants gives the ink better wettability and rheological properties, which allows the ink to maintain a good wet and dissolved state at the nozzle, ensuring that the ink has good printing performance and standby performance.

[0079] The ink described in this application exhibits excellent flowability, moisture retention, and stability, with no streaking or stringing. Printed fabrics display vibrant colors, and some thin-pile carpets can be washed without water. Acrylic fabrics achieve a lightfastness rating of 5-6. The ink described in this application also demonstrates good stability during storage, preventing issues such as dye leaching that could clog printheads or breakage.

[0080] Those skilled in the art should understand that the embodiments of this application described above are merely examples and do not limit the scope of this application. The advantages of this application have been fully and effectively implemented. The functions and structural principles of this application have been shown and explained in the embodiments, and any variations or modifications can be made to the implementation of this application without departing from the stated principles.

Claims

1. A high-viscosity digital printing cationic ink, characterized in that, The high-viscosity digital printing cationic ink, by weight percentage, comprises the following components: Cationic dyes 2.5-8.0% Solvent 20-60% Cosolvent 6-30% Surfactant 0.1%-1.0% High viscosity additive 1-3% pH adjuster 0.1-1% 0.1-1% of bactericide The remainder is deionized water.

2. The high-viscosity digital printing cationic ink according to claim 1, characterized in that, The ink viscosity range is 8-20 cps, with an optimal range of 12-15 cps.

3. The high-viscosity digital printing cationic ink according to claim 1, characterized in that, The surface tension of the ink ranges from 30 to 50 mN / m, with an optimal range of 35 to 45 mN / m.

4. The high-viscosity digital printing cationic ink according to claim 1, characterized in that, The pH range of the ink is 5.5-6.

5.

5. The high-viscosity digital printing cationic ink according to claim 1, characterized in that, The cationic dyes include at least one or three dyes selected from CI cationic yellow 28, CI cationic yellow 19, CI cationic yellow 51, CI cationic red 46, CI cationic blue 3, CI cationic blue 41, and CI cationic blue 159.

6. The high-viscosity digital printing cationic ink according to claim 1, characterized in that, The solvent is a mixture of at least two of the following: ethylene glycol, propylene glycol, diethylene glycol, glycerol, 1,2-pentanediol, 1,4-butanediol, dipropylene glycol, and 1,4-cyclohexyldiethanol.

7. The high-viscosity digital printing cationic ink according to claim 1, characterized in that, The co-solvent is a mixture of at least two of the following: propylene glycol monomethyl ether, N-methylformamide, N-methylpyrrolidone, 2-pyrrolidone, caprolactam, ethylene glycol butyl ether, and diethylene glycol monobutyl ether.

8. The high-viscosity digital printing cationic ink according to claim 1, characterized in that, The surfactant is one or a mixture of acetylenic diols, polyoxyethylene ethers, macromolecular polyether modified acrylates, Dynol 607, BYK3566, BYK094, Airase5100, Surfynol 440, Surfynol 465, Surfynol 104, and Aoke TL-J65A.

9. The high-viscosity digital printing cationic ink according to claim 1, characterized in that, It satisfies at least one of the following conditions: The surfactant used is an acetylenic diol wetting agent combined with a macromolecular polyether leveling agent; The high viscosity additive is one or a mixture of any two of the following: PPG200, PEG400, PEG6000, G300, polypropylene glycol, polyglycerol, ethyl cellulose, and polyvinylpyrrolidone. The bactericide is GXL; The pH adjuster is selected from at least one of Dow's AMP-95, triethanolamine, diethanolamine, and Tris base.

10. A method for preparing high-viscosity digital printing cationic ink based on any one of claims 1-9, characterized in that, Includes the following steps: S01, according to the preset ratio of high viscosity digital printing cationic ink, the cationic raw powder is mixed and dissolved with deionized water, the pH is adjusted to acidic, then alkali is added to precipitate, and filtered to obtain refined cationic raw material; S102, turn on the mixer, add water, preferably add solvent, cosolvent, surfactant, bactericide and pH adjuster while stirring at a speed of 400-600 rpm, stir evenly, preferably for 20-30 min, add the cationic raw material obtained in step S101, continue to stir and mix at a speed of 600-800 rpm, stirring for 120-240 min; S103, after feeding, test the viscosity and surface tension. The optimal viscosity range is 12-15.0 cps, and the optimal surface tension range is 40-45 mN / m. Adjust the pH to 5.5-6.5.