Formula and preparation method of digital coating direct-injection ink

Abstract

The invention relates to the technical field of ink coatings, and provides a digital coating direct-jet ink formula which comprises the following components in percentage by weight: 20%-40% of nano white pre-dispersed color paste, 15%-35% of high-elastic polyurethane emulsion, 20%-35% of propylene glycol, 5%-15% of a wetting dispersant and 0.1%-1% of a high-temperature-resistant environment-friendly bactericide. The solid content of the nano white pre-dispersed color paste is 30%-40%, the particle size of the nano white pre-dispersed color paste is 50-200 nm, the solid content of the high-elastic polyurethane emulsion is 20%-30%, and the elastic modulus of the high-elastic polyurethane emulsion is 5-15 MPa. The nano white pre-dispersed color paste in the formula is small in particle size and uniform in distribution, the high-elastic polyurethane emulsion is matched, the adhesive force and elasticity are good, the propylene glycol and the wetting dispersant improve the fluidity and stability, the bactericide prolongs the storage period, the manufacturing method combines mechanical stirring and ultrasonic dispersion, parameters are strictly controlled, performance is optimized, the precise control requirement of a spray head is met, and the production cost is reduced. The finished product ink is high in stability, fine in printing color and high in definition, and meets the high-precision requirement of high-end digital printing.

Description

Technical Field

[0001] The present invention relates to the technical field of ink and coatings, and in particular to a formulation and a production method of a direct-jet ink for digital coatings. Background Art

[0002] Digital direct-injection inks are water-based pigment inks used in digital inkjet printing equipment. Composed of pigment, resin, and solvent, they are precisely sprayed onto fabrics like cotton and linen through a nozzle. The resin cross-links with the fibers, resulting in vibrant colors, excellent stability, and environmental friendliness. They are widely used in clothing, home textiles, and other fields, meeting the needs of personalized, small-batch production.

[0003] Existing ink formulas often suffer from poor nano-colorant dispersion and mismatch of emulsion elastic modulus, resulting in insufficient adhesion and poor flexibility of the ink film after printing, especially prone to cracking and falling off on bent or stretched substrates. At the same time, traditional inks lack high-efficiency and high-temperature resistant bactericides, and are prone to breeding microorganisms during storage, affecting the shelf life and performance of the ink. In addition, insufficient stirring and dispersion in the production process and imperfect filtration and detection processes often cause uneven ink particle size distribution and unstable viscosity, leading to nozzle blockage or print color difference, which makes it difficult to meet the needs of modern digital printing for high speed, high precision, and multi-substrate adaptation. There is an urgent need for a new direct-jet ink formula and preparation method with optimized performance and controllable process. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention provides a digital coating direct-jet ink formulation and production method, which solves the problems of mechanical properties and uneven particle size distribution of spray ink in the existing technology.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: a digital paint direct-jet ink formula and production method, comprising the following components by weight percentage: 20%-40% nano white pre-dispersed color paste, 15%-35% high-elastic polyurethane emulsion, 20%-35% propylene glycol, 5%-15% wetting dispersant, 0.1%-1% high-temperature resistant environmentally friendly fungicide, the solid content of the nano white pre-dispersed color paste is 30%-40%, the particle size is 50-200nm, the solid content of the high-elastic polyurethane emulsion is 20%-30%, and its elastic modulus is 5-15MPa.

[0006] Preferably, the composition includes the following components by weight percentage: 35% of nano white pre-dispersed color paste, 25% of high elastic polyurethane emulsion, 29.6% of propylene glycol, 10% of wetting and dispersing agent, and 0.4% of high temperature resistant and environmentally friendly fungicide.

[0007] Preferably, the wetting and dispersing agent is selected from one or more combinations of polycarboxylate dispersants, polyacrylate dispersants, and alkylphenol polyoxyethylene ether dispersants.

[0008] Preferably, the high-temperature resistant and environmentally friendly fungicide is selected from one or more combinations of isothiazolinone fungicides, benzisothiazolinone fungicides, and pyrithione zinc fungicides.

[0009] Preferably, the invention further comprises a rheology regulator accounting for 0.5% to 3% of the total weight, wherein the rheology regulator is one of hydroxyethyl cellulose and polyacrylate or a mixture of the two.

[0010] Preferably, the ink further comprises a pH regulator accounting for 0.1%-2% of the total weight, wherein the pH regulator is one of ammonia water and triethanolamine or a mixture of the two, and is used to adjust the pH value of the ink to 7.5-9.0.

[0011] Preferably, the method for preparing the digital coating direct-jet ink formulation comprises the following steps:

[0012] S1 premixing step: propylene glycol, highly elastic polyurethane emulsion and wetting dispersant were added to the reaction vessel and stirred at a stirring speed of 200-800r / min for 10-30min to obtain a premix;

[0013] S2 colorant adding step: adding nano white pre-dispersed colorant to the premixed solution, continuing to stir at a stirring speed of 300-1000r / min for 20-40min to fully mix the colorant and premixed solution;

[0014] S3 fungicide and other additives adding step: adding a high temperature resistant environmentally friendly fungicide, as well as the addition of a rheology modifier and a pH adjuster as needed, stirring at a stirring speed of 100-600r / min under conditions of 10-20min;

[0015] S4. Filtration step: filtering the mixed ink through a filter with a pore size of 1-5 μm to obtain the digital paint direct injection ink.

[0016] Preferably, during the premixing step and the color paste adding step, the temperature in the reaction container is controlled at 20-40°C.

[0017] Preferably, after the filtration step, a detection step is also included, in which the viscosity, pH value, particle size distribution and stability of the filtered ink are tested, wherein the viscosity is tested using a rotational viscometer at 25°C, and the viscosity range is controlled at 5-20mPa·s. The particle size distribution is tested using a laser particle size analyzer to ensure that the particle size distribution of the nano white pre-dispersed color paste is within the range of 50-200nm.

[0018] Preferably, the stirring process adopts a combination of mechanical stirring and ultrasonic dispersion. During the stirring process after adding the nano white pre-dispersed color paste, the ultrasonic dispersion device is turned on, the ultrasonic power is 100-500W, and the dispersion time is 10-30min.

[0019] The present invention provides a formula and production method for direct-jet ink for digital coatings. It has the following beneficial effects:

[0020] 1. The nano white pre-dispersed color paste in the formula of the present invention has a small and evenly distributed particle size. It is combined with a high-elastic polyurethane emulsion to give the ink good adhesion and elasticity. It can firmly adhere to the surfaces of various materials and meet the printing requirements of digital direct injection on different substrates. Propylene glycol and wetting and dispersing agents improve the fluidity and dispersion stability of the ink. The high-temperature resistant and environmentally friendly fungicide extends the ink storage period, ensuring stable printing quality and making it suitable for industrial large-scale production.

[0021] 2. The production method of the present invention combines mechanical stirring with ultrasonic dispersion to ensure that the color paste is fully dispersed and avoid agglomeration. The filtration and detection steps strictly control the ink viscosity, particle size and other parameters to prevent nozzle clogging and improve printing smoothness. Rheology regulators and pH regulators are added to optimize the ink rheological properties and pH value to meet the requirements of precise nozzle control. The finished ink has strong stability, delicate print colors and high clarity, meeting the high-precision requirements of high-end digital printing. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] Example 1:

[0024] An embodiment of the present invention provides a digital coating direct-jet ink formula, including the following components by weight percentage: 35% nano-white pre-dispersed color paste, 25% high-elastic polyurethane emulsion, 29.6% propylene glycol, 10% wetting and dispersing agent, and 0.4% high-temperature resistant and environmentally friendly fungicide, wherein the nano-white pre-dispersed color paste has a solid content of 35% and a particle size of 120nm; the high-elastic polyurethane emulsion has a solid content of 25% and an elastic modulus of 10MPa; the wetting and dispersing agent is a polycarboxylate dispersant; and the high-temperature resistant and environmentally friendly fungicide is an isothiazolinone fungicide.

[0025] Preparation method:

[0026] S1 premixing step: propylene glycol, highly elastic polyurethane emulsion and wetting dispersant were added to the reaction vessel and stirred at a stirring speed of 500r / min for 20min to obtain a premixed solution. The temperature in the reaction vessel was controlled at 30°C.

[0027] S2 colorant addition step: Add nano white pre-dispersed colorant to the premixed solution, continue stirring at a stirring speed of 600r / min for 30min to fully mix the colorant and premixed solution;

[0028] S3. Addition step of fungicide and other additives: Add high temperature resistant environmentally friendly fungicide and stir at a stirring speed of 300r / min for 15min;

[0029] S4. Filtration step: The mixed ink is filtered through a filter with a pore size of 3 μm to obtain a digital paint direct injection ink;

[0030] S5. Testing steps: Test the viscosity, pH value, particle size distribution, and stability of the filtered ink. Use a rotational viscometer to test the viscosity at 25°C and ensure that it is within the range of 5-20 mPa·s. Use a laser particle size analyzer to test the particle size distribution and ensure that the particle size distribution of the nano white pre-dispersed color paste is within the range of 50-200 nm.

[0031] Example 2:

[0032] An embodiment of the present invention provides a digital coating direct-jet ink formula, including the following components in weight percentage: 25% nano white pre-dispersed color paste, 30% high-elastic polyurethane emulsion, 22% propylene glycol, 15% wetting and dispersing agent, 0.5% high-temperature resistant and environmentally friendly fungicide, 2.5% rheology regulator, and 5% pH regulator. The nano white pre-dispersed color paste has a solid content of 32% and a particle size of 150 nm; the high-elastic polyurethane emulsion has a solid content of 28% and an elastic modulus of 8 MPa; the wetting and dispersing agent is a combination of a polyacrylate dispersant and an alkylphenol polyoxyethylene ether dispersant; the high-temperature resistant and environmentally friendly fungicide is a combination of a benzisothiazolinone fungicide and a pyrithione zinc fungicide; the rheology regulator is hydroxyethyl cellulose; and the pH regulator is ammonia water.

[0033] Preparation method:

[0034] S1 premixing step: propylene glycol, highly elastic polyurethane emulsion and wetting dispersant were added to the reaction vessel and stirred at a stirring speed of 400r / min for 25min to obtain a premixed solution. The temperature in the reaction vessel was controlled at 25°C.

[0035] S2 colorant adding step: adding nano white pre-dispersed colorant to the premixed liquid, continue stirring at a stirring speed of 700r / min for 25min, while turning on the ultrasonic dispersion device, the ultrasonic power is 300W, the dispersion time is 20min, so that the colorant and premixed liquid are fully mixed;

[0036] S3. Addition step of fungicide and other additives: Add high temperature resistant environmentally friendly fungicide, rheology modifier and pH adjuster, and stir at a stirring speed of 200r / min for 18min;

[0037] S4. Filtration step: The mixed ink is filtered through a filter with a pore size of 2 μm to obtain a digital paint direct injection ink;

[0038] S5. Testing steps: Test the viscosity, pH value, particle size distribution, and stability of the filtered ink. Use a rotational viscometer to test the viscosity at 25°C and ensure that it is within the range of 5-20 mPa·s. Use a laser particle size analyzer to test the particle size distribution and ensure that the particle size distribution of the nano white pre-dispersed color paste is within the range of 50-200 nm.

[0039] Example 3:

[0040] This embodiment of the present invention provides a direct-jet ink formulation for digital coatings, comprising the following components, by weight: 40% nano-white pre-dispersed colorant, 15% high-elastic polyurethane emulsion, 25% propylene glycol, 14% wetting and dispersing agent, 1% high-temperature resistant and environmentally friendly fungicide, 3% rheology modifier, and 2% pH adjuster. The nano-white pre-dispersed colorant has a solids content of 38% and a particle size of 180 nm; the high-elastic polyurethane emulsion has a solids content of 22% and an elastic modulus of 12 MPa; the wetting and dispersing agent is a combination of a polycarboxylate dispersant and a polyacrylate dispersant; the high-temperature resistant and environmentally friendly fungicide is a combination of an isothiazolinone fungicide and a benzisothiazolinone fungicide; the rheology modifier is polyacrylate; and the pH adjuster is triethanolamine.

[0041] Preparation method:

[0042] S1 premixing step: propylene glycol, highly elastic polyurethane emulsion and wetting dispersant were added to the reaction vessel and stirred at a stirring speed of 600r / min for 15min to obtain a premixed solution. The temperature in the reaction vessel was controlled at 35°C.

[0043] S2 colorant addition step: Nano White pre-dispersed colorant was added to the premixed solution, and stirring was continued at a stirring speed of 800r / min for 22min. At the same time, the ultrasonic dispersion device was turned on, the ultrasonic power was 400W, and the dispersion time was 18min, so that the colorant and the premixed solution were fully mixed;

[0044] S3. Addition step of fungicide and other additives: Add high temperature resistant environmentally friendly fungicide, rheology modifier and pH adjuster, and stir at a stirring speed of 400r / min for 12min;

[0045] S4. Filtration step: The mixed ink is filtered through a filter with a pore size of 4 μm to obtain a digital paint direct injection ink;

[0046] S5. Testing steps: Test the viscosity, pH value, particle size distribution, and stability of the filtered ink. Use a rotational viscometer to test the viscosity at 25°C and ensure that it is within the range of 5-20 mPa·s. Use a laser particle size analyzer to test the particle size distribution and ensure that the particle size distribution of the nano white pre-dispersed color paste is within the range of 50-200 nm.

[0047] Comparative Example:

[0048] This comparative example provides a direct-jet ink formulation for digital coatings, comprising the following components, by weight: 15% nano-white pre-dispersed colorant, 35% conventional polyurethane emulsion, 30% propylene glycol, 18% conventional dispersant, 1.5% conventional fungicide, and 0.5% pH adjuster. The nano-white pre-dispersed colorant has a solids content of 30% and a particle size of 250 nm; the conventional polyurethane emulsion has a solids content of 30% and an elastic modulus of 5 MPa; the conventional dispersant is lignin sulfonate; the conventional fungicide is a benzoic acid-based fungicide; and the pH adjuster is sodium hydroxide.

[0049] Preparation method:

[0050] S1 premixing step: propylene glycol, ordinary polyurethane emulsion and traditional dispersant were added to the reaction vessel and stirred at a stirring speed of 400r / min for 20min to obtain a premixed solution. The temperature in the reaction vessel was controlled at 30°C.

[0051] S2 colorant addition step: Add nano white pre-dispersed colorant to the premixed solution and continue stirring at a stirring speed of 500r / min for 25min;

[0052] S3. Addition step of fungicide and other additives: Add common fungicide and pH adjuster and stir at a stirring speed of 300r / min for 15min;

[0053] S4. Filtration step: The mixed ink is filtered through a filter with a pore size of 5 μm to obtain a digital paint direct injection ink;

[0054] S5. Testing steps: The filtered ink is tested for viscosity, pH value, particle size distribution, and stability. The viscosity is tested at 25°C using a rotational viscometer; the particle size distribution is tested using a laser particle size analyzer.

[0055] In order to directly compare the performance differences of the inks prepared in the examples and the comparative examples, the performance parameter data shown in the following table were obtained through systematic detection and testing:

[0056]

[0057] In summary, the examples utilize nano-white pre-dispersed color paste, high-elastic polyurethane emulsion, and other raw materials, along with specific dispersants and fungicides, and undergo precise stirring, dispersion, filtration, and testing. The comparative examples utilize standard raw materials and traditional additives. Performance testing reveals that the inks in the examples exhibit moderate viscosity, a reasonable particle size distribution, a stable pH value, exhibit no precipitation or delamination after six months of storage, exhibit high film hardness after drying, and exhibit excellent water washability. The comparative examples, on the other hand, exhibit inferior particle size distribution, storage stability, and water washability, demonstrating the superiority of the formulation and process of the examples.

[0058] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. Digital coating direct injection ink formula, characterized by: The invention comprises the following components by weight percentage: 20%-40% of nano white pre-dispersed color paste, 15%-35% of high elastic polyurethane emulsion, 20%-35% of propylene glycol, 5%-15% of wetting and dispersing agent, and 0.1%-1% of high temperature resistant and environmentally friendly fungicide. The solid content of the nano white pre-dispersed color paste is 30%-40%, and the particle size is 50-200nm. The solid content of the high elastic polyurethane emulsion is 20%-30%, and its elastic modulus is 5-15MPa.

2. The digital coating direct-jet ink formulation according to claim 1, characterized in that: The invention comprises the following components in percentage by weight: 35% of nano white pre-dispersed color paste, 25% of high elastic polyurethane emulsion, 29.6% of propylene glycol, 10% of wetting and dispersing agent, and 0.4% of high temperature resistant and environmentally friendly fungicide.

3. The digital coating direct-jet ink formulation according to claim 1, characterized in that: The wetting dispersant is selected from one or more combinations of polycarboxylate dispersants, polyacrylate dispersants, and alkylphenol polyoxyethylene ether dispersants.

4. The digital coating direct-jet ink formulation according to claim 1, characterized in that: The high-temperature resistant and environmentally friendly fungicide is selected from one or more combinations of isothiazolinone fungicides, benzisothiazolinone fungicides, and pyrithione zinc fungicides.

5. The digital coating direct-jet ink formulation according to claim 1, characterized in that: The invention also includes a rheology regulator accounting for 0.5% to 3% of the total weight, wherein the rheology regulator is one of hydroxyethyl cellulose and polyacrylate or a mixture of the two.

6. The digital coating direct-jet ink formulation according to claim 1, characterized in that: The invention also includes a pH regulator accounting for 0.1%-2% of the total weight. The pH regulator is one of ammonia water and triethanolamine or a mixture of the two, and is used to adjust the pH value of the ink to 7.5-9.

0.

7. The method for preparing a digital coating direct-jet ink formulation according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1 premixing step: propylene glycol, highly elastic polyurethane emulsion and wetting dispersant were added to the reaction vessel and stirred at a stirring speed of 200-800r / min for 10-30min to obtain a premix; S2 colorant adding step: adding nano white pre-dispersed colorant to the premixed solution, continuing to stir at a stirring speed of 300-1000r / min for 20-40min to fully mix the colorant and premixed solution; S3 fungicide and other additives adding step: adding a high temperature resistant environmentally friendly fungicide, as well as the addition of a rheology modifier and a pH adjuster as needed, stirring at a stirring speed of 100-600r / min under conditions of 10-20min; S4. Filtration step: filtering the mixed ink through a filter with a pore size of 1-5 μm to obtain the digital paint direct injection ink.

8. The method for preparing a digital coating direct-jet ink formulation according to claim 7, wherein: During the premixing step and the color paste adding step, the temperature in the reaction vessel is controlled at 20-40°C.

9. The method for preparing a digital coating direct-jet ink formulation according to claim 7, wherein: After the filtration step, a testing step is also included to test the viscosity, pH value, particle size distribution and stability of the filtered ink. The viscosity is tested using a rotational viscometer at 25°C, and the viscosity range is controlled at 5-20mPa·s. The particle size distribution is tested using a laser particle size analyzer to ensure that the particle size distribution of the nano white pre-dispersed color paste is within the range of 50-200nm.

10. The method for preparing a digital coating direct-jet ink formulation according to claim 7, wherein: The stirring process adopts a combination of mechanical stirring and ultrasonic dispersion. During the stirring process after adding the nano white pre-dispersed color paste, the ultrasonic dispersion device is turned on, the ultrasonic power is 100-500W, and the dispersion time is 10-30min.

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