Self-dispersing pigment nano color paste for digital ink-jet printing and preparation method of self-dispersing pigment nano color paste

Abstract

The invention relates to a self-dispersing pigment nano color paste for digital ink-jet printing and a preparation method thereof, and the self-dispersing pigment nano color paste is prepared from the following raw materials: 15-25 parts of carbon black, 10-17 parts of a surfactant, 8-13 parts of a dispersant, 13-30 parts of ethylene glycol, 3-5 parts of a stabilizer, 3-8 parts of a pH value regulator and 20-35 parts of deionized water. Methylisocyanate modified styrene-acrylic resin is used as a dispersing agent to act together with a surfactant, so that the uniform dispersion performance of pigment in the nano color paste is improved, the risk of blockage is reduced, sodium benzoate modified lauryl sodium sulfate is used as a stabilizer, the liquidity and spraying stability of the nano color paste in a spray head are enhanced, and the spraying effect is improved. In the system provided by the invention, ethylene glycol is used as a solvent, 2-aminopropanol, triethanolamine, sodium carbonate, sodium hexametaphosphate and sodium polyacrylate are mixed to be used as a pH value regulator, and deionized water is used for further enhancing the compatibility of the dye.

Description

Technical Field

[0001] The invention relates to the technical field of self-dispersible pigment nano-color paste, and in particular to a self-dispersible pigment nano-color paste and a preparation method thereof. Background Art

[0002] Digital inkjet printing is a printing technology that realizes printing operations by precisely ejecting ink droplets. It uses electronic text as a carrier and transmits it to related equipment through the network for direct printing. There is no need for printing plates in the printing production process, and the information is variable. While simplifying the printing process, it also improves the flexibility of the traditional printing industry, covering a variety of technical fields such as printing, electronics, computers, networks, and communications. In the process of digital inkjet printing, character inkjet colorants play a key role, and inkjet printing places higher requirements on the dispersion and stability of colorants.

[0003] Existing self-dispersible pigment nano-color pastes use finely ground nano-pigment particles, which can significantly improve the image quality of digital inkjet printing. When used with special paper, they can achieve image quality close to that of offset printing. However, self-dispersible nano-color pastes may still have stability problems after long-term storage. The color paste particles are also prone to agglomeration and clogging the inkjet printer nozzles due to their low dispersibility.

[0004] For example, the invention patent with application number 202110797695.0 provides a PCB character inkjet nano-colorant and its preparation method and application. Through the synergistic effect of titanium dioxide and aluminum hydroxide, the adhesion of acrylate monomers is improved, and the stability and anti-settling property of nano-colorant is improved. However, a serious problem in this technology is that the pigment dispersion is not improved. For example, the patent with application number 201711412364.0 discloses a method for preparing water-based resin pigments for inkjet printing. The technical solution uses the invented water-based resin to improve the color fastness of the colorant, but does not solve the problem of agglomeration of colorant particles.

[0005] Based on this, there is an urgent need for a self-dispersible pigment nano-color paste with strong stability to avoid the defects in the color paste performance affecting the printing quality. Summary of the invention

[0006] The purpose of the present invention is to provide a self-dispersible pigment nano-color paste with high dispersibility and strong stability and a preparation method thereof.

[0007] In order to achieve the above-mentioned purpose, the present invention provides the following technical scheme: a self-dispersible pigment nano-color paste for digital inkjet printing, which comprises at least the following components by mass: 15-25 parts of carbon black, 10-17 parts of surfactant, 8-13 parts of dispersant, 13-30 parts of ethylene glycol, 3-5 parts of stabilizer, 3-8 parts of pH regulator, and 20-35 parts of deionized water.

[0008] As a preferred technical solution, the surfactant is at least one of glycerol random polyether GPE-3000, sodium salt of sulfonated succinic acid dioctanoate, fatty alcohol polyoxyethylene ether 20, fatty alcohol polyoxyethylene ether, polyoxyethylene sorbitan fatty acid ester, nonylphenol polyoxyethylene ether NP-10, and polyoxyethylene glycerol ether.

[0009] As a preferred technical solution, the dispersant is methyl isocyanate-modified styrene-acrylic resin.

[0010] As a preferred technical solution, the method for modifying styrene-acrylic resin with methyl isocyanate comprises at least the following steps: (1) Add methyl isocyanate and diethylene glycol dimethyl ether into a reactor and heat it to 110°C; then simultaneously add acrylic acid, methyl methacrylate, styrene monomer and benzoyl peroxide dropwise into the reactor, maintain the temperature at 110°C and stir for 10 hours to obtain a polymer solution; (2) Add deionized water to the polymer solution obtained in step 1), stir to produce precipitation, let it stand for 2-5 hours, filter with suction, and dry the filter cake in a vacuum oven at 80°C for 5 hours; then increase the temperature to 120°C and vacuum dry for 3 hours until the resin foams to obtain styrene-acrylic resin.

[0011] As a preferred technical solution, the mass ratio of methyl isocyanate, diethylene glycol dimethyl ether, acrylic acid, methyl methacrylate, styrene monomer, and benzoyl peroxide is 7:5:9:2:13:3.

[0012] As a preferred technical solution, the stabilizer is sodium benzoate-modified sodium dodecyl sulfate.

[0013] As a preferred technical solution, the preparation method of the sodium benzoate modified sodium dodecyl sulfate stabilizer comprises at least the following steps: (1) Heat 20 parts of gelatin solution to 55°C, add 7 parts of sodium benzoate, and stir evenly; (2) Cool to 35°C, add 2 parts of citric acid, and stir continuously for 2 hours using a high-speed stirrer to obtain dispersion A; (3) Heat dispersion A to 70°C, add 3 parts of sodium lauryl sulfate, and stir evenly.

[0014] As a preferred technical solution, the mass fraction of the gelatin solution is 5%.

[0015] As a preferred technical solution, the pH regulator is prepared by 2-aminopropanol, triethanolamine, sodium carbonate, and sodium hexametaphosphate, and the mass ratio of the 2-aminopropanol, triethanolamine, sodium carbonate, and sodium hexametaphosphate is 3:1:5:2.

[0016] As a preferred technical solution, the method for preparing the self-dispersible pigment nano-color paste comprises at least the following steps: (1) Weigh the carbon black and add it into the ball mill. Adjust the speed of the ball mill to 600r / s and grind D95 ​​< 0.2μm; (2) The ground carbon black, surfactant, dispersant, ethylene glycol, stabilizer, and deionized water are weighed and placed in a mixing container to obtain a mixed solution; (3) The mixed solution is heated to 65°C, the pH adjuster is weighed and added to the mixed solution, the ball mill is started, the speed of the ball mill is adjusted to 600 r / s, and the components are ground and mixed uniformly by the ball mill to obtain a uniform mixture.

[0017] Beneficial Effects The present invention provides a self-dispersible pigment nano-color paste and a preparation method thereof. The present invention compound multiple components to synergistically enhance the effect. By using methyl isocyanate-modified styrene-acrylic resin as a dispersant to act together with a surfactant, the uniform dispersion performance of the pigment in the nano-color paste is improved, the risk of clogging is reduced, sodium benzoate-modified sodium dodecyl sulfate is used as a stabilizer, the flowability and injection stability of the nano-color paste in the nozzle are enhanced, and the inventor uses ethylene glycol as a solvent in the system of the present invention, 2-aminopropanol, triethanolamine, sodium carbonate, sodium hexametaphosphate, and sodium polyacrylate are mixed as a pH value regulator, and deionized water is used to further enhance the dye compatibility. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Example 1 A self-dispersible pigment nano-color paste in this embodiment includes the following components in parts by weight: 20 parts of carbon black, 14 parts of surfactant, 10 parts of dispersant, 23 parts of ethylene glycol, 3 parts of stabilizer, 5 parts of pH adjuster, and 30 parts of deionized water.

[0020] The surfactant is fatty alcohol polyoxyethylene ether, with a cloud point of ≥75°C (1wt% aqueous solution), an HLB value of 13.3, purchased from Xingtai Xinlanxing Technology Co., Ltd. The dispersant is methyl isocyanate modified styrene-acrylic resin, the stabilizer is sodium benzoate modified sodium dodecyl sulfate, the pH adjuster is prepared from 2-aminopropanol, triethanolamine, sodium carbonate, and sodium hexametaphosphate, and the mass ratio of 2-aminopropanol, triethanolamine, sodium carbonate, and sodium hexametaphosphate is 3:1:5:2.

[0021] The method for modifying styrene-acrylic resin with methyl isocyanate comprises the following steps: (1) Add methyl isocyanate and diethylene glycol dimethyl ether into a reactor and heat it to 110°C; then simultaneously add acrylic acid, methyl methacrylate, styrene monomer and benzoyl peroxide dropwise into the reactor, maintain the temperature at 110°C and stir for 10 hours to obtain a polymer solution; (2) Add deionized water to the polymer solution obtained in step 1), stir to produce precipitation, let it stand for 3 hours, filter with suction, and dry the filter cake in a vacuum oven at 80°C for 5 hours; then increase the temperature to 120°C and vacuum dry for 3 hours until the resin foams, thereby obtaining a styrene-acrylic resin.

[0022] The mass ratio of methyl isocyanate, diethylene glycol dimethyl ether, acrylic acid, methyl methacrylate, styrene monomer and benzoyl peroxide is 7:5:9:2:13:3.

[0023] The preparation method of the sodium benzoate modified sodium dodecyl sulfate stabilizer comprises the following steps, calculated by weight: (1) Heat 20 parts of gelatin solution (5 wt% aqueous solution) to 55°C, add 7 parts of sodium benzoate, and stir evenly; (2) Cool to 35°C, add 2 parts of citric acid, and stir continuously for 2 hours using a high-speed stirrer to obtain dispersion A; (3) Heat dispersion A to 70°C, add 3 parts of sodium lauryl sulfate, and stir evenly.

[0024] A method for preparing the above self-dispersible pigment nano-color paste comprises the following steps: (1) Weigh the carbon black and add it into the ball mill. Adjust the speed of the ball mill to 600r / s and grind D95 ​​< 0.2μm; (2) The ground carbon black, surfactant, dispersant, ethylene glycol, stabilizer, and deionized water are weighed and placed in a mixing container to obtain a mixed solution; (3) Heat the mixed solution to 65°C, weigh the pH adjuster and add it to the mixed solution, start the ball mill, adjust the speed of the ball mill to 600r / s, grind and mix the components evenly through the ball mill to obtain a uniform mixture.

[0025] Example 2 A self-dispersible pigment nano-color paste in this embodiment includes the following components by weight: 25 parts of carbon black, 15 parts of surfactant, 11 parts of dispersant, 28 parts of ethylene glycol, 5 parts of stabilizer, 7 parts of pH adjuster, and 30 parts of deionized water. The surfactant is fatty alcohol polyoxyethylene ether with a turbidity point of ≥75°C (1wt% aqueous solution) and an HLB value of 13.3, which is purchased from Xingtai Xinlanxing Technology Co., Ltd. The dispersant is methyl isocyanate-modified styrene-acrylic resin, the stabilizer is sodium benzoate-modified sodium dodecyl sulfate, and the pH adjuster is prepared from 2-aminopropanol, triethanolamine, sodium carbonate, and sodium hexametaphosphate. The mass ratio of 2-aminopropanol, triethanolamine, sodium carbonate, and sodium hexametaphosphate is 3:1:5:2.

[0026] The method for modifying styrene-acrylic resin with methyl isocyanate comprises the following steps: (1) Add methyl isocyanate and diethylene glycol dimethyl ether into a reactor and heat it to 110°C; then simultaneously add acrylic acid, methyl methacrylate, styrene monomer and benzoyl peroxide dropwise into the reactor, maintain the temperature at 110°C and stir for 10 hours to obtain a polymer solution; (2) Add deionized water to the polymer solution obtained in step 1), stir to produce precipitation, let it stand for 3 hours, filter with suction, and dry the filter cake in a vacuum oven at 80°C for 5 hours; then increase the temperature to 120°C and vacuum dry for 3 hours until the resin foams, thereby obtaining a styrene-acrylic resin.

[0027] The mass ratio of methyl isocyanate, diethylene glycol dimethyl ether, acrylic acid, methyl methacrylate, styrene monomer and benzoyl peroxide is 7:5:9:2:13:3.

[0028] The method for modifying a sodium dodecyl sulfate stabilizer with sodium benzoate comprises the following steps, calculated by weight: (1) Heat 20 parts of gelatin solution (5 wt% aqueous solution) to 55°C, add 7 parts of sodium benzoate, and stir evenly; (2) Cool to 35°C, add 2 parts of citric acid, and stir continuously for 2 hours using a high-speed stirrer to obtain dispersion A; (3) Heat dispersion A to 70°C, add 3 parts of sodium lauryl sulfate, and stir evenly.

[0029] A method for preparing the above self-dispersible pigment nano-color paste comprises the following steps: (1) Weigh the carbon black and add it into the ball mill. Adjust the speed of the ball mill to 600r / s and grind D95 ​​< 0.2μm; (2) The ground carbon black, surfactant, dispersant, ethylene glycol, stabilizer, and deionized water are weighed and placed in a mixing container to obtain a mixed solution; (3) Heat the mixed solution to 65°C, weigh the pH adjuster and add it to the mixed solution, start the ball mill, adjust the speed of the ball mill to 600r / s, grind and mix the components evenly through the ball mill to obtain a uniform mixture.

[0030] Comparative Example 1 The difference between this comparative example and Example 1 is that no dispersant and stabilizer are added, and the other technical features are the same as those in Example 1.

[0031] Comparative Example 2 The difference between this comparative example and Example 1 is that the dispersant is styrene-acrylic resin, the stabilizer is sodium lauryl acid, and the other technical features are the same as those in Example 1.

[0032] Comparative Example 3 The difference between this comparative example and Example 1 is that the dispersant is styrene-acrylic resin, and no pH adjuster is added. The other technical features are the same as those in Example 1.

[0033] Comparative Example 4 The difference between this comparative example and Example 1 is that the stabilizer is sodium dodecyl salt and no pH adjuster is added. The other technical features are the same as those in Example 1.

[0034] Comparative Example 5 The difference between this comparative example and Example 1 is that the dispersant is methyl isocyanate and the stabilizer is sodium dodecyl salt. The other technical features are the same as those in Example 1.

[0035] Comparative Example 6 The difference between this comparative example and Example 1 is that no dispersant and pH adjuster are added, and the other technical features are the same as those in Example 1.

[0036] Performance Testing The color pastes prepared in Examples 1-2 and Comparative Examples 1-6 were subjected to normal temperature viscosity and high temperature aging for 30 days properties analysis using a liquid titration viscometer.

[0037] Table 1 Viscosity performance test

[0038] As shown in Table 1, it can be seen that the nano color paste obtained in Example 1-2 is aged at 180° C. for 30 days. After aging, the test shows that the nano color paste does not sink to the bottom and the viscosity change is less than 5%, indicating good properties.

[0039] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A self-dispersible pigment nano-color paste for digital inkjet printing, characterized in that: The invention comprises at least the following components by weight: 15-25 parts of carbon black, 10-17 parts of surfactant, 8-13 parts of dispersant, 13-30 parts of ethylene glycol, 3-5 parts of stabilizer, 3-8 parts of pH value regulator and 20-35 parts of deionized water.

2. The self-dispersible pigment nano-paste according to claim 1, characterized in that: The surfactant is at least one of glycerol random polyether GPE-3000, sulfonated succinic acid dioctanoate sodium salt, fatty alcohol polyoxyethylene ether 20, fatty alcohol polyoxyethylene ether, polyoxyethylene sorbitol fatty acid ester, nonylphenol polyoxyethylene ether NP-10, and polyoxyethylene glycerol ether.

3. The self-dispersible pigment nano-paste according to claim 2, characterized in that: The dispersant is methyl isocyanate modified styrene-acrylic resin.

4. The self-dispersible pigment nano-paste according to claim 3, characterized in that: The method for modifying styrene-acrylic resin with methyl isocyanate comprises at least the following steps: Methyl isocyanate and diethylene glycol dimethyl ether were added into the reactor, and the temperature was raised to 110° C.; acrylic acid, methyl methacrylate, styrene monomer, and benzoyl peroxide were then added dropwise into the reactor at the same time, and the temperature was maintained at 110° C. and stirred for 10 hours to obtain a polymer solution; Deionized water is added to the polymer solution obtained in step 1), stirred to produce precipitation, allowed to stand for 2-5 hours, filtered, and the filter cake is dried in a vacuum oven at 80°C for 5 hours; then the temperature is raised to 120°C and vacuum dried for 3 hours until the resin is foamed to obtain styrene-acrylic resin.

5. The self-dispersible pigment nano-paste according to claim 4, characterized in that: The mass ratio of methyl isocyanate, diethylene glycol dimethyl ether, acrylic acid, methyl methacrylate, styrene monomer and benzoyl peroxide is 7:5:9:2:13:

3.

6. The self-dispersible pigment nano-paste according to claim 1, characterized in that: The stabilizer is sodium benzoate modified sodium dodecyl sulfate.

7. The self-dispersible pigment nano-paste according to claim 6, characterized in that: The preparation method of the sodium benzoate modified sodium dodecyl sulfate stabilizer comprises at least the following steps: (1) Heat 20 parts of gelatin solution to 55°C, add 7 parts of sodium benzoate, and stir evenly; (2) Cool to 35°C, add 2 parts of citric acid, and stir continuously for 2 hours using a high-speed stirrer to obtain dispersion A; (3) Heat dispersion A to 70°C, add 3 parts of sodium lauryl sulfate, and stir evenly.

8. The self-dispersible pigment nano-paste according to claim 7, characterized in that: The mass fraction of the gelatin solution is 5%.

9. The self-dispersible pigment nano-paste according to claim 1, characterized in that: The pH value regulator is prepared from 2-aminopropanol, triethanolamine, sodium carbonate and sodium hexametaphosphate, and the mass ratio of the 2-aminopropanol, triethanolamine, sodium carbonate and sodium hexametaphosphate is 3:1:5:

2.

10. A method for preparing the self-dispersible pigment nano-color paste according to claims 1-9, characterized in that: At least the following steps are included: (1) Weigh the carbon black and add it into the ball mill. Adjust the speed of the ball mill to 600r / s and grind D95 ​​< 0.2μm; (2) The ground carbon black, surfactant, dispersant, ethylene glycol, stabilizer, and deionized water are weighed and placed in a mixing container to obtain a mixed solution; (3) The mixed solution is heated to 65°C, the pH adjuster is weighed and added to the mixed solution, the ball mill is started, the speed of the ball mill is adjusted to 600 r / s, and the components are ground and mixed uniformly by the ball mill to obtain a uniform mixture.

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