Preparation method of water-based environment-friendly pigment ink-jet printing ink

Abstract

The invention belongs to the technical field of ink-jet printing, and provides a preparation method of water-based environment-friendly pigment ink-jet printing ink, which comprises the following components: 70-85% of deionized water, 2-10% of pigment solute, 1-3% of cosolvent, 0.5-1% of surfactant, 0.2-1% of wetting agent, 2-5% of film-forming agent, 1-3% of coalescing agent and 0.5-2% of bacteriostatic agent. By increasing the use amount of the high-ionic-strength sodium polyacrylate resin in the ink, the adsorption effect of pigment particles on the surface of a medium is improved, the transverse and longitudinal diffusion effects of the pigment particles on the surface of the medium along with an ink solvent are reduced, and the purpose of improving the printing precision and color saturation of the ink-jet ink is achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of inkjet printing technology, in particular to a preparation method of water-based environment-friendly pigment inkjet printing ink. BACKGROUND

[0002] With the increasing awareness of environmental protection, traditional solvent-based printing ink is gradually restricted due to the pollution of volatile organic compounds and harm to the environment. In order to solve this problem, water-based environment-friendly printing ink has become a development trend in the market. Water-based ink uses water as the main solvent, has low toxicity, low volatility and good environmental friendliness, and meets the green environmental protection concept, so it is widely used in printing, spraying and packaging fields.

[0003] However, there are still some challenges in the use of traditional water-based ink, such as poor inkjet printing precision, low color saturation and other shortcomings. In the printing process of traditional water-based ink, pigment particles are prone to horizontal diffusion (causing halo) and vertical penetration (causing image blur) on the medium surface with water, especially on non-absorbing media (such as plastic film, coated paper). This is mainly due to the lack of effective control means for pigment particles in the existing ink system, resulting in a printing resolution generally lower than 1200 dpi, low color saturation, and unable to meet the requirements of high-end printing (such as advertising spraying, photography output) for details and color reproduction.

[0004] And the film-forming agent of conventional water-based ink mostly relies on a single resin, and the ink film is prone to have low hardness, poor flexibility, insufficient wear resistance and other problems after drying. For example, in packaging printing, the ink film is prone to scratches or peeling due to folding and rubbing; in the field of textile printing, the adhesion between the ink film and the fabric is insufficient, and the ink film is prone to fading or peeling after multiple washes, limiting the application of water-based ink in durable scenarios.

[0005] In addition, some existing technologies add high-toxicity organic solvents such as ethylene glycol butyl ether or cross-linking agents containing formaldehyde to improve the performance of the ink, which, although to some extent, improves the flowability or film-forming property of the ink, but violates the environmental protection intention of water-based ink, making it difficult to pass the food contact material safety certification and be used in fields with extremely high safety requirements such as food packaging and children's products. SUMMARY

[0006] In order to solve the above technical problems, the present application provides a preparation method of water-based environment-friendly pigment inkjet printing ink to solve the problems of poor printing precision and low color saturation of traditional printing ink.

[0007] According to a first aspect of the present disclosure, an aqueous environment-friendly pigment inkjet printing ink is provided, comprising the following components: 70-85% deionized water, 2-10% pigment solute, 1-3% cosolvent, 0.5-1% surfactant, 0.2-1% wetting agent, 2-5% film former, 1-3% film forming aid, and 0.5-2% bacteriostatic agent.

[0008] Preferably, the film former is a non-ionic resin and an aqueous polyacrylic acid sodium salt resin, an aqueous polyurethane resin, and an aqueous chlorovinyl resin.

[0009] Preferably, the cosolvent includes ethylene glycol, propylene glycol, glycerol, polyvinyl alcohol, and sodium pyrophosphate.

[0010] Preferably, the surfactant includes polyoxyethylene ether, ethoxylated fatty alcohol, and dimethyl diallyl ammonium chloride.

[0011] Preferably, the wetting agent includes acetylenic diol, 1-2 hexanediol, urea, and polyethylene glycol.

[0012] Preferably, the film forming aid includes a crosslinking agent, a co-crosslinking agent, a toughening agent, and a plasticizing agent.

[0013] Preferably, the bacteriostatic agent includes a silver-based bacteriostatic agent, a quaternary ammonium salt bacteriostatic agent, a copper-based bacteriostatic agent, and an organic acid bacteriostatic agent.

[0014] According to a second aspect of the present disclosure, a preparation method of an aqueous environment-friendly pigment inkjet printing ink is also provided, which is applied to the first aspect and comprises the following steps:

[0015] S1, pour deionized water into a reaction container, start low-speed stirring at 100-200 rpm, add pigment solute and surfactant in sequence, stir for 20-30 minutes to form a preliminary dispersion liquid;

[0016] S2, transfer the preliminary dispersion liquid to a sand mill, add an appropriate amount of glass beads or zirconia beads, and grind at a high speed of 1500-2000 rpm for 2-4 hours until the pigment particle size reaches the target range to obtain a sand-milled pigment dispersion liquid;

[0017] S3, return the sand-milled pigment dispersion liquid to the reaction container, maintain medium-speed stirring at 300-500 rpm, add cosolvent, wetting agent, film former, and film forming aid in sequence, wherein the film forming aid is added after the film former is completely dissolved after stirring for 20 minutes, stir for 5-10 minutes, and adjust the pH of the ink to 7.5-9.0 using ammonia water;

[0018] S4, turn off the stirrer, let the ink stand at room temperature for 12-24 hours to cure, so that the components are fully compatible, then filter the ink with a 0.2-0.45 um filter membrane to remove undispersed particles or impurities, and prepare the finished product.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] The present application improves the adsorption effect of pigment particles on the medium surface by increasing the amount of high ionic strength sodium polyacrylate resin in the ink, reduces the transverse and longitudinal diffusion effect of pigment particles following the solvent of the ink on the medium surface, and achieves the purpose of improving the printing precision and color saturation of the inkjet ink. Not only can the mechanical properties of the water-based printing ink be improved, but also the image clarity and color saturation of the printed product can be improved, and the overall ink components also maintain good environmental properties, effectively improving the applicability of the water-based ink. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The present application provides a water-based environmental protection pigment inkjet printing ink preparation method flow chart. DETAILED DESCRIPTION

[0022] The embodiments of the present application will be further described in detail below in conjunction with the drawings and examples. The following examples are used to illustrate the present application, but cannot be used to limit the scope of the present application.

[0023] Example 1: The present application provides a water-based environmental protection pigment inkjet printing ink, which comprises the following components: 70%-85% deionized water, 2%-10% pigment solute, 1%-3% cosolvent, 0.5%-1% surfactant, 0.2%-1% wetting agent, 2%-5% film former, 1%-3% film forming aid and 0.5%-2% bacteriostatic agent.

[0024] In the above components, the amount of sodium polyacrylate resin in the film former is 30%-70% of the total amount of the film former, according to the ionic strength of the sodium polyacrylate aqueous solution. Not only can the mechanical properties of the water-based printing ink be improved, but also the image clarity and color saturation of the printed product can be improved, and the overall ink components also maintain good environmental properties, effectively improving the applicability of the water-based ink.

[0025] The film former is a non-ionic resin and a water-based sodium polyacrylate resin, a water-based polyurethane resin and a water-based chlorovinyl resin.

[0026] The cosolvent includes ethylene glycol, propylene glycol, glycerol, polyvinyl alcohol and sodium pyrophosphate.

[0027] The surfactant includes polyoxyethylene ether, ethoxylated fatty alcohol, dimethyl diallyl ammonium chloride.

[0028] Wetting agents include acetylenic glycols, 1-2 hexanediol, urea, and polyethylene glycol.

[0029] Film-forming aids include crosslinking agents, co-crosslinking agents, toughening agents and plasticizers.

[0030] Antibacterial agents include silver-based antibacterial agents, quaternary ammonium salt antibacterial agents, copper-based antibacterial agents and organic acid antibacterial agents.

[0031] From the above, it can be seen that by increasing the polarity of the surface of the pigment particles in the water-based pigment ink, the lateral and longitudinal diffusion of the pigment particles on the medium surface can be reduced, which can effectively improve the printing accuracy and color saturation of inkjet printing.

[0032] Example 2: Figure 1 As shown, the present invention also provides a method for preparing a water-based environmentally friendly pigment inkjet printing ink, which is applied in Example 1 and includes the following steps:

[0033] S1. Pour deionized water into the reaction vessel, start low-speed stirring at 100-200 rpm, add pigment solute and surfactant in sequence, and stir for 20-30 minutes to form a preliminary dispersion; the surfactant is adsorbed on the surface of the pigment particles, further inhibiting particle aggregation through charge repulsion or steric hindrance effect, thereby improving storage stability.

[0034] S2. Transfer the preliminary dispersion to a sand mill, add an appropriate amount of glass beads or zirconia beads, and grind at a high speed of 1500-2000 rpm for 2-4 hours until the pigment particle size reaches the target range to obtain a sand-milled pigment dispersion; through the sand milling process, the pigment particles are fully broken up and evenly dispersed, avoiding ink precipitation or print head clogging caused by agglomeration.

[0035] S3. Return the sand-milled pigment dispersion to the reaction vessel, maintain stirring at a medium speed of 300-500 rpm, and add a cosolvent, a wetting agent, a film-forming agent, and a film-forming aid in sequence. After the film-forming agent is stirred for 20 minutes until it is completely dissolved, the film-forming aid is added and stirred for 5-10 minutes. Ammonia water is used to adjust the pH of the ink to 7.5-9.0. The wetting agent reduces the surface tension of the ink, promotes the rapid spreading of ink droplets on the substrate, reduces edge diffusion, and improves the edge clarity of the image. The film-forming agent and the film-forming aid work synergistically to allow the ink to dry quickly after printing to form a film, reducing the risk of smearing.

[0036] S4. Turn off the agitator and let the ink stand and mature at room temperature for 12 to 24 hours to make the components fully compatible. Then filter the ink through a 0.2 to 0.45 μm filter membrane to remove undispersed particles or impurities to obtain a finished product.

[0037] From the above, it can be seen that the overall preparation process does not require high temperature, high pressure or organic solvent extraction, has low energy consumption and no waste gas emissions, and meets the requirements of clean production.

[0038] It is to be understood that the development process can result in the formation of non- functional products such as intermediate products, which need not fulfill all of the objectives of the detailed embodiments of the present application. Similarly, it is to be understood that the

[0039] It should be noted that the above-mentioned embodiments illustrate rather than limit the application, since the technical solutions of the application can be modified or equivalent substitutes can be used without departing from the scope of the application.

Claims

1. A water-based environmentally friendly pigment inkjet printing ink, characterized in that: The invention comprises the following components: 70% to 85% of deionized water, 2% to 10% of pigment solute, 1% to 3% of cosolvent, 0.5% to 1% of surfactant, 0.2% to 1% of wetting agent, 2% to 5% of film-forming agent, 1% to 3% of film-forming auxiliary agent and 0.5% to 2% of antibacterial agent.

2. The water-based environmentally friendly pigment inkjet printing ink according to claim 1, characterized in that: The film-forming agents are nonionic resin, water-based sodium polyacrylate resin, water-based polyurethane resin and water-based chloroacetic acid resin.

3. The water-based environmentally friendly pigment inkjet printing ink according to claim 1, characterized in that: The cosolvents include ethylene glycol, propylene glycol, glycerol, polyvinyl alcohol and sodium pyrophosphate.

4. The water-based environmentally friendly pigment inkjet printing ink according to claim 1, characterized in that: The surfactant includes polyoxyethylene ether, ethoxylated fatty alcohol, and dimethyl diallyl ammonium chloride.

5. The water-based environmentally friendly pigment inkjet printing ink according to claim 1, characterized in that: The wetting agents include acetylenic glycol, 1-2 hexanediol, urea and polyethylene glycol.

6. The water-based environmentally friendly pigment inkjet printing ink according to claim 1, characterized in that: The film-forming aids include a cross-linking agent, a co-cross-linking agent, a toughening agent and a plasticizer.

7. The water-based environmentally friendly pigment inkjet printing ink according to claim 1, characterized in that: The antibacterial agent includes a silver-based antibacterial agent, a quaternary ammonium salt antibacterial agent, a copper-based antibacterial agent and an organic acid antibacterial agent.

8. A method for preparing a water-based environmentally friendly pigment inkjet printing ink, which is applied to the water-based environmentally friendly pigment inkjet printing ink according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Pour deionized water into the reaction vessel, start low-speed stirring at 100-200 rpm, add pigment solute and surfactant in sequence, and stir for 20-30 minutes to form a preliminary dispersion; S2. Transfer the preliminary dispersion to a sand mill, add an appropriate amount of glass beads or zirconia beads, and grind at a high speed of 1500-2000 rpm for 2-4 hours until the pigment particle size reaches the target range to obtain a sand-milled pigment dispersion; S3. Return the sand-milled pigment dispersion to the reaction vessel, maintain stirring at a medium speed of 300-500 rpm, and add a cosolvent, a wetting agent, a film-forming agent, and a film-forming aid in sequence. After the film-forming agent is stirred for 20 minutes until it is completely dissolved, the film-forming aid is added and stirred for 5-10 minutes. Ammonia water is then used to adjust the ink pH to 7.5-9.

0. S4. Turn off the agitator and let the ink stand and mature at room temperature for 12 to 24 hours to make the components fully compatible. Then filter the ink through a 0.2 to 0.45 μm filter membrane to remove undispersed particles or impurities to obtain a finished product.

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