Water-based high-covering quick-drying white ink and preparation method thereof

Abstract

The invention belongs to the technical field of digital ink-jet printing, and particularly relates to water-based high-covering quick-drying white ink and a preparation method thereof, expensive nano-scale titanium dioxide is replaced by a mode of compounding organic and inorganic light diffusion powder, so that the production cost is reduced; wherein the composite high-coverage white powder comprises modified nano calcium carbonate, organic silicon light diffusion microspheres and polymethyl methacrylate (PMMA) light diffusion microspheres, the modified nano calcium carbonate and the light diffusion powder can play a good extinction effect, the haze of the ink is well improved, meanwhile, the light transmittance of the ink is greatly reduced, the appearance of a product is more uniform, and the product quality is improved. And the overall performance is improved. Nano calcium carbonate is modified, and the crystal form is controlled after modification, so that the affinity of the nano calcium carbonate and organic microspheres is increased, the dispersity and interface contact strength of the nano calcium carbonate in an aqueous medium are improved, a uniform dispersion system is formed, the uniformity and stability of the white ink are improved, and the product performance of the white ink is further improved.

Description

Technical Field

[0001] The invention relates to the technical field of digital inkjet printing, in particular to a water-based high-hiding quick-drying white ink and a preparation method thereof. Background Art

[0002] Digital inkjet printing technology is a new textile printing technology that uses special dye ink or paint ink to print directly on textiles through an inkjet printer. Digital inkjet printing technology has high printing precision, does not require plate making, can realize personalized e-commerce consumption through the Internet, and does not waste dyes and auxiliaries.

[0003] Titanium dioxide is a commonly used white pigment. It can not only provide good whiteness by scattering light, but also has excellent hiding power. It is a commonly used colorant in industries such as coatings, papermaking, chemical fibers and natural latex. However, titanium dioxide is currently expensive, has high operating costs, and is prone to secondary pollution during the production process. Composite titanium dioxide, as a substitute for titanium dioxide, refers to an inorganic powder material that has the performance of titanium dioxide and is lower in cost than titanium dioxide, and can partially or completely replace titanium dioxide. However, most of the inorganic powder materials that are replaced today still contain a certain amount of titanium dioxide, such as Chinese patents CN101100561A, CN1724595A, etc. In terms of performance, there is currently no composite titanium dioxide that can replace the role of pure titanium dioxide in the market, such as reduced hiding power, insufficient weather resistance, and unsatisfactory color reduction performance. Therefore, the current titanium dioxide technology is to a certain extent a replacement of titanium dioxide at the expense of some of the performance that titanium dioxide should have, and it cannot completely replace titanium dioxide. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a water-based high-hiding quick-drying white ink and a preparation method thereof. Specifically, the present invention provides a white ink suitable for hot stamping and spray printing in daily use, which can quickly realize the construction of a white background on a nylon substrate or a nylon coating and has high hiding power.

[0005] To achieve the above purpose, the specific technical solutions of the present invention are as follows: The invention provides a water-based high-hiding quick-drying white ink, comprising the following components in mass fraction: 15% to 40% of white ink paste, 20% to 40% of thermoplastic acrylic resin, 5% to 10% of wetting agent, 5% to 10% of dispersant, 5% to 10% of functional resin, 0.2% to 1% of pH regulator, 0.5% to 1% of antibacterial agent, 0.2% to 0.5% of defoaming agent, and the balance of deionized water.

[0006] Furthermore, the wetting agent is one or more of propylene glycol, glycerol, diethylene glycol, triethylene glycol, and ethylene glycol.

[0007] Furthermore, the dispersant is one or more of TEGO-715W, SN 5040, and BYK 110.

[0008] Furthermore, the functional resin is one or more of sodium carboxymethyl cellulose, hydroxypropyl methyl cellulose, and polyvinyl alcohol.

[0009] Furthermore, the pH adjuster is one or more of triethanolamine and dimethylethanolamine.

[0010] Furthermore, the antibacterial agent is one or more of VOK-LB401 and AM-0209.

[0011] Furthermore, the defoaming agent is one or more of DU-159 and AC-2010.

[0012] Furthermore, the white ink paste includes the following components in mass fractions: 20% to 40% of composite high hiding white powder, 2% to 5% of aqueous silica sol, 10% to 20% of composite dispersant, 1% to 10% of wetting agent, and balance of deionized water.

[0013] Furthermore, the preparation method of the white ink paste is as follows: (1) Add the composite high-covering white powder and the composite dispersant into the reactor in sequence and stir for 10 to 20 minutes until the powder is evenly dispersed to obtain material 1; (2) Add aqueous silica sol, wetting agent and deionized water to material 1 and stir for 30 to 60 minutes to obtain white ink paste.

[0014] Furthermore, the composite high-hiding white powder is a mixed powder of nano-calcium carbonate, silicone light-diffusing microspheres, and polymethyl methacrylate (PMMA) light-diffusing microspheres, with a mass ratio of 3:1:1. The particle size of the nano-calcium carbonate is less than 200 nm, and the particle sizes of the silicone light-diffusing microspheres and the polymethyl methacrylate (PMMA) light-diffusing microspheres are less than 150 nm.

[0015] Furthermore, the particle size of the aqueous silica sol is 10 to 50 nm.

[0016] Furthermore, the composite dispersant is a combination of a wetting dispersant KMT-3003 and a synergistic dispersant AG-330, and the mass ratio of the two is 5:1.

[0017] Furthermore, the wetting agent is one or more of propylene glycol, glycerol, diethylene glycol, triethylene glycol, and ethylene glycol.

[0018] Different from traditional white ink that uses nano-scale titanium dioxide as white pigment, the quick-drying white ink of the present invention adopts a compounding method of organic and inorganic light-diffusing powders. Calcium carbonate as inorganic particles has high hardness and stability, and can improve the wear resistance, weather resistance and moisture absorption resistance of white ink. Silicone light-diffusing microspheres and PMMA light-diffusing microspheres as organic particles have good flexibility and optical properties, and can enhance the brushability, adsorption and fading resistance of white ink. This compounding method can completely replace expensive nano-scale titanium dioxide and reduce production costs. Moreover, three kinds of light-diffusing powders with different particle sizes are used, among which the particle size of calcium carbonate is less than 200nm, and the particle sizes of silicone light-diffusing microspheres and PMMA light-diffusing microspheres are less than 150nm. The combination of different particle sizes enables the white ink to form a multi-level particle distribution in the microstructure. The smaller-sized silicone light-diffusing microspheres and PMMA light-diffusing microspheres can fill the gaps between the larger-sized calcium carbonate particles to form a compact stacking structure, thereby improving the density and hiding power of the white ink. At the same time, particles of different particle sizes have different scattering effects on light, and can effectively scatter light at different angles and wavelengths, further improving the hiding power of the white ink. When quick-drying white ink is sprayed on the surface of the fabric, the unevenness of the particles at the microscopic level scatters the light, which can achieve a good matting effect and increase the haze of the ink. At the same time, it also greatly reduces its light transmittance, making the product appearance more uniform, improving its overall appearance texture and quality. The hiding power, brushability, adsorption, moisture absorption resistance, and fading resistance of the white ink are significantly improved.

[0019] The composite dispersant composed of wetting dispersant KMT-3003 and synergistic dispersant AG-330 in a mass ratio of 5:1 has a good dispersing effect on the high-hiding white powder composite of nano-calcium carbonate, nano-silicon microspheres and polymethyl methacrylate (PMMA) microspheres, and can change the dispersion and wetting properties of the powder, making it have good dispersibility and weather resistance.

[0020] Aqueous silica sol has a large specific surface area and adsorption capacity. Under certain conditions, it can make the composite white powder have a certain adsorption effect to make the system more stable, and act as a "bridge" to achieve cross-linking construction between the substrate and the ink body during printing. Functional resin can adjust the viscosity of the ink, effectively prevent the precipitation of particles in the ink, maintain the uniformity and stability of the ink, prevent the ink from settling and stratification, and has good emulsification, dispersion, suspension and bonding effects, making it easier to level during printing; at the same time, it can also enhance the adhesion between the coating and the substrate, making the printed pattern more uniform and smooth, and improving the printing effect and protection performance.

[0021] However, nano-calcium carbonate is an inorganic powder material, which not only has poor compatibility with organic microspheres, but also easily agglomerates in aqueous media. It must undergo surface modification to increase its affinity with organic microspheres and improve its dispersibility and interfacial contact strength in aqueous media to make it evenly dispersed.

[0022] Furthermore, the preparation method of modified nano calcium carbonate comprises the following steps: S11: The refined Ca(OH)2 slurry is aged for 12 to 24 hours, and the slag is removed by a vibrating screen and a cyclone separator at level 6. The collected sieve powder is mixed evenly with deionized water to obtain a Ca(OH)2 slurry; S12: The Ca(OH)2 slurry is heated while being stirred, and a modifier of 5% to 10% by mass of Ca(OH)2 is added after the temperature reaches 80-85°C. After the addition is completed, the pH value is adjusted to 8.0-8.5. After constant temperature stirring at 80-90°C for 60-90min, the mixture is cooled to 30-40°C, and CO2 gas with a volume concentration of 20% to 40% is introduced for bubbling carbonization reaction until the slurry pH value is 7.0-7.5. The slurry is heated to 50-60°C, and a modifier of 5% to 10% by mass of Ca(OH)2 is added. After the addition is completed, the pH value is adjusted to 8.0-8.5. After constant temperature stirring at 50-60°C for 90-120min, the mixture is cooled to 30-40°C, and CO2 gas with a volume concentration of 20% to 40% is introduced for bubbling carbonization reaction until the slurry pH value is 6.5-7.0, thereby obtaining a cooked slurry; S13: Stir and heat the cooked slurry, and when the temperature reaches 30-40°C, add 0.5%-1.5% of the mass of Ca(OH)2 crystal control agent A liquid, stir and mix evenly, then add 0.5%-1.5% of the mass of Ca(OH)2 crystal control agent B liquid, stir and mix evenly, cool to room temperature, filter and separate, wash, dry and grind in sequence to obtain modified nano calcium carbonate with a particle size of less than 200nm.

[0023] Furthermore, the mass ratio of the sieved Ca(OH)2 powder and deionized water in step S11 is Ca(OH)2 powder:deionized water=1:10-15.

[0024] Furthermore, the modifier in step S12 is a mixed solution of KH550 (γ-aminopropyltriethoxysilane) and sodium dodecyl sulfate, wherein the mass percentage of KH550 is 3% to 4%, and the mass percentage of sodium dodecyl sulfate is 1% to 2%.

[0025] Furthermore, the crystal form control agent of step S13 includes liquid A and liquid B, liquid A is an aqueous solution of 10-20 g / L EDTA (ethylenediaminetetraacetic acid), liquid B is a polyvinyl alcohol composite liquid, and the preparation method of liquid B is: prepare a sodium citrate solution with a mass percentage of 2% to 5%, add polyvinyl alcohol to the sodium citrate solution, stir well, and then heat the solution to 45-50° C., and then add tocopherol to the solution under stirring, stir for 30-60 minutes after the addition is completed, and then add titanium dioxide powder and magnesium chloride powder to the solution under stirring, continue stirring for 10-15 minutes after the addition is completed, filter to remove the insoluble phase, and obtain liquid B.

[0026] Preferably, the mass ratio of polyvinyl alcohol added to the sodium citrate solution is polyvinyl alcohol: sodium citrate solution = 3-4:100; the mass ratio of the added mass of tocopherol, titanium dioxide powder and magnesium chloride powder to the polyvinyl alcohol is tocopherol: titanium dioxide powder: magnesium chloride powder: polyvinyl alcohol = 1-2g: 2-3g: 0.6-0.9g: 1-2g.

[0027] In the present invention, nano-calcium carbonate is first modified and then crystal form control is performed. If crystal form control is performed first and then modified, the modification process may have an unpredictable effect on the crystal form, increasing the uncertainty of crystal form control, and first modification and then crystal form control can reduce this uncertainty. The modifier is a mixed solution of KH550 and sodium dodecyl sulfate. The ethoxy group in the molecular structure of KH550 can hydrolyze with the hydroxyl group on the surface of calcium carbonate to form a silanol bond, and then the silanol bonds or the hydroxyl groups on the surface of calcium carbonate are further condensed to form a stable chemical bond on the surface of nano-calcium carbonate. This chemical bonding makes the surface of nano-calcium carbonate covered with a layer of organic silane layer. The introduction of the organic silane layer makes the surface of nano-calcium carbonate have certain organic characteristics, which is more similar to the surface properties of organic microspheres, so that the compatibility between nano-calcium carbonate and organic microspheres can be improved, and the interfacial tension between the two can be reduced. Good compatibility helps nano-calcium carbonate and organic microspheres to better combine to form a uniform dispersion system, thereby improving the uniformity and stability of white ink. Moreover, the organosilane layer on the surface of the modified nano-calcium carbonate can also interact with the molecules in the aqueous medium. The long-chain structure of the organosilane layer can prevent the particles from approaching and agglomerating each other, maintain the dispersed state of the particles, form a steric hindrance effect, and further improve the stability and uniformity of the entire white ink system. As an anionic surfactant, the hydrophilic end of sodium dodecyl sulfate is adsorbed on the surface of nano-calcium carbonate, and the hydrophobic end faces the outside to interact with the aqueous medium, significantly reducing the surface energy of the particles and having hydrophilicity, which can not only reduce the agglomeration between particles, but also make nano-calcium carbonate more easily dispersed in the aqueous medium. Therefore, KH550 and sodium dodecyl sulfate in the modifier improve the compatibility and dispersibility of nano-calcium carbonate through surface chemical modification, and improve the interface contact strength, significantly improve the performance of nano-calcium carbonate, and form a more stable dispersion system on the surface of nano-calcium carbonate, so that it has a stronger ability to bind with organic microspheres and can prevent the agglomeration and precipitation of particles.

[0028] Crystal form control agent A liquid is an aqueous solution of EDTA, which can form a complex with calcium ions to control the crystallization process of calcium carbonate. Crystal form control agent B liquid is a polyvinyl alcohol composite liquid, which can be adsorbed on the surface of calcium carbonate crystals to affect the growth habits of the crystals and thus control the crystal form; sodium citrate can form a complex with calcium ions to further regulate the crystallization process; tocopherol, titanium dioxide powder and magnesium chloride powder may also interact with calcium carbonate crystals to affect the crystal form and performance.

[0029] The present invention provides a method for preparing a water-based high-hiding quick-drying white ink, the method comprising the following steps: S1: Add white ink paste, thermoplastic acrylic resin and functional resin into the reactor in sequence, stir for 20 to 30 minutes until the paste is evenly dispersed, then add wetting agent and dispersant, and continue stirring for 20 to 30 minutes to obtain a crude white ink; S2: Add the defoamer into the remaining deionized water and stir for 10 to 15 minutes, then pour into the crude white ink mixed solution and stir for 20 to 30 minutes to obtain a mixed solution 1; S3: Add pH regulator and antibacterial agent to mixed solution 1, stir for 30-60 minutes to obtain mixed solution 2, filter mixed solution 2 through a 400-mesh fine mesh twice to obtain high-coverage quick-drying white ink.

[0030] Furthermore, the suitable range of pH adjustment in step S3 is 6.0 to 8.0.

[0031] The beneficial effects of the present invention are: The present invention provides a water-based high-hiding quick-drying white ink and a preparation method thereof, wherein the composite high-hiding white powder is a mixed powder of nano-calcium carbonate, silicone light-diffusing microspheres, and polymethyl methacrylate (PMMA) light-diffusing microspheres in a mass ratio of 3:1:1, and the modified nano-calcium carbonate and light-diffusing powder have a scattering effect on light, which can play a good extinction effect, greatly improve the haze of the ink, and also greatly reduce its light transmittance, so that the product appearance is more uniform and the overall performance is improved. This method of compounding organic and inorganic light-diffusing powders can completely replace expensive nano-scale titanium dioxide and reduce production costs. In the present invention, the affinity of nano-calcium carbonate and organic microspheres is increased by modifying the nano-calcium carbonate, first modifying and then controlling the crystal form, and the dispersibility and interface contact strength of the nano-calcium carbonate in the aqueous medium are improved to form a uniform dispersion system, improve the uniformity and stability of the white ink, and thus improve the product performance of the white ink. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with the examples, but the present invention is not limited thereby. The experimental methods in the following examples are conventional methods unless otherwise specified.

[0033] Example 1 A water-based high-hiding quick-drying white ink comprises the following components by mass fraction: 15% to 40% white ink paste, 20% thermoplastic acrylic resin, 5% wetting agent, 5% dispersant, 5% functional resin, 0.2% pH regulator, 0.5% antibacterial agent, 0.2% defoamer, and the balance deionized water. The wetting agent is propylene glycol, the dispersant is TEGO-715W, the functional resin is sodium carboxymethyl cellulose, the pH regulator is triethanolamine, the antibacterial agent is VOK-LB401, and the defoamer is DU-159.

[0034] The white ink paste includes the following components by mass fraction: 20% composite high hiding white powder, 2% aqueous silica sol, 10% composite dispersant, 1% wetting agent, and the balance of deionized water. The composite high hiding white powder is a mixed powder of modified nano calcium carbonate, organic silicon light diffusion microspheres, and polymethyl methacrylate (PMMA) light diffusion microspheres, and the wetting agent is propylene glycol.

[0035] The preparation method of modified nano calcium carbonate comprises the following steps: S11: The refined Ca(OH)2 slurry is aged for 12 hours, and the slag is removed by a vibrating screen and a cyclone separator at level 6. The collected sieve powder is mixed evenly with deionized water, and the mass ratio of Ca(OH)2 powder to deionized water is Ca(OH)2 powder: deionized water = 1:10, to obtain a Ca(OH)2 slurry; S12: The Ca(OH)2 slurry is heated while being stirred. After the temperature reaches 80°C, a modifier of 5% by mass of Ca(OH)2 is added. The modifier is a mixed solution of 3% by mass of KH550 and 1% by mass of sodium dodecyl sulfate. After the addition is completed, the pH value is adjusted to 8.0. After constant temperature stirring at 80°C for 60 minutes, the mixture is cooled to 30°C, and CO2 gas with a volume concentration of 20% is introduced for bubbling carbonization reaction until the slurry pH is 7.0. The slurry is heated to 50°C, and a modifier of 5% by mass of Ca(OH)2 is added. After the addition is completed, the pH value is adjusted to 8.0. After constant temperature stirring at 50°C for 90 minutes, the mixture is cooled to 30°C, and CO2 gas with a volume concentration of 20% is introduced for bubbling carbonization reaction until the slurry pH reaches 6.5, thereby obtaining a cooked slurry. S13: Stir and heat the cooked slurry. When the temperature reaches 30°C, add 0.5% of the mass of Ca(OH)2 crystal control agent A liquid, and the A liquid is 10g / L The EDTA aqueous solution is stirred and mixed evenly, and then a crystal form control agent B liquid of 0.5% of the mass of Ca(OH)2 is added, and the B liquid is a polyvinyl alcohol composite liquid. The preparation method is as follows: a sodium citrate solution with a mass percentage of 2% is prepared, polyvinyl alcohol is added to the sodium citrate solution, polyvinyl alcohol: sodium citrate solution = 3:100, and the solution is fully stirred and evenly heated to 45°C, and then tocopherol is added to the solution under stirring, and the solution is stirred for 30 minutes after the addition is completed, and then titanium dioxide powder and magnesium chloride powder are added to the solution under stirring, tocopherol: titanium dioxide powder: magnesium chloride powder: polyvinyl alcohol = 1g:2g:0.6g:1g, and the addition is continued to be stirred for 10 minutes, and the insoluble phase is removed by filtering to obtain the B liquid; after adding the B liquid and stirring and mixing evenly, the mixture is cooled to room temperature, and filtered, separated, washed, dried, and ground in sequence to obtain a modified nano calcium carbonate with a particle size less than 200nm.

[0036] The present invention provides a method for preparing a water-based high-hiding quick-drying white ink, the method comprising the following steps: S1: Add the composite high-covering white powder and the composite dispersant into the reactor in sequence, and stir for 10 minutes until the powder is evenly dispersed to obtain material 1; S2: Add aqueous silica sol, wetting agent and deionized water to material 1, and stir for 30 minutes to obtain white ink paste; S3: Add white ink paste, thermoplastic acrylic resin, and functional resin into the reactor in sequence, stir for 20 minutes until the paste is evenly dispersed, then add a wetting agent and a dispersant, and continue stirring for 20 minutes to obtain a crude white ink; S4: Add the defoamer into the remaining deionized water and stir for 10 minutes, then pour into the crude white ink mixed solution and stir for 20 minutes to obtain a mixed solution 1; S5: Add pH adjuster and antibacterial agent to mixed solution 1, adjust the pH to 6.0, stir for 30 minutes to obtain mixed solution 2, filter mixed solution 2 through a 400-mesh fine mesh twice to obtain high-coverage quick-drying white ink.

[0037] Example 2 A water-based high-hiding quick-drying white ink comprises the following components by mass fraction: 40% white ink paste, 40% thermoplastic acrylic resin, 10% wetting agent, 10% dispersant, 10% functional resin, 1% pH regulator, 1% antibacterial agent, 0.5% defoamer, and the balance deionized water. The wetting agent is propylene glycol, the dispersant is TEGO-715W, the functional resin is sodium carboxymethyl cellulose, the pH regulator is triethanolamine, the antibacterial agent is VOK-LB401, and the defoamer is DU-159.

[0038] The white ink paste includes the following components by mass fraction: 40% composite high hiding white powder, 5% aqueous silica sol, 20% composite dispersant, 10% wetting agent, and the balance of deionized water. The composite high hiding white powder is a mixed powder of modified nano calcium carbonate, organic silicon light diffusion microspheres, and polymethyl methacrylate (PMMA) light diffusion microspheres, and the wetting agent is propylene glycol.

[0039] The preparation method of modified nano calcium carbonate comprises the following steps: S11: The refined Ca(OH)2 slurry is aged for 24 hours, and the slag is removed by a vibrating screen and a cyclone separator at level 6. The collected sieve powder is mixed evenly with deionized water, and the mass ratio of Ca(OH)2 powder to deionized water is Ca(OH)2 powder: deionized water = 1:15, to obtain a Ca(OH)2 slurry; S12: The Ca(OH)2 slurry is heated while being stirred. After the temperature reaches 85°C, a modifier of 10% by mass of Ca(OH)2 is added. The modifier is a mixed solution of 4% by mass of KH550 and 2% by mass of sodium dodecyl sulfate. After the addition is completed, the pH value is adjusted to 8.5. After constant temperature stirring at 90°C for 90 minutes, the mixture is cooled to 40°C, and CO2 gas with a volume concentration of 40% is introduced for bubbling carbonization reaction until the slurry pH is 7.5. The slurry is heated to 60°C, and a modifier of 10% by mass of Ca(OH)2 is added. After the addition is completed, the pH value is adjusted to 8.5. After constant temperature stirring at 60°C for 120 minutes, the mixture is cooled to 30-40°C, and CO2 gas with a volume concentration of 40% is introduced for bubbling carbonization reaction until the slurry pH reaches 7.0, thereby obtaining a cooked slurry. S13: Stir and heat the cooked slurry until the temperature reaches 40°C, add 1.5% of the mass of Ca(OH)2 crystal control agent A solution, the A solution is 20g / L The EDTA aqueous solution is stirred and mixed evenly, and then a crystal form control agent B liquid of 1.5% of the mass of Ca(OH)2 is added, and the B liquid is a polyvinyl alcohol composite liquid. The preparation method is as follows: a sodium citrate solution with a mass percentage of 5% is prepared, polyvinyl alcohol is added to the sodium citrate solution, polyvinyl alcohol: sodium citrate solution = 4:100, and the solution is fully stirred and evenly mixed, and then the solution is heated to 50°C, and then tocopherol is added to the solution under stirring, and the solution is stirred for 60 minutes after the addition is completed, and then titanium dioxide powder and magnesium chloride powder are added to the solution under stirring, tocopherol: titanium dioxide powder: magnesium chloride powder: polyvinyl alcohol = 2g:3g:0.9g:2g, and the addition is continued to be stirred for 15 minutes, and the insoluble phase is removed by filtering to obtain the B liquid; after adding the B liquid and stirring and mixing evenly, the mixture is cooled to room temperature, and filtered, separated, washed, dried, and ground in sequence to obtain a modified nano calcium carbonate with a particle size less than 200nm.

[0040] The present invention provides a method for preparing a water-based high-hiding quick-drying white ink, the method comprising the following steps: S1: Add the composite high-covering white powder and the composite dispersant into the reactor in sequence and stir for 20 minutes until the powder is evenly dispersed to obtain material 1; S2: Add aqueous silica sol, wetting agent and deionized water to material 1, and stir for 60 minutes to obtain white ink paste; S3: Add white ink paste, thermoplastic acrylic resin, and functional resin into the reactor in sequence, stir for 30 minutes until the paste is evenly dispersed, then add a wetting agent and a dispersant, and continue stirring for 30 minutes to obtain a crude white ink; S4: Add the defoamer into the remaining deionized water and stir for 15 minutes, then pour into the crude white ink mixed solution and stir for 30 minutes to obtain a mixed solution 1; S5: Add pH adjuster and antibacterial agent to mixed solution 1, adjust the pH to 8.0, stir for 60 minutes to obtain mixed solution 2, filter mixed solution 2 through a 400-mesh fine mesh twice to obtain high-coverage quick-drying white ink.

[0041] Example 3 A water-based high-hiding quick-drying white ink comprises the following components by mass fraction: 15% to 40% white ink paste, 30% thermoplastic acrylic resin, 7.5% wetting agent, 7.5% dispersant, 7.5% functional resin, 0.6% pH regulator, 0.75% antibacterial agent, 0.35% defoamer, and the balance is deionized water. The wetting agent is propylene glycol, the dispersant is TEGO-715W, the functional resin is sodium carboxymethyl cellulose, the pH regulator is triethanolamine, the antibacterial agent is VOK-LB401, and the defoamer is DU-159.

[0042] The white ink paste includes the following components by mass fraction: 30% composite high hiding white powder, 3.5% aqueous silica sol, 15% composite dispersant, 5% wetting agent, and the balance of deionized water. The composite high hiding white powder is a mixed powder of modified nano calcium carbonate, organic silicon light diffusion microspheres, and polymethyl methacrylate (PMMA) light diffusion microspheres, and the wetting agent is propylene glycol.

[0043] The preparation method of modified nano calcium carbonate comprises the following steps: S11: The refined Ca(OH)2 slurry is aged for 18 hours, and then deslagging is performed through a vibrating screen and a cyclone separator for 6 stages. The collected sieve powder is mixed evenly with deionized water, and the mass ratio of Ca(OH)2 powder to deionized water is Ca(OH)2 powder: deionized water = 1:12.5, to obtain a Ca(OH)2 slurry; S12: The Ca(OH)2 slurry is heated while being stirred. After the temperature reaches 82.5°C, a modifier of 7.5% by mass of Ca(OH)2 is added. The modifier is a mixed solution of 3.5% by mass of KH550 and 1.5% by mass of sodium dodecyl sulfate. After the addition is completed, the pH value is adjusted to 8.25. After constant temperature stirring at 85°C for 75 minutes, the mixture is cooled to 35°C, and CO2 gas with a volume concentration of 30% is introduced for bubbling carbonization reaction until the slurry pH is 7.3. The slurry is heated to 55°C, and a modifier of 7.5% by mass of Ca(OH)2 is added. After the addition is completed, the pH value is adjusted to 8.3. After constant temperature stirring at 55°C for 105 minutes, the mixture is cooled to 35°C, and CO2 gas with a volume concentration of 30% is introduced for bubbling carbonization reaction until the slurry pH reaches 6.7, thereby obtaining a cooked slurry. S13: Stir and heat the cooked slurry until the temperature reaches 35°C, add 1.0% of the mass of Ca(OH)2 crystal form control agent A solution, the concentration of A solution is 15g / L The EDTA aqueous solution is stirred and mixed evenly, and then a crystal form control agent B liquid of 1.0% of the mass of Ca(OH)2 is added, and the B liquid is a polyvinyl alcohol composite liquid. The preparation method is as follows: a sodium citrate solution with a mass percentage of 3.5% is prepared, polyvinyl alcohol is added to the sodium citrate solution, polyvinyl alcohol: sodium citrate solution = 3.5:100, and the solution is fully stirred and evenly heated to 47.5°C, and then tocopherol is added to the solution under stirring, and the solution is stirred for 45 minutes after the addition is completed, and then titanium dioxide powder and magnesium chloride powder are added to the solution under stirring, tocopherol: titanium dioxide powder: magnesium chloride powder: polyvinyl alcohol = 1.5g:2.5g:0.75g:1.5g, and the addition is continued to stir for 12.5 minutes, and the insoluble phase is removed by filtering to obtain the B liquid; after adding the B liquid and stirring and mixing evenly, the solution is cooled to room temperature, and filtered, separated, washed, dried, and ground in sequence to obtain a modified nano calcium carbonate with a particle size less than 200nm.

[0044] The present invention provides a method for preparing a water-based high-hiding quick-drying white ink, the method comprising the following steps: S1: Add the composite high-covering white powder and the composite dispersant into the reactor in sequence, and stir for 10 to 20 minutes until the powder is evenly dispersed to obtain material 1; S2: Add aqueous silica sol, wetting agent and deionized water to material 1, and stir for 45 minutes to obtain white ink paste; S3: Add white ink paste, thermoplastic acrylic resin, and functional resin into the reactor in sequence, stir for 25 minutes until the paste is evenly dispersed, then add a wetting agent and a dispersant, and continue stirring for 25 minutes to obtain a crude white ink; S4: Add the defoamer into the remaining deionized water and stir for 12.5 minutes, then pour into the crude white ink mixed solution and stir for 25 minutes to obtain a mixed solution 1; S5: Add pH adjuster and antibacterial agent to mixed solution 1, adjust the pH to 7.0, stir for 45 minutes to obtain mixed solution 2, filter mixed solution 2 through a 400-mesh fine mesh twice to obtain high-coverage quick-drying white ink.

[0045] Comparative Example 1: This comparative example 1 is basically the same as Example 3, except that the composite high hiding white powder does not contain modified nano calcium carbonate.

[0046] Comparative Example 2: This comparative example 2 is basically the same as Example 3, except that the composite high hiding white powder does not contain silicone light diffusing microspheres.

[0047] Comparative Example 3: This comparative example 3 is substantially the same as Example 3, except that the composite high hiding white powder does not contain polymethyl methacrylate (PMMA) light diffusing microspheres.

[0048] Test experiment: The six samples of Examples 1-3 and Comparative Examples 1-3 were used as test samples for testing, and the test results are shown in Table 1.

[0049] 1. The rubbing fastness test is to test the rubbing fastness of white ink with reference to GB / T 3920-2008 "Textiles - Tests for Colour Fastness - Colour Fastness to Rubbing".

[0050] 2. The color fastness to washing test is to test the color fastness to washing of white ink with reference to GB / T3920-2008 "Textiles - Tests for Color Fastness - Color Fastness to Washing with Soap".

[0051] 3. The whiteness test is carried out according to the method specified in Appendix B of the chemical industry standard "HG / T4786-2014 Latex Color Paste".

[0052] 4. The yellowing value test is carried out on white ink in accordance with GB / T 19437-2004, "Printing Technology - Spectral Measurement and Chromaticity Calculation of Printed Images".

[0053] Table 1 Performance test results Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Dry rubbing fastness / grade 5 5 4 3 3-4 3-4 Wet rubbing fastness / grade 5 4 4 3 4 3 Ink drying time / s 32 39 41 72 69 66 Whiteness / ° 99.6 93.1 96.7 76.8 79.1 79.9 Yellowing value ∆b<0.15 pass pass pass Not passed Not passed Not passed The white ink in the embodiment performs well in the dry friction fastness and wet friction fastness tests, reaching the level of 4 or 5, which shows that the composite high hiding white powder can improve the adhesion and wear resistance of the white ink, and is not easy to fall off and wear during use. The white ink in the embodiment has a shorter drying time of 32-41s, which is significantly lower than the 66-72s of the comparative example, has good drying performance, can be quickly cured, and improves production efficiency; the whiteness of the white ink in the embodiment is relatively high, between 93.1-99.6°, which is significantly higher than the 76.8-79.9° of the comparative example. The yellowing value ∆b of the white ink in the embodiment is less than 0.15, which passes the yellowing value test, while the comparative example does not pass, indicating that the comparative example samples have good yellowing resistance and can maintain color stability during long-term use. Compared with the comparative example, the embodiment contains a composite high hiding white powder, and the performance in various aspects is better than the comparative example group. Comparative Example 1 lacks modified nano-calcium carbonate, Comparative Example 2 lacks silicone light-diffusing microspheres, and Comparative Example 1 lacks polymethyl methacrylate (PMMA) light-diffusing microspheres, resulting in the performance of the comparative examples being lower than that of the samples in the embodiment group, especially Comparative Example 1 having the lowest performance, indicating that modified nano-calcium carbonate can significantly enhance the performance of white ink.

[0054] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A water-based high-hiding quick-drying white ink, characterized in that: The invention comprises the following components in mass fraction: 15% to 40% white ink paste, 20% to 40% thermoplastic acrylic resin, 5% to 10% wetting agent, 5% to 10% dispersant, 5% to 10% functional resin, 0.2% to 1% pH adjuster, 0.5% to 1% antibacterial agent, 0.2% to 0.5% defoaming agent and the balance deionized water.

2. The water-based high-hiding quick-drying white ink according to claim 1, characterized in that: The wetting agent is one or more of propylene glycol, glycerol, diethylene glycol, triethylene glycol, and ethylene glycol; the dispersant is one or more of TEGO-715W, SN 5040, and BYK110; the functional resin is one or more of sodium carboxymethyl cellulose, hydroxypropyl methylcellulose, and polyvinyl alcohol; the pH regulator is one or more of triethanolamine and dimethylethanolamine; the antibacterial agent is one or more of VOK-LB401 and AM-0209; and the defoaming agent is one or more of DU-159 and AC-2010.

3. The water-based high-hiding quick-drying white ink according to claim 1, characterized in that: The white ink paste comprises the following components in mass fraction: 20% to 40% of composite high hiding white powder, 2% to 5% of aqueous silica sol, 10% to 20% of composite dispersant, 1% to 10% of wetting agent, and the balance of deionized water.

4. The water-based high-hiding quick-drying white ink according to claim 3, characterized in that: The preparation method of the white ink paste is as follows: (1) Add the composite high-covering white powder and the composite dispersant into the reactor in sequence and stir for 10 to 20 minutes until the powder is evenly dispersed to obtain material 1; (2) Add aqueous silica sol, wetting agent and deionized water to material 1 and stir for 30 to 60 minutes to obtain white ink paste.

5. The water-based high-hiding quick-drying white ink according to claim 4, characterized in that: The composite high hiding white powder is a mixed powder of modified nano calcium carbonate, silicone light diffusion microspheres, and polymethyl methacrylate light diffusion microspheres, the mass ratio of the three being 3:1:1, the particle size of the modified nano calcium carbonate being less than 200 nm, and the particle sizes of the silicone light diffusion microspheres and the polymethyl methacrylate light diffusion microspheres being less than 150 nm.

6. The water-based high-hiding quick-drying white ink according to claim 4, characterized in that: The particle size of the aqueous silica sol is 10 to 50 nm, the composite dispersant is a combination of a wetting dispersant KMT-3003 and a co-dispersant AG-330 in a mass ratio of 5:1, and the wetting agent is one or more of propylene glycol, glycerol, diethylene glycol, triethylene glycol, and ethylene glycol.

7. The water-based high-hiding quick-drying white ink according to claim 5, characterized in that: The preparation method of the modified nano calcium carbonate comprises the following steps: S11: The refined Ca(OH)2 slurry is aged for 12 to 24 hours, and the slag is removed by a vibrating screen and a cyclone separator at level 6. The collected sieve powder is mixed evenly with deionized water to obtain a Ca(OH)2 slurry; S12: The Ca(OH)2 slurry is heated while being stirred, and a modifier of 5% to 10% by mass of Ca(OH)2 is added after the temperature reaches 80-85°C. After the addition is completed, the pH value is adjusted to 8.0-8.

5. After constant temperature stirring at 80-90°C for 60-90min, the mixture is cooled to 30-40°C, and CO2 gas with a volume concentration of 20% to 40% is introduced for bubbling carbonization reaction until the slurry pH value is 7.0-7.

5. The slurry is heated to 50-60°C, and a modifier of 5% to 10% by mass of Ca(OH)2 is added. After the addition is completed, the pH value is adjusted to 8.0-8.

5. After constant temperature stirring at 50-60°C for 90-120min, the mixture is cooled to 30-40°C, and CO2 gas with a volume concentration of 20% to 40% is introduced for bubbling carbonization reaction until the slurry pH value is 6.5-7.0, thereby obtaining a cooked slurry; S13: Stir and heat the cooked slurry, and when the temperature reaches 30-40°C, add 0.5%-1.5% of the mass of Ca(OH)2 crystal control agent A liquid, stir and mix evenly, then add 0.5%-1.5% of the mass of Ca(OH)2 crystal control agent B liquid, stir and mix evenly, cool to room temperature, filter and separate, wash, dry and grind in sequence to obtain modified nano calcium carbonate with a particle size of less than 200nm.

8. The water-based high-hiding quick-drying white ink according to claim 5, characterized in that: The mass ratio of the sieved Ca(OH)2 powder and deionized water in step S11 is Ca(OH)2 powder: deionized water = 1:10-15; the modifier in step S12 is a mixed solution of KH550 and sodium dodecyl sulfate, wherein the mass percentage of KH550 is 3%-4%, and the mass percentage of sodium dodecyl sulfate is 1%-2%; the crystal form control agent in step S13 includes liquid A and liquid B, and liquid A is 10-20 g / L The aqueous solution of EDTA, liquid B is a polyvinyl alcohol composite liquid, and the preparation method of liquid B is: prepare a sodium citrate solution with a mass percentage of 2% to 5%, add polyvinyl alcohol to the sodium citrate solution, stir it evenly, then heat the solution to 45 to 50° C., then add tocopherol to the solution under stirring, stir for 30 to 60 minutes after the addition is completed, then add titanium dioxide powder and magnesium chloride powder to the solution under stirring, continue to stir for 10 to 15 minutes after the addition is completed, filter to remove the insoluble phase, and obtain liquid B.

9. The water-based high-hiding quick-drying white ink according to claim 8, characterized in that: The mass ratio of polyvinyl alcohol added to the sodium citrate solution is polyvinyl alcohol: sodium citrate solution = 3-4:100; the mass ratio of the added mass of tocopherol, titanium dioxide powder and magnesium chloride powder to the polyvinyl alcohol is tocopherol: titanium dioxide powder: magnesium chloride powder: polyvinyl alcohol = 1-2g: 2-3g: 0.6-0.9g: 1-2g.

10. A method for preparing a water-based high-hiding quick-drying white ink according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: S1: Add white ink paste, thermoplastic acrylic resin and functional resin into the reactor in sequence, stir for 20 to 30 minutes until the paste is evenly dispersed, then add wetting agent and dispersant, and continue stirring for 20 to 30 minutes to obtain a crude white ink; S2: Add the defoamer into the remaining deionized water and stir for 10 to 15 minutes, then pour into the crude white ink mixed solution and stir for 20 to 30 minutes to obtain a mixed solution 1; S3: Add a pH adjuster and an antibacterial agent to the mixed solution 1, adjust the pH to 6.0-8.0, stir for 30-60 minutes to obtain a mixed solution 2, filter the mixed solution 2 through a 400-mesh fine mesh twice, and obtain a high-coverage quick-drying white ink.