High-dispersity ceramic ink as well as preparation method and application thereof

Abstract

The invention discloses high-dispersity ceramic ink as well as a preparation method and application thereof, and belongs to the field of ceramic ink. The high-dispersity ceramic ink comprises a ceramic pigment, wherein the ceramic pigment is ZrO2 (at) AlOOH prepared by a sol-gel method; the ZrO2-coated AlOOH takes zirconium dioxide as a core, and the outer layer of the ZrO2-coated AlOOH is coated with boehmite; the mass of the boehmite is 3-5wt% of the mass of the zirconium dioxide. Boehmite as a coating layer can form a hydration shell layer on the surface of zirconium dioxide, restrain agglomeration among particles and improve colloid stability, and boehmite contains more active hydroxyl groups, so that interaction force among ceramic pigments can be further weakened, particle aggregation can be avoided, meanwhile, covering power and whiteness of the ceramic ink can be improved, and the ceramic ink has a good application prospect. The color development performance is improved. The phosphorylated polyether modified silicone oil is adopted as a dispersing agent, the dispersity of the ink can be further improved, and the ceramic ink which is excellent in rheological property and does not settle after being stored for a long time is obtained.

Description

Technical Field

[0001] This invention relates to the field of ceramic inks, and particularly to a highly dispersible ceramic ink, its preparation method, and its application. Background Technology

[0002] Ceramic inkjet printing technology is a non-contact digital printing technology. It involves preparing ceramic ink from ultrafine ceramic pigments and then printing it onto the ceramic surface using an inkjet printer. This process eliminates the need for contact pressing, reducing the damage rate of the blank, greatly simplifying the process, and improving production efficiency. Currently, ceramic inkjet printing technology, with its superior characteristics, is gradually replacing traditional screen printing and roller printing, and is widely used in many fields.

[0003] Ceramic ink, as the core material for ceramic inkjet printing, is typically composed of ceramic pigments, solvents, complexing agents, surfactants, drying agents, dispersants, and other additives. Its excellent stability is crucial for ensuring smooth inkjet printing and high-quality final products. Ceramic pigments, the most essential substance in ceramic ink, are the key component for ink color development. They mainly consist of various metal oxides and inorganic metal salts, and their dispersibility and stability directly determine the stability of the ceramic ink.

[0004] The main methods for preparing ceramic pigments include dispersion, sol-gel and reverse microemulsion methods. Among them, dispersion is the most commonly used method, but the purity of the finished product is low, energy consumption is high and particle agglomeration is very easy to occur. Reverse microemulsion method can produce highly dispersible inks, but the solid content is low and the production cost is high.

[0005] The sol-gel method involves the hydrolysis and condensation of metal salts or hydroxides to form stable sol particles. Sols are chemically synthesized alternating particle dispersion systems that help disperse particles more evenly, avoiding the drawbacks of mechanical grinding. They retain good color rendering even after heat treatment and can produce a variety of ceramic inks. For example, hydrolyzing aluminum isopropylidene hydrate to prepare an alumina sol, then adding boric acid and nickel oxide in a specific ratio and continuously stirring with a magnetic stirrer, can produce cyan ceramic ink; adding zinc nitrate, chromium nitrate, and boric acid in a specific ratio produces magenta ceramic ink; using zirconium salts as the zirconium ion source to prepare zirconium dioxide via the sol-gel method can produce white ceramic ink for inkjet printing, and so on. However, because sols are thermodynamically unstable systems, they are prone to sedimentation after prolonged standing, resulting in a short shelf life for ceramic inks and ink dripping or nozzle clogging during printing, affecting color rendering. Summary of the Invention

[0006] This invention provides a highly dispersible ceramic ink, its preparation method, and its application, which can solve the problems of poor dispersibility and easy sedimentation in existing ceramic inks.

[0007] In a first aspect, the present invention provides a highly dispersible ceramic ink, comprising a ceramic pigment, wherein the ceramic pigment is ZrO2@AlOOH prepared by the sol-gel method; ZrO2@AlOOH has a zirconium dioxide core and is coated with boehmite on the outside; Boehmite weighs 3 to 5 wt% of zirconium dioxide.

[0008] This invention employs a sol-gel method to obtain white ceramic pigments with uniform particle size, small pigment particles, and narrow particle size distribution. The obtained ceramic pigments use zirconium dioxide as the core layer and boehmite as the shell layer. The boehmite as the coating layer can form a hydrated shell layer on the zirconium dioxide surface. The steric hindrance effect can directly block the direct contact between the zirconium dioxide core layer, thereby inhibiting the agglomeration between zirconium dioxide particles, improving the dispersibility of the ceramic pigments, and also improving the stability of the colloid.

[0009] Furthermore, since boehmite has a lower density than zirconium dioxide, the density of the composite material ZrO2@AlOOH formed after coating is lower than that of zirconium dioxide, which can reduce the settling rate of ceramic pigments. In addition, the gel network structure formed between the boehmite shells can increase the thixotropy of ceramic inks. During long-term static storage, it can prevent particle settling by forming a weak gel network, thereby greatly improving the anti-settling performance of ceramic inks.

[0010] Meanwhile, this invention selects boehmite as the outer coating layer. On the one hand, compared with other coating materials such as alumina, boehmite has more active hydroxyl groups, which can interact with other organic additives in ceramic ink to form an organic coating layer on the outside of ceramic pigment particles, further weakening the interaction force between ceramic pigments and preventing particle aggregation.

[0011] On the other hand, insufficient whiteness and opacity of ceramic inks, especially white ceramic inks, can affect the performance of ceramic inks, preventing the colors and patterns from achieving optimal results. Ceramic pigments obtained after boehmite coating can form a gradient refractive interface through the difference in refractive index, thereby improving the scattering efficiency of visible light and enhancing the opacity of ceramic inks. Furthermore, by coating and filling the surface of zirconium dioxide particles, light absorption defects are reduced, thereby improving the whiteness of the ceramic ink of this invention.

[0012] Preferably, the raw materials for ZrO2@AlOOH include zirconium oxychloride and anhydrous aluminum chloride in a mass ratio of 1:(0.04-0.08).

[0013] Preferably, ZrO2@AlOOH is prepared according to the following method: S1. Add zirconium oxychloride to water, stir to dissolve, adjust the solution temperature to 70-75℃, add ammonia water dropwise, and let stand at a constant temperature for 2-3 hours to obtain a sol. After washing, dry at 80-100℃, grind, and finally calcine at 600-650℃ to obtain pretreated zirconium dioxide. S2. Anhydrous aluminum chloride is added to an alcohol solvent to prepare an anhydrous aluminum chloride solution with a concentration of 0.2-0.4 mol / L; pretreated zirconium dioxide is dispersed in water, and after adding a dispersant, the mixture is stirred to obtain a zirconium dioxide suspension with a concentration of 0.3-0.5 mol / L. S3. Mix anhydrous aluminum chloride solution and zirconium dioxide suspension, stir for 1-2 hours, filter and wash, then add to a dilute ammonia solution with a concentration of 0.02-0.04 mol / L for 1-2 hours, finally wash, and heat-treat at 300-350℃ to obtain the final product.

[0014] Preferably, in step S1, the mass ratio of ammonia to zirconium oxychloride is (0.4-0.45):1; in step S2, the amount of dispersant added is 0.2-0.5 wt% of the mass of the pretreated zirconium dioxide; the dispersant includes polyacrylamide.

[0015] Preferably, the drying temperature in step S1 is 80-100℃ and the calcination temperature is 600-650℃; the heat treatment temperature in step S3 is 300-350℃.

[0016] More preferably, the alcohol solvent includes ethanol and methanol.

[0017] By employing the above technical solution, after zirconium oxychloride is dissolved in water and ammonia is added dropwise, the degree of polymerization of the resulting zirconium hydroxide colloid gradually increases, forming a polymer linked by cross-linked and non-cross-linked hydroxyl groups. Then, through drying and calcination, the free and adsorbed water in the colloid gradually disappears, the hydroxyl groups dehydrate, and finally crystallize to form pretreated zirconium dioxide.

[0018] Anhydrous aluminum chloride solution was then added to the zirconium dioxide suspension, and adsorption and complexation occurred on the zirconium dioxide surface. Under the action of the active functional groups on the zirconium dioxide surface, aluminum chloride gradually adsorbed and formed nuclei on the zirconium dioxide surface. After washing, the zirconium dioxide was soaked in dilute ammonia water. The aluminum chloride adsorbed on the zirconium dioxide surface underwent multiple hydrolysis reactions and gradually formed boehmite. After hydrolysis, the boehmite was finally coated on the zirconium dioxide surface. Then, after heat treatment, the adsorbed water in the boehmite could be removed to obtain ZrO2@AlOOH.

[0019] The composite material ZrO2@AlOOH, after being coated, can retain the fine and uniform characteristics of ceramic pigment particles prepared by the sol-gel method, while greatly improving the dispersibility and anti-settling properties of ceramic pigments in ceramic inks. It can also improve the whiteness and opacity of white ceramic inks through the coating of boehmite.

[0020] Preferably, ZrO2@AlOOH is also surface modified with hydroxypropyl-β-cyclodextrin; Surface modification treatment specifically includes the following steps: Hydroxypropyl-β-cyclodextrin is dissolved in water, then ZrO2@AlOOH is added and stirred to disperse. The temperature is raised to 50-60℃ and stirred for 4-6 hours to obtain the product. The mass ratio of hydroxypropyl-β-cyclodextrin to ZrO2@AlOOH is (0.02~0.04):1.

[0021] By employing the above technical solution, this invention improves the dispersibility of ceramic pigments by coating the zirconium dioxide surface with boehmite to introduce a large number of active hydroxyl groups, thereby reducing particle agglomeration and lowering the probability of sedimentation. However, the boehmite shell undergoes a phase transformation at higher sintering temperatures, leading to shell cracking or core-shell separation, thus disrupting the integrity of the core-shell structure. Furthermore, the uneven shrinkage of the boehmite shell itself further affects the stability of the ceramic pigment, ultimately resulting in a shortened shelf life of the obtained ceramic ink. The damage to the core-shell structure reduces light scattering efficiency and decreases white opacity.

[0022] To further obtain structurally stable ZrO2@AlOOH ceramic pigments, this invention also performs surface modification treatment on ZrO2@AlOOH. During the modification process, hydroxypropyl-β-cyclodextrin, due to its unique structural characteristics, contains a hydrophilic outer surface and a hydrophobic cavity, forming a special three-dimensional ring structure that can match the nanoscale pore size in the boehmite coating layer. One end of the hydroxypropyl-β-cyclodextrin molecular chain is embedded in its pores, forming a mechanically interlocked binding structure. This not only allows the hydroxyl groups of hydroxypropyl-β-cyclodextrin to construct a secondary hydration layer, forming a denser, stronger, and more stable outer coating layer on the zirconium dioxide surface, but also does not consume the active hydroxyl groups of the original boehmite shell. After surface modification, not only is the stability of the boehmite shell layer enhanced, but the dispersibility of the ceramic pigment is also improved, pigment agglomeration is reduced, thereby extending the shelf life of the ceramic ink and improving its performance.

[0023] Meanwhile, after surface modification, hydroxypropyl-β-cyclodextrin can form a transparent film, establishing a refractive index transition layer between the original high-refractive-index ceramic pigment particles and the low-refractive-index matrix. This structure can reduce ineffective scattering of light on the surface of individual particles, enabling more effective scattering and refraction, which can be macroscopically manifested as higher hiding power.

[0024] Preferably, the highly dispersible ceramic ink comprises the following raw materials in parts by weight: ZrO2@AlOOH 20-30 parts; 3-5 parts of phosphorylated polyether modified silicone oil; 0.5 to 1 part adhesive; 0.3 to 0.5 parts of defoamer; Solvent 30-50 parts.

[0025] More preferably, the adhesive includes any one of acrylic resin, polyvinyl alcohol, polyvinyl butyral, and polyvinylpyrrolidone.

[0026] More preferably, the defoamer includes any one of defoamer BYK-019, defoamer BYK-052, defoamer BYK-065, defoamer BYK-088 and defoamer BYK-093.

[0027] More preferably, the solvent includes any one of deionized water, propylene glycol, ethanol, n-pentanol, ethylene glycol, dimethylformamide, and n-hexane.

[0028] By adopting the above technical solution, the ceramic ink of the present invention selects phosphorylated polyether-modified silicone oil as the main dispersant. The good hydrophilicity of the polyether segments, combined with the good hydrophobicity of the silicone oil, allows the amphiphilic segments to be highly compatible with the ceramic ink solvent, forming a hydrated shell and increasing the effective diameter of the ceramic pigment, thereby reducing the probability of collision between ceramic pigment particles. On the other hand, it can help reduce the surface tension of the ceramic ink and improve inkjet printing performance. The amphiphilic block structure of the polyether-modified silicone oil also endows the ceramic ink with shear-thinning properties, which can form a gel network with the ceramic pigment when standing, preventing sedimentation and extending the shelf life of the ceramic ink.

[0029] Furthermore, after phosphorylation modification, it can form strong coordination bonds with the active groups on the boehmite surface of ZrO2@AlOOH, improving the binding strength with ceramic pigments and achieving multi-point anchoring adsorption. Moreover, the negative charge of the phosphate groups can eliminate the electrostatic attraction between ceramic pigment particles, increase the repulsive force, break up micelle aggregation, release the encapsulated free water, improve the rheological properties of the ceramic ink, and obtain a ceramic ink with excellent rheological properties that does not settle during long-term storage.

[0030] Furthermore, after ZrO2@AlOOH undergoes surface modification, the phosphorylated polyether modified silicone oil can interact with hydroxypropyl-β-cyclodextrin. The cavities contained in hydroxypropyl-β-cyclodextrin can contain the hydrophobic linkages of the silicone oil, forming inclusion complexes. This enhances the anchoring ability between the phosphorylated polyether modified silicone oil and ceramic pigments, allowing them to be more firmly fixed to the surface of the ceramic pigments, maintaining the stability of the dispersion system, optimizing the dispersion effect, and thus significantly improving the storage stability of ceramic inks.

[0031] Preferably, the raw materials for the phosphorylated polyether modified silicone oil include polyether modified silicone oil, phosphorus pentoxide, and water in a molar ratio of 1:(0.5-0.6):(0.4-0.5).

[0032] More preferably, the molecular weight of the polyether-modified silicone oil is 500 to 3000.

[0033] Preferably, the phosphorylated polyether modified silicone oil is prepared according to the following method: A reducing agent is added to polyether-modified silicone oil and the temperature is adjusted to 50-60℃. Phosphorus pentoxide is added, the temperature is raised to 70-80℃, and the mixture is stirred for 3-4 hours. Then water is added, and the mixture is stirred for another 3-4 hours to obtain the pretreated product. The pretreated product is added to toluene and the temperature is adjusted to 50-60℃. An alkaline aqueous solution is added, and the mixture is reacted at a constant temperature for 1-2 hours. Toluene is then removed by vacuum distillation, and the product is then concentrated under vacuum to obtain the final product.

[0034] More preferably, the reducing agent is phosphorous acid; the amount of reducing agent added is 0.2 to 0.5 wt% of the mass of the polyether modified silicone oil.

[0035] More preferably, the alkaline aqueous solution includes any one of sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, ammonia solution, and sodium carbonate aqueous solution.

[0036] By adopting the above technical solution, phosphorus pentoxide, as a phosphorylation aid, can undergo a phosphorylation reaction with the hydroxyl groups in polyether-modified silicone oil. After hydrolysis, a stable structure of phosphate ester is gradually formed, and then the phosphorylated polyether-modified silicone oil is obtained by neutralization with alkali solution.

[0037] Phosphorylation treatment utilizes the negative charge to eliminate electrostatic attraction between ceramic pigments, thereby further promoting the dispersibility and anti-settling properties of ceramic pigments. Moreover, compared to general phosphate dispersants, this invention phosphorylates polyether-modified silicone oil. The amphiphilic block structure of polyether-modified silicone oil not only has good compatibility with solvents but also reduces the surface tension of ceramic inks, which can further help prevent sedimentation.

[0038] Secondly, the present invention provides a method for preparing a highly dispersible ceramic ink, comprising the following process steps: Weigh the raw materials for the highly dispersible ceramic ink according to the corresponding mass proportions, mix them evenly, ball mill and disperse for 5-8 hours, and then filter to obtain the highly dispersible ceramic ink.

[0039] More preferably, filtration is performed through a filter membrane with a thickness of 0.8 to 1.0 μm.

[0040] Thirdly, the present invention provides an application of a highly dispersible ceramic ink, which can be used for inkjet printing of ceramic products.

[0041] The beneficial effects of this invention are: 1. This invention provides a highly dispersible ceramic ink, in which the ceramic pigment is ZrO2@AlOOH. Boehmite, as a coating layer, can form a hydrated shell on the zirconium dioxide surface, inhibiting particle aggregation and improving colloidal stability. Furthermore, it can reduce the overall density, increase the thixotropy of the ceramic ink, prevent particle sedimentation, and improve dispersibility. Compared to general coating layers, boehmite contains more active hydroxyl groups, which can interact with other organic additives in the ceramic ink to form an organic coating layer on the outside of the ceramic pigment particles, further weakening the interaction forces between the ceramic pigments and preventing particle aggregation.

[0042] Meanwhile, the zirconium dioxide coated with boehmite can increase the hiding power of ceramic ink, reduce light absorption defects, improve the whiteness of the ceramic ink of this invention, and enhance the color rendering performance of ceramic ink.

[0043] 2. This invention provides a highly dispersible ceramic ink that uses phosphorylated polyether-modified silicone oil as a dispersant. Its amphiphilic segments are highly compatible with the ceramic ink solvent, forming a hydrated shell and reducing the probability of collisions between ceramic pigment particles. Furthermore, it helps reduce the surface tension of the ceramic ink, improving inkjet printing performance. Phosphorylation modification also eliminates electrostatic attraction between ceramic pigment particles, increases repulsion, breaks up agglomerates, releases encapsulated free water, and improves the rheological properties of the ceramic ink, resulting in a ceramic ink with excellent rheological properties that does not settle during long-term storage. Detailed Implementation

[0044] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0045] Preparation Example 1 Preparation Example 1-1: A ZrO2@AlOOH compound was prepared according to the following method: S1. Add 10g of zirconium oxychloride to water, stir to dissolve, and prepare a 0.5mol / L zirconium oxychloride aqueous solution. Adjust the solution temperature to 75℃, add 4g of ammonia water dropwise, and let it stand at a constant temperature for 2h to obtain a sol. Wash it alternately with distilled water and anhydrous ethanol, dry it at 100℃ for 3h, grind it, and calcine it at 650℃ for 3h to obtain pretreated zirconium dioxide. S2. Add 0.6 g of anhydrous aluminum chloride to ethanol to prepare an anhydrous aluminum chloride solution with a concentration of 0.3 mol / L; disperse the pretreated zirconium dioxide obtained above in water, add polyacrylamide and stir to mix, wherein the amount of polyacrylamide added is 0.2 wt% of the mass of the pretreated zirconium dioxide, and finally obtain a zirconium dioxide suspension with a concentration of 0.4 mol / L. S3. Mix the anhydrous aluminum chloride solution and zirconium dioxide suspension obtained above, stir for 1 hour, filter and wash, then add to a 0.04 mol / L dilute ammonia solution for 2 hours, finally wash, and heat-treat at 300℃ for 4 hours to obtain the final product.

[0046] Preparation Example 1-2, a ZrO2@AlOOH, differs from Preparation Example 1-1 only in that the amount of anhydrous aluminum chloride added is 0.4 g.

[0047] Preparation Examples 1-3, a ZrO2@AlOOH, differs from Preparation Example 1-1 only in that the amount of anhydrous aluminum chloride added is 0.8 g.

[0048] Preparation Examples 1-4, a ZrO2@AlOOH, differs from Preparation Example 1-1 only in that the amount of anhydrous aluminum chloride added is 0.2 g.

[0049] Preparation Examples 1-5, a ZrO2@AlOOH, differs from Preparation Example 1-1 only in that the amount of anhydrous aluminum chloride added is 1g.

[0050] Preparation Examples 1-6: A ZrO2@Al2O3 was prepared according to the following method: S1. Add 10g of zirconium oxychloride to water, stir to dissolve, and prepare a 0.5mol / L zirconium oxychloride aqueous solution. Adjust the solution temperature to 75℃, add 4g of ammonia water dropwise, and let it stand at a constant temperature for 2h to obtain a sol. Wash it alternately with distilled water and anhydrous ethanol, dry it at 100℃ for 3h, and then grind it and calcine it at 650℃ to obtain pretreated zirconium dioxide. S2. Add 0.6 g of anhydrous aluminum chloride to ethanol to prepare an anhydrous aluminum chloride solution with a concentration of 0.3 mol / L; disperse the pretreated zirconium dioxide obtained above in water, add polyacrylamide and stir to mix, wherein the amount of polyacrylamide added is 0.2 wt% of the mass of the pretreated zirconium dioxide, and finally obtain a zirconium dioxide suspension with a concentration of 0.4 mol / L. S3. Mix the anhydrous aluminum chloride solution and zirconium dioxide suspension obtained above, stir for 2 hours, wash, and then heat treat at 300°C for 4 hours to obtain the final product.

[0051] Preparation Examples 1-7: A ZrO2 was prepared according to the following method: S1. Add 10g of zirconium oxychloride to water, stir to dissolve, and prepare a 0.5mol / L zirconium oxychloride aqueous solution. Adjust the solution temperature to 75℃, add 4g of ammonia water dropwise, and let it stand at a constant temperature for 2h to obtain a sol. Wash it alternately with distilled water and anhydrous ethanol, dry it at 100℃ for 3h, then grind it and calcine it at 650℃ for 3h to obtain the final product.

[0052] Preparation Examples 1-8, a ZrO2@AlOOH, differs from Preparation Example 1-1 only in that it undergoes surface modification treatment, specifically including: Dissolve 0.3g of hydroxypropyl-β-cyclodextrin in water, then add 10g of ZrO2@AlOOH prepared in Preparation Example 1-1- and stir to disperse. Increase the temperature to 60℃ and stir for 4 hours to obtain the final product.

[0053] Preparation Example 2 Preparation Example 2-1: A phosphorylated polyether modified silicone oil was prepared according to the following method: Add 0.3 wt% phosphorous acid to polyether-modified silicone oil (average molecular weight of 1500) and adjust the temperature to 60°C. Add phosphorus pentoxide, raise the temperature to 80°C, and stir for 3 hours. Then add water and continue stirring for 3 hours to obtain the pretreated product. The molar ratio of polyether-modified silicone oil, phosphorus pentoxide and water is 1:0.5:0.5. The pretreated material was added to toluene and the temperature was adjusted to 60°C. A 25% sodium hydroxide aqueous solution was added and the mixture was reacted at a constant temperature for 2 hours. Toluene was then removed by vacuum distillation and the product was concentrated under vacuum at a vacuum degree of 0.1 MPa and a concentration temperature of 90°C.

[0054] Example Example 1: A highly dispersible ceramic ink was prepared according to the following method: Weigh out 25 parts of ZrO2@AlOOH prepared in Preparation Example 1-1, 4 parts of phosphorylated polyether modified silicone oil prepared in Preparation Example 2-1, 0.8 parts of polyvinyl alcohol, 0.4 parts of defoamer BYK-019 and 40 parts of solvent, wherein the solvent includes ethanol and water in a mass ratio of 2:1. After mixing the above raw materials evenly, the mixture is ball-milled and dispersed for 6 hours, and then filtered through a 0.8 μm filter membrane to obtain highly dispersible ceramic ink.

[0055] Examples 2 and 3 describe a highly dispersible ceramic ink, differing from Example 1 only in the adjustment of the raw material ratio, as shown in Table 1: Table 1. Formulations for Examples 1 to 3

[0056] In both Examples 2 and 3, ZrO2@AlOOH prepared in Preparation Example 1-1 was used.

[0057] Example 4, a highly dispersible ceramic ink, differs from Example 1 only in that an equal amount of ZrO2@AlOOH prepared in Preparation Example 1-1 is used instead of ZrO2@AlOOH prepared in Preparation Example 1-2.

[0058] Example 5, a highly dispersible ceramic ink, differs from Example 1 only in that an equal amount of ZrO2@AlOOH prepared in Preparation Examples 1-3 is used instead of ZrO2@AlOOH prepared in Preparation Examples 1-1.

[0059] Example 6, a highly dispersible ceramic ink, differs from Example 1 only in that an equal amount of ZrO2@AlOOH prepared in Preparation Examples 1-8 is used instead of ZrO2@AlOOH prepared in Preparation Examples 1-1.

[0060] Example 7, a highly dispersible ceramic ink, differs from Example 1 only in that the amount of phosphorylated polyether modified silicone oil obtained in Preparation Example 2-1 added is 1 part.

[0061] Example 8, a highly dispersible ceramic ink, differs from Example 1 only in that the amount of phosphorylated polyether modified silicone oil obtained in Preparation Example 2-1 added is 8 parts.

[0062] Example 9, a highly dispersible ceramic ink, differs from Example 1 only in that an equal amount of polyether-modified silicone oil is used to replace the phosphorylated polyether-modified silicone oil prepared in Preparation Example 2-1.

[0063] Example 10, a highly dispersible ceramic ink, differs from Example 1 only in that an equal amount of sodium tripolyphosphate is used to replace the phosphorylated polyether modified silicone oil prepared in Preparation Example 2-1.

[0064] Comparative Example Comparative Example 1 is a highly dispersible ceramic ink, which differs from Example 1 only in that an equal amount of ZrO2@AlOOH prepared in Preparation Examples 1-4 is used instead of ZrO2@AlOOH prepared in Preparation Example 1-1.

[0065] Comparative Example 2, a highly dispersible ceramic ink, differs from Example 1 only in that an equal amount of ZrO2@AlOOH prepared in Preparation Examples 1-5 is used instead of ZrO2@AlOOH prepared in Preparation Example 1-1.

[0066] Comparative Example 3, a highly dispersible ceramic ink, differs from Example 1 only in that an equal amount of ZrO2@Al2O3 prepared in Preparation Examples 1-6 is used to replace the ZrO2@AlOOH prepared in Preparation Example 1-1.

[0067] Comparative Example 4, a highly dispersible ceramic ink, differs from Example 1 only in that an equal amount of ZrO2 prepared in Preparation Examples 1-7 is used to replace the ZrO2@AlOOH prepared in Preparation Example 1-1.

[0068] Performance testing 1. Color Development Performance Test: Using the ceramic inks obtained in the examples and comparative examples, a domestically produced wide-format printer was used, equipped with a UV curing lamp with a wavelength of 395nm, and a Ricoh MH5420 fifth-generation industrial printhead. The whiteness and opacity of the printed color blocks were measured using a whiteness meter. 2. Anti-settling performance test: 25 mL of the ceramic ink obtained in the examples and comparative examples was placed in a 30 mL glass jar and left to stand in a 50°C oven for 10 days. Then, the ceramic ink in the glass jar was poured out, and the jar was inverted for 10 minutes. The amount of ink remaining in the glass jar was measured, and the sedimentation rate was calculated. Specifically: .

[0069] The results of the above experiments are shown in Table 2: Table 2 Performance test results

[0070] According to Table 2, combined with Examples 1 and 6, it can be seen that the coverage rate of Example 6 is higher than that of Example 1, while the sedimentation rate is lower. The reason is that ZrO2@AlOOH in Example 6 has undergone surface modification treatment. The structural characteristics of hydroxypropyl-β-cyclodextrin enable it to effectively penetrate into the pores of the boehmite shell, forming a mechanically interlocked structure. It does not consume the active hydroxyl groups on the original surface of the boehmite shell. Moreover, by forming a secondary hydration layer, it can significantly inhibit the dehydration of boehmite and the shrinkage of the hydration layer, effectively improve the stability of the hydration layer, further enhance the overall anti-settling performance, and also improve the coverage rate.

[0071] Combining Examples 1, 9, and 10, it can be seen that the sedimentation rates of Examples 9 and 10 are higher than those of Example 1. This is because the polyether-modified silicone oil in Example 9 was not phosphorylated, which weakens the bond between the dispersant polyether-modified silicone oil and the ceramic pigments. Furthermore, the lack of phosphate groups reduces the regulation of electrostatic attraction between ceramic pigments, resulting in decreased dispersibility and anti-settling performance of the ceramic ink. In Example 10, a conventional phosphate dispersant was used, which lacks the amphiphilic chain segment regulation effect of the polyether-modified silicone oil in this invention, thus increasing the collision probability between ceramic pigment particles and reducing anti-settling performance.

[0072] Based on Examples 1, 2, and 4, it can be seen that the color development and anti-settling properties of Comparative Examples 1, 2, and 4 are all lower than those of Example 1. This is because the boehmite content on the surface of ZrO2@AlOOH added in Comparative Example 1 is lower than that in Example 1. This leads to uneven coating, with some zirconium dioxide still exposed, reducing steric hindrance. It also reduces the content of active hydroxyl groups on the ZrO2@AlOOH surface, weakening the binding force with other organic additives in the ceramic ink. Consequently, both the color development and anti-settling properties of the material are reduced. Comparative Example 4 uses uncoated zirconium dioxide, resulting in a significant decrease in color development. In Comparative Example 2, the mass of boehmite on the ZrO2@AlOOH surface is increased compared to Example 1. An excessively thick shell layer leads to larger ceramic pigment particles, resulting in decreased dispersion stability of the ceramic ink. The particles not only have reduced dispersibility but also tend to settle.

[0073] Combining Example 1 and Comparative Example 3, it can be seen that the color development performance and anti-settling performance of Comparative Example 3 are lower than those of Example 1. The reason is that the zirconium dioxide surface in Comparative Example 3 is coated with alumina. Compared with boehmite, alumina contains a much smaller number of active hydroxyl groups, which is not only not conducive to the formation of a hydrated shell, but also reduces the synergistic effect with other organic additives in the ceramic ink. As a result, the overall dispersion stability, color development performance and anti-settling performance of the final ceramic ink are reduced.

[0074] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A highly dispersible ceramic ink, comprising ceramic pigments, characterized in that, The ceramic colorant is ZrO2@AlOOH prepared by the sol-gel method; The ZrO2@AlOOH has zirconium dioxide as its core and boehmite as its outer layer; The boehmite content is 3 to 5 wt% of the zirconium dioxide content.

2. The highly dispersible ceramic ink according to claim 1, characterized in that, The raw materials for ZrO2@AlOOH include zirconium oxychloride and anhydrous aluminum chloride in a mass ratio of 1:(0.04-0.08).

3. The highly dispersible ceramic ink according to claim 2, characterized in that, The ZrO2@AlOOH was prepared according to the following method: S1. Add zirconium oxychloride to water, stir to dissolve, adjust the solution temperature to 70-75℃, add ammonia water dropwise, and let stand at a constant temperature for 2-3 hours to obtain a sol. After washing, dry at 80-100℃, grind, and finally calcine at 600-650℃ to obtain pretreated zirconium dioxide. S2. Add anhydrous aluminum chloride to an alcohol solvent to prepare an anhydrous aluminum chloride solution with a concentration of 0.2-0.4 mol / L; Pretreated zirconium dioxide was dispersed in water, and after adding a dispersant, the mixture was stirred to obtain a zirconium dioxide suspension with a concentration of 0.3–0.5 mol / L. S3. Mix anhydrous aluminum chloride solution and zirconium dioxide suspension, stir for 1-2 hours, filter and wash, then add to a dilute ammonia solution with a concentration of 0.02-0.04 mol / L for 1-2 hours, finally wash, and heat-treat at 300-350℃ to obtain the final product.

4. The highly dispersible ceramic ink according to claim 3, characterized in that, In step S1, the mass ratio of ammonia to zirconium oxychloride is (0.4-0.45):1; in step S2, the amount of dispersant added is 0.2-0.5 wt% of the mass of the pretreated zirconium dioxide; the dispersant includes polyacrylamide.

5. The highly dispersible ceramic ink according to claim 1, characterized in that, The ZrO2@AlOOH has also undergone surface modification treatment with hydroxypropyl-β-cyclodextrin; The surface modification treatment specifically includes the following steps: Hydroxypropyl-β-cyclodextrin is dissolved in water, then ZrO2@AlOOH is added and stirred to disperse. The temperature is raised to 50-60℃ and stirred for 4-6 hours to obtain the product. The mass ratio of the hydroxypropyl-β-cyclodextrin to ZrO2@AlOOH is (0.02~0.04):

1.

6. The highly dispersible ceramic ink according to any one of claims 1 and 5, characterized in that, The highly dispersible ceramic ink comprises the following raw materials in parts by weight: ZrO2@AlOOH 20-30 parts; 3-5 parts of phosphorylated polyether modified silicone oil; 0.5 to 1 part adhesive; 0.3 to 0.5 parts of defoamer; Solvent 30-50 parts.

7. The highly dispersible ceramic ink according to claim 6, characterized in that, The raw materials for the phosphorylated polyether modified silicone oil include polyether modified silicone oil, phosphorus pentoxide, and water in a molar ratio of 1:(0.5-0.6):(0.4-0.5).

8. The highly dispersible ceramic ink according to claim 7, characterized in that, The phosphorylated polyether modified silicone oil was prepared according to the following method: A reducing agent is added to polyether-modified silicone oil and the temperature is adjusted to 50-60℃. Phosphorus pentoxide is added, the temperature is raised to 70-80℃, and the mixture is stirred for 3-4 hours. Then water is added, and the mixture is stirred for another 3-4 hours to obtain the pretreated product. The pretreated product is added to toluene and the temperature is adjusted to 50-60℃. An alkaline aqueous solution is added, and the mixture is reacted at a constant temperature for 1-2 hours. Toluene is then removed by vacuum distillation, and the product is then concentrated under vacuum to obtain the final product.

9. A method for preparing a highly dispersible ceramic ink, used to prepare the highly dispersible ceramic ink according to any one of claims 1 to 8, characterized in that, The process includes the following steps: Weigh the raw materials for the highly dispersible ceramic ink according to the corresponding mass proportions, mix them evenly, ball mill and disperse for 5-8 hours, and then filter to obtain the highly dispersible ceramic ink.

10. An application of a highly dispersible ceramic ink, characterized in that, The highly dispersible ceramic ink according to any one of claims 1 to 8 can be used for inkjet printing of ceramic products.

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