Preparation and Performance Study of Black Ceramic Ink

With the advancement of science and technology, digital control technology has gained increasing prominence in modern manufacturing industries. Ceramic digital inkjet printing technology, as a form of digital non-contact printing technology, is considered one of the key technologies for industrialization. This study successfully prepared black ceramic ink using a grinding dispersion method and explored the impact of different grinding times on the ink's performance. The results indicate that within 1.5 hours of grinding, black ceramic ink with an average particle size of 200-300nm can be produced, meeting the requirements of inkjet printers.

In contrast to conventional inkjet printing, ceramic inkjet printing ink needs to undergo high-temperature firing after printing. The color effects under different glazes or firing temperatures vary. Ceramic ink, as a core element in inkjet printing technology, refers to a type of liquid found in inkjet printers that contains special ceramic powders, ceramic pigments, or colorants. Generally, ceramic ink is composed of inorganic non-metal pigments (colorants, glazes), solvents, dispersants, surfactants, and other additives. Currently, the main methods of preparing ceramic ink include sol-gel methods, reverse-phase microemulsion methods, and dispersion methods. Sol-gel methods have matured but have the disadvantage of poor stability with high solid content, leading to precipitation over time. Reverse-phase microemulsion methods are costly and not suitable for large-scale production. In contrast, dispersion methods are commonly used, making the ceramic ink process simpler, more cost-effective, and suitable for industrial production due to ongoing improvements in grinding technology.

The preparation of ceramic ink primarily involves two key factors: the stability of ceramic ink, which determines whether color particles can be uniformly dispersed in the ink, and the performance of the ceramic ink to meet the hardware requirements of inkjet printers. This necessitates strict control of performance indicators such as ceramic ink viscosity, density, and particle size. The dispersion of inorganic color pigments in ceramic ink is not a simple powdering process; it requires the uniform and stable distribution of color particles in the medium to prevent aggregation, coagulation, or precipitation. Under different process conditions, the degree of fragmentation of inorganic color pigments varies. Controlling the particle size distribution range of ceramic ink and reducing grinding time poses challenges in the grinding dispersion method. This study investigates black ceramic ink, using the copper oxide black system, and prepares black ceramic ink using the grinding dispersion method. The influence of different grinding times on ink properties, such as particle size, is examined. Through analysis of particle size and zeta potential using a nanosize and zeta potential analyzer and transmission electron microscopy, the study identifies the optimal grinding time for producing high-performance ceramic ink, aiming to reduce energy consumption and enhance industrial economic benefits.

Experimental Section1.1 Experimental Instruments and MaterialsThe experimental instruments and materials used in this study are listed in Table 1.

1.2 Preparation of Black Ceramic InkBlack ceramic ink was prepared using the grinding dispersion method. The specific experimental steps are as follows: in a fixed ratio, mix inorganic pigment Copper Oxide Black, solvent, dispersant 2055, defoamer, and wetting agent Anti-terra-U. Disperse the mixture using a disperser at a speed of 800 revolutions per minute for 30 minutes. Then, divide the ink into five portions and grind the mixtures with zirconium oxide beads for different durations using a sand mill (0.5h, 1h, 1.5h, 2h, and 2.5h). After filtration, the resulting filtrate is the black ceramic ink, which is subsequently subjected to performance testing.

Results and Discussion2.1 Influence of Different Grinding Times on Ceramic Ink PerformanceGrinding time directly affects the particle size of ceramic ink. The choice of the optimal grinding time is a key factor in determining the performance of ceramic ink. Different ceramic ink samples were prepared with varying grinding times. Table 2 shows a comparison of the particle size distribution range of ceramic ink prepared under different grinding times.

Table 2 reveals that under the same solvent proportion, ceramic ink prepared with a 0.5-hour grinding time has a wide particle size distribution range, while ceramic ink prepared with a 1.5-hour grinding time has a narrower distribution range. Within a certain range of grinding time, as the grinding time increases, the particle size distribution range gradually narrows. When the particle size of ceramic ink particles reaches a certain size, further extension of the grinding time does not significantly affect the particle size distribution. Thus, the optimal grinding time for preparing ceramic ink is set at 1.5 hours, resulting in a narrow particle size distribution range that meets the requirements of inkjet printers. Figure 1 demonstrates that, as grinding time increases, the average particle size of coloring particles gradually decreases. Initially, the particle size reduction is rapid, and the particle size decreases from around 82 nm to about 280 nm. With continued grinding, the particle size further reduces, but the rate of reduction decreases, especially after 1.5 hours of grinding when the particle size remains relatively stable. The irregular particle shape of the coloring particles after grinding is due to various forces, such as squeezing and shearing forces, acting on the large particles at the beginning of grinding.

After grinding for 1.5 hours, most of the coloring particles have been broken into smaller particles. Furthermore, the distribution index of particle size decreases with longer grinding times (Figure 2). Initially, multiple peaks are observed, indicating uneven dispersion of coloring particles. After 1.5 hours of grinding, the distribution becomes more uniform and narrower. Beyond 1.5 hours, the distribution index remains mostly unchanged.

2.2 Transmission Electron Microscopy (TEM) Observation of Ceramic Ink DispersionFive groups of black ceramic ink were prepared with a grinding time of 1.5 hours. These were formulated into ink dispersion solutions, and the size and dispersion of coloring particles in the dispersion solution were observed using transmission electron microscopy (TEM), as shown in Figure 3. Figure 3 clearly reveals even distribution of coloring particles in the dispersion solution, with the particles encapsulated by additives, forming individual ink particles dispersed in the solvent. After 0.5 hours of grinding, the coloring particles are larger, with no aggregation. The particle size is approximately around 600 nm. After 1.5 hours of grinding, the previous large particles have been broken down into smaller particles, surrounded by additive molecules. The particles are smaller, with a size below 300 nm. Most of the particles in the ceramic ink have a size between 150-300 nm, with an irregular shape in the range of 200-300 nm. The observations from TEM are consistent with the results obtained from the nanosize and zeta potential analyzer.

2.3 Printing Test of Ceramic InkCeramic ink with a grinding time of 1.5 hours was filled into a CoPilot256 inkjet printer by Guixi Bao Company. The ink was practically printed on white paper, as shown in Figure 4. The image quality demonstrates clear and precise text, vibrant patterns, and colors with no defects such as trailing, air bubbles, streaks, or ink splatters. This confirms that the black ceramic ink prepared with a 1.5-hour grinding time meets the requirements of an inkjet printer.

Conclusion(1) This study successfully prepared high-quality black ceramic ink using the grinding dispersion method, with particle size meeting the requirements of inkjet printers and exhibiting good stability.(2) Experimental results indicate that a grinding time of 1.5 hours can produce black ceramic ink with an average particle size of 200-300 nm and an ideal particle size distribution. This optimal grinding time aims to reduce energy consumption and enhance industrial economic benefits.