In the production and application of inks, the dispersion stability of pigment particles is one of the key factors affecting ink quality. In ultrasonic inks, the anti-settling and dispersion of pigment particles is of particular concern, as it directly relates to ink performance, application effects, and the final quality of the product.
If pigment particles settle in ink, it will lead to many adverse consequences. On the one hand, settling will reduce the color uniformity of the ink, resulting in color differences and color spots in the printed products, seriously affecting the appearance quality of the products. On the other hand, settled pigment particles may clog the nozzles and mesh of printing equipment, causing equipment failure, increasing production costs and downtime. Furthermore, settling will reduce the storage stability of the ink, shorten its shelf life, and cause economic losses to enterprises.
Many factors affect the settling of pigment particles in ultrasonic inks. First, there are the characteristics of the pigment particles themselves, such as particle size, shape, and density. Generally speaking, the larger the particles and the higher the density, the faster the settling speed; however, irregularly shaped particles settle relatively slowly compared to spherical particles because they encounter greater resistance during movement. Secondly, the properties of the ink system also play a crucial role, including ink viscosity, surface tension, and the density of the dispersion medium. Higher ink viscosity results in stronger binding forces on pigment particles, effectively slowing sedimentation. A smaller density difference between the dispersion medium and pigment particles reduces the driving force for sedimentation, further minimizing sedimentation.
Ultrasonic technology demonstrates unique advantages in addressing pigment particle sedimentation. Ultrasonic waves, with frequencies above 20kHz, generate mechanical vibrations and cavitation effects during propagation. Mechanical vibrations strongly agitate the ink system, promoting uniform dispersion of pigment particles and preventing aggregation and sedimentation. Cavitation, on the other hand, refers to the generation of numerous tiny bubbles when ultrasound propagates in a liquid. The instantaneous collapse of these bubbles releases significant energy, creating a localized high-temperature, high-pressure environment that breaks down the agglomeration forces between pigment particles, dispersing large particles into smaller ones and improving dispersion stability.
In practical applications, optimal anti-settling dispersion effects can be achieved by appropriately adjusting ultrasonic parameters such as frequency, power, and processing time. Different types of pigment particles and ink systems require different ultrasonic parameters. For example, denser pigment particles may require higher ultrasonic power and longer processing times to effectively prevent sedimentation.
Besides the ultrasonic technology itself, optimizing the ink formulation also plays a crucial role in preventing pigment particle sedimentation and dispersion. Adding appropriate amounts of dispersants, thickeners, and other additives to the ink formulation can improve the compatibility between pigment particles and the dispersion medium, increase ink viscosity, and further enhance the dispersion stability of pigment particles. This synergistic effect with ultrasonic technology achieves better anti-settling results.
With the continuous development of the printing industry, the requirements for ink quality are becoming increasingly stringent. Ultrasonic ink pigment particle anti-settling and dispersion technology is also constantly being innovated and improved. In the future, through in-depth research into the ultrasonic action mechanism, optimization of process parameters, and development of new additives and formulations, it is expected that the performance of ultrasonic inks can be further improved to meet the needs of different printing fields and promote the sustainable development of the printing industry.
