As a material widely used in plastic coloring, masterbatch's pigment dispersion technology plays a key role in product quality and performance. In recent years, research progress has been made in this field in many aspects.
First, continuous innovation in mechanical dispersion technology. Traditional twin-screw extruders are still common equipment for masterbatch production, and the pigment dispersion effect is improved by optimizing the screw structure design. For example, special screw elements and mixing elements are developed to enable pigments to better break up agglomerates under high shear force and evenly disperse them in the carrier resin. In recent years, new co-rotating twin-screw extruders have been widely used. They have higher speeds and more precise temperature control capabilities, can provide a stronger and more uniform shear field, and effectively improve the efficiency and uniformity of pigment dispersion. At the same time, some companies have begun to use micro-nano manufacturing technology to treat the screw surface, such as preparing micro-nano structure coatings on the screw surface, to further enhance the shear and dispersion of pigments and reduce the residual agglomeration of pigment particles.
Secondly, breakthroughs have been made in the research and development and application of chemical dispersants. Various types of high-efficiency dispersants continue to emerge, such as polymer dispersants and super dispersants. Through its special molecular structure, polymer dispersants have a strong affinity with pigment particles at one end and can be adsorbed on the surface of the pigment, and the other end has good compatibility with the carrier resin, thus playing a bridging role between the pigment and the resin and promoting the dispersion of the pigment. Superdispersants have more excellent dispersing properties. They can form a more stable and uniformly thick adsorption layer on the surface of the pigment, significantly reducing the attraction between the pigment particles, so that the pigment can achieve a good dispersion effect under a lower shear force. In addition, dispersants with different structures and properties can be customized through molecular design to meet the needs of different pigments and resin systems, greatly improving the pigment dispersion quality and color stability of masterbatch.
Furthermore, ultrasonic dispersion technology is gradually emerging. The principle of ultrasound application in masterbatch production is to use the cavitation effect of ultrasound to generate a local high temperature and high pressure environment and strong mechanical vibration, so that the pigment agglomerates are broken and dispersed under such extreme conditions. Studies have found that the reasonable selection of ultrasonic frequency, power and action time can effectively improve the dispersion of pigments without introducing too much additional shear force. For example, in some temperature-sensitive pigment systems, ultrasonic dispersion can avoid the problem of pigment discoloration or performance degradation caused by excessive temperature generated by traditional mechanical shearing, providing a new, gentler and more efficient pigment dispersion method for masterbatch production, especially suitable for the preparation of high-quality and high-performance masterbatch products.
Finally, with the development of nanotechnology, the dispersion of nanopigments has become a research hotspot. Nanopigments have unique optical, electrical and other properties, but due to their small particle size and large specific surface area, they are very easy to agglomerate. At present, researchers use a variety of methods to synergistically solve the dispersion problem of nanopigments. On the one hand, the above-mentioned mechanical dispersion, chemical dispersion and other technical means are used; on the other hand, nanopigments are pretreated by surface modification technology, such as grafting organic functional groups on the surface of nanopigments to improve their compatibility with dispersants and carrier resins, so as to achieve uniform and stable dispersion of nanopigments in masterbatch, laying the foundation for the development of masterbatch products with special functions and excellent performance, and promoting the application and expansion of masterbatch technology in the field of high-end plastic processing.
