CNT disperser for continuous dispersion of nanomaterials.

In dispersion processes, the occurrence of agglomerates (clumps) during powder addition, which cannot be resolved in subsequent dispersion stages, is a common issue in many settings. The cause of this is that the powder does not wet uniformly in the liquid, leading to the formation of localized high-concentration areas. These agglomerates are also referred to as "fisheyes," and due to their internal unwetted structure, they are difficult to break apart. Once an agglomerate forms during powder addition, liquid has difficulty penetrating its interior, resulting in only the outer layer being wetted, which makes it hard for the internal particles to be disintegrated. Additionally, depending on the addition position and speed, the powder may float on the liquid surface or remain stagnant without following the flow within the equipment, promoting the formation of agglomerates. Particularly under conditions of high viscosity or high solid content, the low fluidity makes it challenging to achieve uniformity in the initial dispersion stage, leading to a higher likelihood of agglomerates remaining. Such agglomerates may not be completely resolved even with strong shear in subsequent processes, causing variations in the quality of the final product and introducing foreign substances. To prevent the formation of agglomerates, it is crucial to improve wettability during powder addition, ensure appropriate addition positions and flow design, and optimize the initial dispersion. By performing shear and mixing simultaneously right after addition, as in inline powder addition and simultaneous dispersion, it is possible to suppress the formation of agglomerates and achieve stable dispersion quality.

In low bulk density powders and fine powders, issues such as "unstable supply," "pulsation," and "bridging without falling" frequently occur. Particularly with CNTs, carbon black, and flake powders, the particles tend to entangle easily and have low flowability, making stable quantitative supply difficult with conventional powder feeding methods. When powder supply becomes unstable, instantaneous concentration fluctuations occur, significantly affecting the dispersion quality, viscosity, and conductivity in subsequent processes. In practice, even problems that appear to be "poor dispersion" often have their causes on the powder supply side. Moreover, in low bulk density powders, bridging, rat-holing, and supply pulsations due to air entrapment are likely to occur within the hopper, and simply relying on feeder capacity may not resolve these issues. To achieve stable supply, it is crucial to design the entire process, including hopper design, supply methods, transport conditions, and feeding methods, according to the characteristics of the powder. Our company offers a solid-liquid mixing process that includes quantitative supply using loss-in-weight feeders and integration with inline dispersion devices. By designing the entire process from powder supply to dispersion as a cohesive unit, we support the establishment of stable manufacturing conditions even for high-performance materials.