How it works:
A high-speed disperser is a device that applies strong shear and impact forces to the material through a high-speed rotating dispersion disc, thereby achieving uniform dispersion of solid particles in the liquid medium. Its core function is to break the agglomeration between particles, promote wetting, and form a stable suspension system. In the dispersion process, the linear velocity of the edge of the dispersion disc is a key parameter, and its calculation formula is:
v = π × d × n
Among them, v represents the edge linear speed of the dispersion disc (m/s), d represents the diameter of the dispersion disc (m), and n represents the spindle speed (rpm). Higher linear velocities typically result in stronger shear forces, which can help improve dispersion efficiency.
Process requirements for the preparation of water-based inks
Water-based inks are mainly composed of water-based resins, pigments, additives and water. The preparation process requires the pigment particles to be fully wetted and stably dispersed in the water-based connector to achieve excellent coloring, gloss, and printability. Key points of the process include: pre-mixing and wetting of pigments; Efficient dispersion to reduce pigment particle size and prevent reagglomeration; and stability control of the entire system. These links put forward clear requirements for the shear efficiency and mixing uniformity of the dispersion equipment.
Specific applications:
In the production of water-based inks, the high-speed disperser mainly undertakes the preparation of pigment paste. First, pigments, partial water-based resins, wetting dispersants and water are preliminarily mixed to form a premixed slurry. Subsequently, in the high-speed disperser, the dispersion disc breaks up the agglomerated pigment particles under high-speed rotation and achieves the desired fineness through strong hydraulic shear and micro-turbulence. This process effectively exposes the fresh surface of the pigment, promotes the coating of resin and additives, and forms steric resistance or electrostatic stabilization, thereby ensuring the stability of the ink during storage and use.
Process parameters
The dispersion effect is directly affected by the equipment parameters and process conditions. The main control parameters include the shape and diameter of the dispersion disc, the spindle speed, the dispersion time, the viscosity of the material, and the feeding sequence. For example, moderate viscosity is good for transferring shear forces, while too high viscosity can lead to heat buildup. During the production process, the process needs to be optimized by stepping up speed and controlling the temperature. The following is a brief description of the key parameter relationships:
| Parameter Name | Implications and considerations |
| Dispersion coil line speed | It affects the shear force and needs to be adjusted according to the hardness of the pigment and the target fineness. |
| Spread time | Associated with dispersion efficiency, too long can lead to overheating or excessive shear. |
| material temperature | It is necessary to monitor to prevent changes in the properties of the resin or water volatilization caused by excessive temperature. |
| Solid content and viscosity | It affects the shear force transmission efficiency and needs to be kept within the appropriate range. |
Advantages and limitations
High-speed dispersers show multifaceted applicability in the preparation of water-based inks. Its structure is relatively simple, easy to clean, and suitable for rapid color change production of water-based systems. At the same time, it can efficiently complete the dispersion of most medium and low viscosity pigment slurries, and the investment and operating costs are economical. However, for some systems that require very high fineness or contain extremely hard pigments, it may be difficult to meet the requirements by relying solely on high-speed dispersion, and subsequent grinding with a sander is often required. In addition, for very high viscosity slurries, their mixing and heat transfer efficiency is limited.
Summary
High-speed dispersers are key equipment for water-based ink preparation, especially in the pre-processing stage of pigment dispersion. By understanding its working principle and systematically controlling the process parameters, the wetting, dispersion and preliminary stabilization of pigments can be efficiently realized, laying the foundation for obtaining water-based ink products with stable performance. In actual production, it is often used as the core equipment in the front section of the decentralized process, and cooperates with other process equipment to build a complete and efficient production line.