What is the effect of the increase in slurry temperature during the high-speed dispersion process? Is there any way to suppress the temperature rise of the slurry?
During the grinding process of the high-speed disc disperser, the temperature of the pigment paste will inevitably rise . It is also believed that some heat must be generated for a successful dispersing operation, and in fact, if too little heat is generated, the dispersing machine can be considered to be operating inefficiently, or the degree of dispersion is not good . However, the increase in slurry temperature will have some adverse effects: temperature rise, even a small temperature rise, will significantly reduce the viscosity of the material, making the laminar flow trend into a turbulent flow trend, and the kinetic energy of this turbulent flow will immediately turns into heat, causing an undesired temperature rise. Later, the dispersing effect was replaced by the mixing effect. At this time, the dispersing machine can only be regarded as a waste of time and energy to work again. Furthermore, the increase of material temperature will cause damage to additives, evaporation loss or lower efficiency. The solubility of ionic wetting and dispersing agents in water will increase with the increase of temperature, which will reduce the dosage adsorbed on the solid-liquid interface, thereby reducing its use effect.
In addition, the latex paint is prone to swell, particle coarsening and poor construction performance during storage.
It can be said that any measures to suppress the temperature rise during high-speed dispersion are very beneficial . It is a good way to use a jacketed container and pass water through the jacket for cooling . It is also possible to use the method of suspending stirring in the middle, that is, when the temperature rise of the slurry is too high (such as when it exceeds 45C), stop stirring for a period of time, and then perform high-speed stirring operation after the temperature drops, or fully pre-mix under low-speed stirring. Get a good slurry , and then use the shortest time to disperse at a high speed, and the operation will be completed without waiting for an excessive temperature rise to achieve the purpose of dispersion.
