2507 Capillary tube function explanation
Due to the complex microstructure of the undried water-based pigment filter cake, when the pigment particles are surrounded by the oil phase, the contact angle is less than 90°, and infiltration can occur. At this time, the pore size of the 2507 Capillary tube inside the particle is related to the pressure difference of the 2507 Capillary tube. The finer the 2507 Capillary tube, the greater the wetting force of the solvent. However, because the 2507 Capillary tube is not uniform and has poor regularity, the penetration rate of the particles in different regions of the oil phase is different, so that the water is surrounded by the oil before it is completely replaced by the oil, resulting in a small amount of water that cannot be completely replaced. remains inside the particle.
However, the general trend of the 2507 Capillary tube is to help the transfer of pigment molecules to the oil phase. As long as the pigment particles have a certain lipophilicity, the oil phase will spontaneously wet the surface of the aggregated particles under the action of stirring, and make it in the oil phase. The oil phase gradually disintegrates, and finally the oil enters the interior of the pigment particles and the water is expelled. A small amount of moisture remaining inside the particles can also be separated by heating under vacuum.