Coatings clinic

摘要

Flocculation is not a surface defect in itself,but it causes a number of defects and contributes to many others.Floccu-lation is the clumping together of paint components,mainly pigment particles,to form a loose network as shown in Figure 1.We usually think of flocculation as a bad thing,but a certain degree of flocculation can be very useful.It prevents hard settle and helps to give resistance to sagging and cratering.However,too much flocculation definitely is bad.It prevents adequate flow-out and leveling (the surface may be quite rough),often produces streaks and blotches,prevents good color development,causes flooding,floating and Benard cells,and generally hurts appearance.