Paint dewatering refers to the “shrinkage dewatering” of paint slurry, also known as “desizing”, in which a layer of water is precipitated on the surface of paint slurry or on the interface between paint slurry and the wall of material pool.
The main reason is that the suspension system of the coating is not stable. After a period of time, the volume of its own network cementitious structure shrinks, especially when the coating is added with a large amount of sodium bentonite, the phenomenon of dehydration and desizing is more likely to occur.
terms of settlement:
① It is one-sided to strictly control the composition of coating components and use less or no sodium bentonite as suspension agent. Most of the sodium bentonite is composed of sodium carbonate and common bentonite, and the surface is not natural sodium. The effect of attapulgite in the coating is better.
② Increase the ratio of powder to liquid and increase the concentration properly
③ The proportion of excessive density shall be reduced appropriately
④ The particle size of aggregate powder should not be too coarse
⑤ Adding a small amount of appropriate activator to improve the dispersion of aggregate
⑥ The paint with dehydration is prone to “water breaking” (flow ditch) defects when it is applied and hung. When the dehydration is serious, it should be stirred in time and used in the mixing state, or after adding appropriate components to adjust properly, it should be used as soon as possible instead of long time. If the paint is too seriously dehydrated, it is not suitable to use. A certain amount of additives shall be added to adjust it to be qualified before use. If it has deteriorated, it shall be scrapped.