Analysis Of The Effect Of Moisture On Organic Pigments

Organic pigment particles have a high energy content on their surface, and their surface always adsorbs a certain amount of material, with water being one of them. The water referred to here refers to wet storage water, which is the water adsorbed on the surface of the pigment, excluding the water bound in the chemical components of the pigment. It is impossible for the pigment surface to be absolutely free of water. Even if the dried pigment is baked, it will still absorb water once exposed to the air until it is in phase equilibrium with the ambient temperature and humidity.
An appropriate moisture content in organic pigments is necessary, as the presence of moisture can affect the grinding and dispersion of pigments in coatings, which is particularly prominent in Chinese pigments. If the moisture content of the pigment is too low, it is difficult to grind, and if the moisture content is too high, it will cause anti coarsening.
Generally, moisture is a flocculant for paint making, and appropriate moisture will not cause excessive flocculation. The presence of moisture can affect a range of properties of pigments, such as color brightness and oil absorption. Therefore, based on the usage of different organic pigments, the reasonable moisture content of different pigments is specified. Generally, the moisture content of pigments does not exceed 1%, while for Hualan, it is 4%. Carbon black can specify a moisture content of up to 10%.