Introduction to the determination of oil absorption

Since the value of the oil absorption is related to the oil used to knead the pigment, it is recognized that when determining the first oil absorption (see above), it is necessary to use the linseed oil that has been removed and the acid value is not greater than 3.

The degree of grinding of pigments and oils is also a factor that has a significant impact on the value of oil absorption. It has been pointed out before that the pigments (ultramarine blue, chromium oxide, titanium dioxide, etc.) composed of very strong aggregates obtained by general firing can break up the aggregates and reduce the pore volume during grinding, so that The oil absorption is correspondingly reduced. In addition, during grinding, because the air occluded on the surface of the pigment particles is expelled (relevant equipment: Grinder), and because the oil can better wet the surface of the powder particles, the mutual binding force between the particles is reduced as a result. And the distribution is denser, which also caused the reduction of oil absorption.

Therefore, if the oil absorption is measured by any method, such values ​​can be compared.