In general
carbon black has large surface area
high oil absorption and low surface energy;
it tends
to be repellent
to the vehicle and lose stability,
such as significant increase in viscosity or reaggregation in the vehicle. In this case, the leveling,
gloss, image sharpness and other properties of the film surface will be affected and high-quality appearance cannot be expected.
We examined the effects of one of our polymer dispersants using an alkyd melamine paint, which includes highly acid carbon black as we mentioned at the beginning (Figure-4)
We used Disparlon DA-703-50 (the amount added was 60% of the pigment weight) as the dispersant and a batch-type test sand mill as the dispersing machine.
When the additive was not used,
the viscosity of the mill base (measured by the E-type viscometer/25℃) declined sharply in the early stage of dispersion and then declined mildly.
When DA-703-50 was added, the viscosity was low from an early stage and the gloss