1994 Volume 67 Issue 9 Pages 547-554
Acid and base amounts of pigments were estimated by a back titration method using bases and acids of various strength. The dispersibility in an acidic, a neutral and a basic acrylic resins was correlated to the acid and base amounts of the pigments.
The acid amounts of all four titanium dioxide pigments (TiO2-A, -B, -C, and -D) were almost proportional to the base strength of the added base. For two pigments (TiO2-C and -D), the base amounts, measured using weak acid, were small. On the other hand, the base amounts of the other pigments (TiO2-A and -B) were almost constant, even though the acids of different strength were used.
For titanium dioxide pigment, iron oxide, and copper phthalocyanine blue pigments, the gloss of their dispersed pastes in the neutral, the acidic and the basic resins, which is an indicator of dispersibility, was measured. The difference between the gloss value for the acidic and the neutral resins showed good correlation with the base amount of the pigments measured using acid having almost the same strength as the acid of resin. The same result was obtained for the basic and neutral resins, for the acid amount of the pigments.
