Lorama Inc., Polysaccharide Resin

Dispersants increase the stability of the pigments suspended in the alkyd resin. True polymeric dispersants prevent pigment flocculation. Dispersants must be added before the pigment is added in order to maximize absorption of the dispersant onto the pigment.
The particle size of TiO2 is small when compared to the thickness of an enamel film in which it is used. TiO2 has a theoretical optimum particle size between 0.2 and 0.3 microns, but as shipped, is considerably larger because of the formation of agglomerates during the manufacturing process and extended storage. The energy of simply stirring TiO2 into alkyd resin is not great enough to overcome the particle attractive forces preventing the breakup of the agglomerates. If the number of these agglomerates is not limited, the end-use properties of the enamel are adversely affected (gloss, hiding power, tint strength, poor suspension, color streaking in tints, and grit in the film). Although the TiO2 is designed to yield optimum hiding power, gloss, and color, these basic properties may not be realized if the initial dispersion of TiO2 is inadequate. The optimum dispersion for the TiO2 is when further grinding will not change the particle size distribution.