Sol bonded colorant clusters and process for making

摘要

Colorant clusters comprising an aggregation of a plurality of grains of sol-derived material and colorant. The clusters are particularly useful as pigments in liquid compositions, e.g., paints and inks, for forming coatings that are retroreflective immediately upon drying. Also, a process for preparing such colorant clusters comprising admixing colorant in a binder sol to yield a pigment sol and then removing liquid medium from the pigment sol to yield the clusters. Also, a coating composition comprising retroreflective elements, a vehicle, and the aforementioned colorant clusters. After application of the composition to a substrate, the resultant coating is immediately retroreflective upon drying.