PROCESS FOR MAKING SILICA CONTAINING SELF-DISPERSING PIGMENTS

摘要

The disclosure provides a process for making a self-dispersing pigment having an isoelectric point of at least about 8 comprising: (a) providing a silica treatment on an inorganic particle and forming a slurry of silica treated inorganic particles; (b) adding a dual functional compound with an acidic aluminum salt to form an aqueous solution, wherein the dual functional compound comprises: an anchoring group that attaches the dual-functional compound to the pigment surface, and a basic amine group comprising a primary, secondary or tertiary amine; (c) adding a base to the mixture from step (b) whereby the pH is raised to about 4 to about 9 to form a turbid solution; and (d) adding the mixture from step (c) to the slurry of silica treated inorganic particles whereby hydrous alumina and the dual functional compound are deposited on the silica treated inorganic particles to form an outermost treatment. The self-dispersing pigments prepared by this process are useful in making dcor paper that may be used in paper laminates.