Preparation of polymer-encapsulated pigment for formulations of inkjet inks

Abstract

In textile inkjet printing, pigment inks have become one of the main colorants because of its excellent light fastness and suitable to all sorts of fibers. Pigments are applied as aqueous dispersion due to their water insoluble. Encapsulation of pigments with polymer can protect them from agglomeration and unwanted environmental influences such as UV radiation or acid and alkali. The encapsulation leads to better storage stability, color stability and durability, and the film formation can be adjusted. In this paper, organic pigments (P.B.65, 73, 14, and 83) were encapsulated with polystyrene and polyacrylates via miniemulsion polymerization. The properties of pigment dispersions dispersed in water and monomers were evaluated. With ultrasonication time prolong, the particle size of pigment dispersions decreased. For 30 min ultrasonication, the particle size of P.Y. 14 and 83 dispersions in water was smaller than that of P.Y. 65 and 73. The particle size of pigment dispersion in styrene was smaller than that in acrylates. The stability of P.Y.83/monomer dispersion was the best. There was almost no separated monomer layer in P.Y.83 dispersions, but significant separated monomer layer can be seen in P.Y.65 dispersions. The encapsulation ratios and efficiency of P.Y.83 with polymers were larger than that of P.Y.65. Acrylates tend to adsorb better on the surface of pigment particles than methacrylates, while the encapsulation ratios of polyacrylates were higher.