Abstract:

In order to improve the dispersity and wettability of organic pigments in water, organic pigment phthalocyanine blue (PB) filter cake, as a representative colorant, was dispersed in the styrene-acrylic monomer and subsequently in its corresponding formed submicron droplets by ultrasonic homogenization. A series of submicron capsules containing pigment particles were successfully prepared by miniemulsion copolymerization, and then used in film forming experiment. It is found that the ultrasonic homogenization can effectively de-aggregated the dry PB filter cakes to realize the uniform and stable dispersion of pigment particles in the styrene-acrylic monomer and its submicron droplets in the form of primary particles. Simultaneously, the content of the pigment can significantly affect the viscosity of monomer dispersion and its miniemulsification potential, and the mass ratio of soft to hard comonomers is the most significant condition to decide the film-forming performance of submicron capsules. When the content of the pigment and the mass ratio of butyl acrylate to styrene are 12 % and 6 : 4, the miniemulsification system and the polymerization process are stable. The prepared microcapsules have good dispersibility and wettability in water and show a clear capsule morphology and a good film-formation performance, which can be directly used in the paint coloring and dyeing.

Key words: organic pigment, submicron capsule, miniemulsion polymerization, latex film