Polymer Stabilized Pigment Dispersions for High Reliability Ink-Jet Printing

Abstract

Due to their excellent water and fade resistance properties and their low environmental impact, aqueous pigment dispersions are of growing importance in emerging high throughput aqueous ink jet markets. However, the physical durability (abrasion resistance) of pigment-based inks is often poor. In this paper we describe how dispersing pigments with polymeric dispersants enables significant advantages in abrasion resistance, whilst also delivering stable dispersions across the wide range of ink formulations required to print reliably at high speed, and rapid coagulation on a wide range of substrates. We show that to achieve stability it is essential to irreversibly anchor the dispersant to the pigment surface, and then provide the appropriate balance of electrostatic and steric inter-particle interaction in order to prevent particle aggregation in the ink. We show how these challenges can be met with a new type of pigment dispersion based on Reactive Dispersant technology.