Dynamic Surface Tension: A Key Parameter for Excellent Ink Jet Preparations

摘要

The concept of concentrated pigment preparations (pre-dispersions) for inks employed in digital printing, such as ink jet, is increasingly becoming popular in the market. The static surface tension is often given as a quality parameter of these preparations and inks based thereon. However, wetting processes in ink jet, for example, wetting of the printhead interior, drop formation, or interaction with the substrate, generally occur within a very short time (microsecond to millisecond time scale, which is far outside of equilibrium for most cases). Therefore, these ultrafast wetting processes can be understood with the help of the dynamic surface tension rather than by measuring the static surface tension. DSTM (dynamic surface tension measurements) provides a modern tool for a clever selection of appropriate dis-persants with a good dynamic wetting behavior. It also allows the formulation of optimized pigment preparations employing these dispersants, thus enabling the manufacturing of high-quality pigmented inks for high-performance ink jet printing.