High performance kaolins for lithographic inks

 
Kaolin or china clay has been traditionally used as an extender in lithographic printing ink formulations. We will report here on the latest kaolin developments to achieve technical benefits and optimise the cost-performance of offset ink formulations. We have studied how particle size, shape and chemistry affect print performance including print gloss and density. The analysis of ink surface roughness has allowed us to define suitable kaolin parameters to achieve high gloss in heatset inks. We have designed laboratory tests to investigate the stability of ink-fount solution emulsions in offset inks and will report on engineered kaolin grades able to give good water uptake whilst minimising kaolin washout, hence resulting in optimised printability and runnability on the printing press.