New Generation of Functional Coating Binder Allows New Coating Properties Design and Higher Coat Efficiency

Abstract

The main functional role of a Paper coating binder is to bind the pigment particles, which make up for more than 85% of the dry weight of the formulation. In addition the binder affects the printability of the paper by helping the absorption and drying of the printing ink. Thus a range of coating binders has been developed over the years to cover the needs of coating pigments with different surface characteristics and fineness as well as work well for various printing processes Approximately 50% of the coating costs can be attributed to the binder system, so one of the main driving forces in binder development has been to reduce the cost of the binder system. As starch as coating binder is significantly cheaper than latex it has become very common to use more and more starch in coating formulations. Especially in pre-coating and also top coating for matte and silk papers of lower quality adding more starch is a feasible option. Too much starch as binder, however, has also some disadvantages like lower binding strength, negative effect on gloss, fold cracking and mottling and results in lower coating solids, high shear viscosity and difficulties to run lower coat weights. The new patented Fennobind binder technology deviates in a significant and surprising way from well-established knowledge about synthetic binders. We will demonstrate in this paper the main deviations and give some ideas how it is possible to utilize these new findings to develop more cost effective formulations and show how papermakers can pass with this knowledge the current boundaries in order to create additional value.