The Waterborne Symposium

Abstract
Microfibrillated Cellulose – The Effect of a Novel and Renewable Multifunctional Additive on Common Waterborne Coating Issues
Co-author: Ali Moosavifar

There is a growing interest to move towards waterborne systems in the coatings industry due to environmental and occupational health reasons. However, the change is not always straightforward and often new technologies are required to obtain the same performance as with solvent borne systems.
Microfibrillated cellulose (MFC), a value-added and multifunctional product made of cellulose, consisting of fibers with lateral dimensions in the nanoscale and lengths up to micron scale. The main characteristics of this unique fiber structure is its resembling of both water soluble polymers and insoluble additives, leading to a versatile and efficient alternative to technologies currently available. The high inertness, compatibility and stability of MFC is opening up new possibilities for waterborne paints and coatings, especially for the more demanding formulations. MFC secures high viscosity at rest, giving good stability, as well as offering shear thinning behavior and rapid viscosity build-up, which prevents sag during application. The aim of this work was to evaluate the effect of MFC to the rheological behavior of the coating formulation as well
as to the final film properties. Waterborne exterior flat paint, based on a blend of acrylic and vinyl acrylic binderswas used to investigate the effect of MFC on prevention of syneresis as well mud cracking of the  coating. Deep base acrylic paint was used to evaluate the effectiveness of MFC to prevent viscosity loss on tinting, color float and sagging. We will demonstrate how MFC can solve typical challenges in waterborne high quality architectural paints and coatings regarding, for example, mud-cracking, viscosity loss, sagging and sprayability. This study will widen the understanding of the opportunities of MFC on coatings but as well as to demonstrate its potential on other fields such as adhesives and in demanding formulations. Understanding the effect of these novel hybrid type of multifunctional additives on the formulation as well as on the film properties, is essential.