Abstract
As global environmental regulations continue to tighten restrictions on VOC-containing coatings, the need for hydrolytically stable additives in waterborne coatings has never been greater. Alkoxysilanes are a class of widely used additives in the coatings industry, as they act as adhesion promoters between organic coatings and inorganic substrates. Given the high moisture sensitivity of alkoxysilanes, most silane additives rapidly undergo condensation in waterborne coatings, leading to gelling of waterborne coatings within the first few weeks or months on the shelf. This has posed a significant barrier to using silane additives in waterborne coatings. In this new work, we demonstrate the improved properties of waterborne acrylic roof coatings with a novel epoxy-functional oligomeric silane additive that is stable over time. Several properties will be investigated, including stability, adhesion to roofing membranes, ponding water resistance, dirt pick-up resistance, tensile strength, flexibility, and UV weathering resistance. These new findings show significant progress in overcoming the biggest obstacle for the use of silanes in waterborne roof coatings. Coating manufacturers that previously could not use silane adhesion promoters in waterborne systems due to stability issues can now explore this technology with a significantly increased probability of success.
