Improved Adhesion of Novel Silanes to Difficult Membranes with Silicone Roof Coatings

By Letitia Luu

The mounting pressure to reduce VOC emissions in industrial coating systems has led to increased demand and new developments of high-solids coatings within the cool-roof market. These coatings allow for greater solar reflectance, keeping residential and commercial buildings from overheating. Organofunctional alkoxysilanes are widely used additives in industrial coatings as they form a bridge between organic coatings and inorganic substrates. While most alkoxysilane monomers liberate VOCs in the range of 450–600 g/L, new alkoxysilane oligomers offer even better adhesion properties for coatings while emitting lower VOCs (<350 g/L). This work will demonstrate the significant improvement to adhesion for difficult roofing membranes such as ethylene propylene diene monomer (EPDM), polyvinylidene fluoride (PVDF), and spray polyurethane foam (SPF), and to mechanical properties of high-solids alkoxy-cured silicone roof coatings with the addition of low-VOC silane oligomers. As the market for these coatings continues to grow, alkoxysilane additives will play an important role in achieving better performance and increasing their longevity.