Vehicle Sealant Resin Featuring Eco-Friendly Formulation and Reliable Adhesion HF D35 is a medium modulus silyl modified polymer developed for industrial bonding and sealing applications that require a balance of adhesion strength, flexibility, and long-term durability. Manufactured by Risun, this moisture-curing polymer is designed to help adhesive and sealant manufacturers formulate products suitable for equipment assembly, industrial fabrication, transportation systems,