Description
Product Data Sheet
Sikaflex®-221 is a high-performance, one-component polyurethane adhesive sealant engineered for flexible sealing and bonding in industrial, transportation, marine, and construction environments. This moisture-curing elastomeric sealant forms durable, permanently elastic bonds that resist vibration, weather exposure, thermal expansion, and demanding service conditions.
Designed as a versatile general-purpose adhesive sealant, Sikaflex®-221 bonds effectively to metals, metal primers, painted surfaces, ceramics, plastics, fiberglass reinforced plastic (FRP), wood, and many common industrial substrates. Its broad adhesion profile and flexible polyurethane formulation make it ideal for both sealing and light bonding applications involving similar or dissimilar materials.
The sealant features a non-sag consistency for clean vertical and horizontal application using manual, pneumatic, electric, or automated dispensing equipment. Once cured, Sikaflex®-221 forms a durable elastomer that can be sanded and painted, helping improve aesthetics and finishing flexibility in fabrication and assembly operations.
Sikaflex®-221 offers excellent resistance to aging, fresh water, seawater, diluted acids, and diluted caustic solutions while maintaining flexibility over a wide operating temperature range. Its low-odor, non-corrosive formulation supports comfortable application and long-term substrate compatibility in demanding industrial environments.
The product provides approximately 45 minutes of open time and develops a skin in about 60 minutes under standard conditions, allowing sufficient working time for positioning and tooling during assembly. Its moisture-curing chemistry delivers long-term elasticity and durable sealing performance after cure.
Common applications include:
- Industrial joint sealing and bonding
- Transportation and trailer assembly
- Interior and exterior lap seam sealing
- Marine and RV fabrication
- HVAC and metal building assembly
- General construction sealing applications
- Bonding and sealing dissimilar materials
- Equipment fabrication and maintenance
