Product description
Flexible sealing and simple bonding across different materials
Sikaflex-221 is a professional, moisture-curing polyurethane adhesive sealant for applications that need a lasting elastic seal. It bonds well to a range of substrates, including metals, metal primers, compatible paint coatings, ceramics and plastics. Sika describes it as particularly suited to internal sealing and simple bonding applications.
Key benefits
- Bonds to a wide range of suitable materials
- Cures to a permanent elastic seal
- Good resistance to ageing
- Non-corrosive and low odour
- Can be sanded and painted, subject to a compatibility test
- Non-sagging for controlled application
Before you apply: Surfaces must be clean, dry and free from grease, oil and dust. Apply between +5°C and +40°C; Sika states that +15°C to +25°C is the optimum range for the substrate and sealant. Test adhesion and material compatibility on the actual surfaces, especially plastics prone to stress cracking. Tool and finish the bead before it skins.
Painting: Sika says Sikaflex-221 can be painted after a skin forms, but paints must be tested for compatibility. A rigid paint may crack over a moving sealant joint.