A one-component black polyurethane adhesive/sealant that cures on exposure to atmospheric humidity. Sikaflex®-221 bonds well to a range of substrates including metals, metal primers and paint coatings (2-C systems), ceramic materials and plastics. It is also suitable for making permanent elastic seals.

NOTE: The user should seek manufacturer’s advice and perform tests on original substrates before using this product on materials prone to stress cracking. Sikaflex®-221 is suitable for experienced professional users only. Test with actual substrates and conditions must be performed to ensure adhesion and material compatibility.