Sikaflex-221 is a one‑component polyurethane adhesive sealant with details on composition, properties, application, safety, and storage.
Sikaflex-221 is a multi‑purpose, non‑sag, 1‑component polyurethane sealant that cures on exposure to atmospheric humidity, forming a durable elastomer. It is available in several colors and meets various industry standards such as ASTM C920 and NSF‑ANSI 61.
The data sheet provides technical specifications, recommended application temperatures (41 °F – 104 °F), tack‑free and open times, safety precautions, packaging options, and warranty information. Users are advised to follow the handling, storage, and personal‑protective‑equipment guidelines to ensure safe and effective use.
| Chemical base | 1‑C polyurethane |
|---|---|
| Color options | White, black, aluminum gray, colonial white |
| Density (uncured) | 10.6 lb/gal |
| VOC (EPA method 24) | 0.4 lb/gal (48.3 g/l) |
| Application temperature range | 41 °F – 104 °F (5 °C – 40 °C) |
| Tack free time | 60 min |
| Open time | 45 min |
| Shrinkage | 5 % |
| Shore A hardness (ASTM D2240) | 40 |
| Tensile strength (ASTM D412) | 260 psi |
| Elongation at break (ASTM D412) | 500 % |
| Glass transition temperature | -49 °F (-45 °C) |
| Service temperature range | -40 °F – 284 °F |
| Shelf life (stored <77 °F) | 12 months |
Apply Sikaflex‑221 between 41 °F and 104 °F (5 °C – 40 °C).
The tack‑free time is about 60 minutes.
Wear chemical‑resistant goggles, gloves, and protective clothing, and use a properly fitted respirator in poorly ventilated areas.
Uncured product should be used within a relatively short time after opening; the shelf life is 12 months when stored below 77 °F (25 °C).