Description
Sikaflex®-221 is a high-strength 1C polyurethane sealant suitable for a wide range of substrates. It is ideal for elastic sealing and basic bonding applications both indoors and outdoors.
- Pack size: 300 ml cartridge
- Also available in: 400 ml / 600 ml foil pack, 23 l pail, 195 l drum
- Color: white (also available in steel grey and black)
Applications
- Elastic sealing on metals, primers, paints, plastics, ceramics
- Suitable for bodywork, equipment, ventilation, containers, vehicle construction
- Interior joints and basic bonding tasks
Features
- Good adhesion to many substrates without primer
- Can be sanded and painted
- UV- and aging-resistant, low odor, non-corrosive
- Certified to EN 45545-2 R1/R7 HL3 (rail standard)
- Moisture-curing – reacts with atmospheric humidity
- NSF-approved for incidental food contact (Only in certain regions)
- Potable water approved according to AS4020 (Australia)
- Temperature resistant from -50 °C to +90 °C (short-term up to 140 °C)
Technical Data
| Chemical Base | 1C Polyurethane |
| Colors | White, grey, black |
| Curing | Moisture curing |
| Density (depending on color) | approx. 1.3 kg/l |
| Sag Resistance | Good |
| Application Temperature | +5 °C to +40 °C |
| Skin Formation Time (23 °C / 50 % RH) | approx. 60 minutes |
| Volume Change | approx. 5 % |
| Shore A Hardness (ISO 48-4) | 40 |
| Tensile Strength (ISO 527) | 1.8 MPa |
| Elongation at Break (ISO 527) | 500 % |
| Tear Strength (ISO 34) | 7 N/mm |
| Temperature Resistance | -50 °C to +90 °C (short-term to 140 °C) |
| Shelf Life | 12 months (if stored below 25 °C) |
Application Instructions
- Apply using a manual, pneumatic or electric cartridge gun (e.g. 300 ml gun)
- Use suitable nozzles such as the standard nozzle or V-cut nozzle
- Substrates must be clean, dry, and grease-free
- Pre-treatment recommended using Sika® Primer-207 (for glass/metal)
- Smooth before skin formation using Sika® Tooling Agent N
- Remove uncured material with Sika® Remover-208, cured product must be removed mechanically
Paintability
- Paintable after skin formation
- For best results: fully cure before painting
- Compatibility with 1C-PUR and 2C acrylic paints should be tested
Chemical Resistance
- Resistant to fresh and seawater, diluted acids and alkalis
- Short-term resistant to fuels, oils and greases
- Not resistant to concentrated acids/alkalis or organic solvents
Sikaflex 221, PU sealant, 1C adhesive, polyurethane, elastic joint, paintable, EN45545, cartridge accessories
Hazard Statements (CLP)

Signal word: Danger.
Hazard Statements (H-Sentences)
- H334: May cause allergy, asthma-like symptoms or breathing difficulties if inhaled.
- H373: May cause damage to organs (central nervous system) through prolonged or repeated exposure by inhalation.
Precautionary Statements (P-Sentences)
Prevention:
- P260: Do not breathe mist or vapour.
- P284: Wear respiratory protection if ventilation is insufficient.
Response:
- P304 + P340: IF INHALED: Move person to fresh air and keep comfortable for breathing.
- P342 + P311: If experiencing respiratory symptoms: Call a POISON CENTER/doctor.
Disposal:
- P501: Dispose of contents/container in accordance with local regulations.
Sika Deutschland GmbH, Kornwestheimer Str. 103-107, 70439 Stuttgart, GERMANY, +49 711 8009-0, [email protected], www.sika.com






Alessandro –
Fast shipping and good quality. Perfectly as described. Better than I thought; I’m satisfied.
Cecilia –
Very effective; I noticed a change in just one week. Solved my problem completely! Packaging was slightly damaged, but product is excellent.
Fiona –
Excellent product, worth every cent.
Elena F. –
Surprisingly good quality for the price. I noticed the difference right away!
Emilia L. –
Packaging slightly damaged, but the product is excellent. Very effective, I noticed a change in just a week. The quality pleasantly surprised me.
Julie R. –
I’ve been using it for 2 weeks and I already see results! Not too big, not too small, perfect.
Nicole J. –
Been using it for 2 weeks and already see results! I noticed a difference after a short time! The quality surprised me in a good way. Easy to use, without making a mess.
Abigail P. –
Super fast delivery, thank you. Better than anything I’ve tried so far. A friend recommended it and I’m so glad I ordered. Perfect for my needs; I couldn’t be happier.
ellie.love –
Packaging slightly damaged, but the product is excellent.
Oliver –
Delivery faster than expected. Excellent product. Great customer support.
daniele_it –
Very satisfied with the purchase. No reason to complain. Exactly as described. Met my expectations.
Bianca –
I was skeptical, but now I order regularly. The quality surprised me in a good way.
caroline.x –
Been using it for 2 weeks and already see results! A friend recommended it; I’m very happy with the purchase. Very satisfied, it’s even better than I expected.
Sebastian –
Arrived as promised. Super value for the money. Arrived on time and in excellent condition.
tyler_xo –
Clear recommendation. Great value for money.