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: steel grey (also available in black and white)
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






Pietro K. –
Punctual service. Very durable. Great purchase.
Logan –
Very happy with the purchase, works great. Fast shipping, perfect product. Simple to install. Fast and secure delivery.
Sofia –
Been using it for 2 weeks and already see results!
giulio88 –
Great service and product. Well packaged and delivered quickly. Exactly as described. Excellent product.
Luke –
Super value for the money. Works great. Perfectly as described.
olivia_jane –
I was skeptical, but now I’ll order regularly. Looks even nicer in real life.
Michele –
Everything as described.
noemie75 –
Very satisfied, better than I expected. I’ve been using it for 2 weeks and I already see results! Very satisfied, better than expected. Easy to use, without making a mess.
roberto88 –
Fast and secure delivery. Received in perfect condition.
Carter –
Recommended. Exactly as described. Everything as expected. Solid build quality.
maxime88 –
Perfect and functional.
aurelie75 –
A friend recommended it to me and I’m thrilled with the purchase. Easy to use, without making a mess.