Sikaflex 521 UV hybrid adhesive sealant for weather-resistant multi-surface applications
- Weather and aging resistant
- Multi-surface use without treatment
- Sandable and paintable
- Free of isocyanates and solvents
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Sikaflex®-521 UV: high-performance versatile adhesive sealant
The Sikaflex®-521 UV is a single-component silane-terminated polymer (STP) adhesive sealant, designed to deliver exceptional durability and reliability in various applications.
This UV- and weather-resistant product ensures high adhesion on a wide range of materials, including metals, ABS, PC, FRP, and wood, without the need for pre-treatment in most cases.
It is ideal for both interior and exterior sealing, even in demanding environments.
Key features of Sikaflex-521 UV
Weather and aging resistance: Provides exceptional durability, even in extreme weather conditions.
Reliable adhesion: Bonds to various substrates, such as metals, wood, and plastics, without specific pre-treatment.
Eco-friendly formulation: Free from isocyanates and solvents, meeting environmental standards and ensuring safe use.
Paintable and sandable: Enables custom, professional finishes.
Low odor: Facilitates application in sensitive environments.
Good application stability: Non-sagging for increased precision during extrusion.
Technical advantages
Versatility: Designed for flexible bonding and sealing on various materials, including:
Metals and alloys
Wood and composites
Plastics, such as ABS, PC, and FRP
Ceramics and two-component coatings
High chemical resistance: Withstands water, seawater, and diluted weak acids and bases. Temporarily resists fuels, mineral oils, and greases.
Enhanced performance: Offers excellent resistance to tearing, abrasion, and weathering, while maintaining high flexibility and optimal elastic recovery.
Applications and uses of Sikaflex®-521 UV
The Sikaflex®-521 UV is designed to meet the needs of professionals across various sectors:
Automotive industry: Sealing and bonding for exterior and interior components.
Construction: Sealing joints in wood, metal, or plastic structures.
Marine applications: Suitable for saline environments.
RVs and caravans: Durable caulking and protection against leaks.
Usage precautions
Always test on substrates to ensure compatibility and adhesion in real-world conditions.
Do not use on materials prone to stress cracking without prior consultation.
For professional use only.
Technical data
| Property | Value |
|---|---|
| Chemical base | Silane-terminated polymer |
| Available colors | White, gray, black |
| Curing method | Ambient humidity |
| Density (uncured) | 1.4 kg/l |
| Application temperature | 5 to 40 °C |
| Skin formation time | 30 minutes at 23 °C / 50% RH |
| Curing speed | Variable (see technical documentation) |
| Tensile strength | 1.8 MPa |
| Elongation at break | 400% |
| Tear resistance | 5.5 N/mm |
| Service temperature | -50 to 90 °C (temporarily up to 150 °C) |
| Shelf life | 12 months (cartridge/pouch), 9 months (drum) (< 25 °C) |
Adezif in figures
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