Weber PU 2A – One-Component Polyurethane Joint Sealant
Weber PU 2A
Weber PU 2A is a low-modulus, one-component polyurethane sealant designed for high-performance sealing and bonding applications. Its flexible structure, excellent adhesion to various substrates, and resistance to challenging weather conditions make it a reliable choice for professional construction projects.
Product Description
Weber PU 2A is a one-component, polyurethane-based, low-modulus joint sealant suitable for both sealing and bonding applications.
Advantages
- Easy to apply
- Excellent adhesion to a wide range of substrates
- Easy tooling and finishing
- High flexibility
- Thixotropic (non-sag) consistency
- Resistant to weathering and water exposure
Areas of Use
Weber PU 2A is suitable for:
- Horizontal and vertical joints requiring elasticity across wide temperature ranges
- Precast concrete element joints
- Prefabricated building element connections
- Roof and terrace expansion joints
- Parapet corner joints
- Wall, floor, window, and door perimeter joints
Suitable Substrates
- Concrete, precast concrete, fiber-reinforced concrete, cement boards
- Wood, metal, and aluminum
- Brick, ceramic, and marble
- Glass and galvanized steel
- Various plastic surfaces
For applications on other substrates, professional consultation is recommended.
Surface Preparation
- Joints must be dry, clean, and free from contaminants.
- Non-porous surfaces such as glass and metal should be free from coatings and may be cleaned with cellulose thinner if necessary.
- Metal surfaces should be treated with an anti-corrosion primer where required.
- Masking tape may be used on sensitive surfaces to achieve neat and precise joint edges.
Application Conditions
- Application temperature: +5°C to +35°C
- Do not apply in excessively hot or highly humid weather conditions.
- Do not apply to frozen surfaces or surfaces at risk of freezing.
Application Instructions
- Apply the sealant so that it contacts both sides of the joint and the polyethylene backing rod.
- Dispense continuously and evenly, ensuring the cartridge or sausage nozzle remains inside the joint.
- Apply in a single layer; avoid overlapping applications.
- Remove trapped air bubbles during application.
- Remove masking tape before the product begins to cure.
- Moisture is required for curing; therefore, application in completely airtight environments should be avoided.
Application Tools
- Caulking gun (cartridge gun)
- Sausage gun
Consumption Table
| Joint Size (mm) | Consumption (ml/m) | Coverage per 600 ml Sausage (m) |
|---|
| 10 × 10 | 100 | 6.0 |
| 15 × 10 | 150 | 3.9 |
| 20 × 10 | 200 | 3.0 |
| 25 × 12 | 300 | 2.0 |
| 30 × 15 | 450 | 1.3 |
Warnings and Recommendations
- Not suitable for environments with high chlorine exposure, such as chlorinated swimming pools.
- Should not be applied simultaneously with silicone-based products in the same area.
- Keep away from solvent-containing materials during curing.
- In cold weather, the product may be conditioned at approximately 20°C before application.
- A polyethylene backing rod should be installed at the bottom of the joint.
- On highly absorbent, glossy, or painted surfaces, the use of Weberprim EP 2K is recommended.
- Joint width should generally be approximately twice the joint depth.
- The cured sealant is paintable; however, paint may crack if significant joint movement occurs.
- White-colored versions may develop slight yellowing over time.
- Air bubbles may form on damp substrates.
- Wear gloves and protective goggles and avoid skin and eye contact.
- Long-term UV exposure may cause some color fading.
Storage and Packaging
- Store in a dry, moisture-free environment between +5°C and +25°C.
- Shelf life: 1 year in original unopened packaging.
Packaging Options
- 280 ml cartridge
- 600 ml sausage pack
Technical Properties
| Property | Value |
| Chemical Base | Polyurethane |
| Curing Mechanism | One-component moisture curing |
| Colors | White, Grey, Roof Red |
| Density | 1.15 ± 0.03 g/cm³ |
| Tensile Strength at Break | ≥ 1.0 MPa |
| Elongation at Break | ≥ 600% |
| Elastic Modulus | ≥ 0.4 MPa |
| Application Temperature | +5°C to +35°C |
| Service Temperature | -30°C to +80°C |
| Shore Hardness | 20 ± 5 Shore A |
| Skin Formation Time (25°C, 50% RH) | 60–90 minutes |
| Curing Rate | Approximately 2 mm/day |
Safety Precautions
- Wear protective gloves, safety goggles, and a mask during application.
- Avoid contact with skin and eyes.
- In case of eye contact, rinse thoroughly with plenty of water and seek medical advice.
- Refer to the Safety Data Sheet (SDS) for disposal and safety information.
Frequently Asked Questions
Where can Weber PU 2A be used?
It is suitable for precast concrete joints, prefabricated construction connections, roof and terrace expansion joints, parapet corners, and window and door perimeter sealing.
Which substrates can it be applied to?
It can be applied to concrete, precast concrete, fiber-reinforced concrete, cement boards, wood, metal, brick, ceramic, marble, glass, galvanized steel, and many plastic surfaces.
Can it be painted?
Yes. However, paint may crack if significant joint movement occurs after application.
What should be considered during curing?
The product should be kept away from alcohol- and solvent-based materials during curing and should not be applied in completely sealed environments.
At what temperatures can it be applied?
The recommended application temperature range is +5°C to +35°C.