U-Seal 550FC | fast curing one-part polyurethane elastic adhesive and sealant, which is PVC-free and odorless

U-Seal 550 FC is a fast-curing, single-component, elastic polyurethane adhesive and sealant designed for industrial assembly, repair, and automotive body construction. Thanks to its thixotropic nature and superior adhesion, the product meets most stringent industrial bonding and sealing requirements. Its special formula ensures it is completely odorless. The adhesive can be easily brushed and shaped to match the original joint, providing an OEM-like finish.

• Single-component polyurethane.
• Application at room temperature.
• Wide adhesion range.
• Non-sagging with excellent thixotropy, clean bead cuts.
• Simultaneously bonds and seals.
• Rapid full-volume curing.
• Paintable, even in a short time, with various water-based and solvent-based paints (pre-testing recommended).
• Easily shaped, brushed, and smoothed.
• Resistant to high dynamic stresses.
• Permanently flexible.
• Vibration and noise damping capabilities.

TECHNICAL DATA

Appearance	Non-sag thixotropic paste
Color	White, Grey, Black. Other on request
Chemical nature	Polyurethane
Curing Mechanism	Moisture-curing
Curing through volume [mm] (NPT Method 07) (24h – 23°C and 50% RH)	ca. 3.2
Hardness Shore A (DIN 53505)	ca. 47
Density [g/cm³ (NPT method 06) (23°C and 50% RH)	ca. 1.38
Skin time [min] (NPT Method 17) (23°C and 50% RH)	ca. 50
Elastic modulus at 100% [N/mm2] (ISO 37 DIN 53504)	ca. 2.0
Tensile strength [N/mm2 (ISO 37 DIN 53504)	ca. 3.0
Elongation at break [%] (ISO 37 DIN 53504)	ca. 480
Application temperature [°C]	From +5 to +40
Temperature Resistance [°C]	From -40 to +100

Datasheet

U-seal 550 FC datasheet 

User Manual

Ensure all surfaces are completely clean, dry, and free from dust, oil, or grease. Surface preparation should follow NPT application guidelines, and if needed, use NPT’s specialized CLEANER or ACTIVATOR products. It is recommended to perform preliminary adhesion tests on the substrate.

Pierce the protective seal at the threaded section. Attach the nozzle and cut at an appropriate angle based on the desired bead thickness and shape. Insert the adhesive cartridge into a manual or pneumatic caulking gun (equipped with a telescopic piston) and apply the adhesive carefully to avoid air entrapment. Once opened, adhesive packages should be used within a short period. The optimal working temperature for both surfaces and adhesive is between 15°C and 25°C.

Shaping and finishing should be completed before the adhesive skins over. U-Seal 550 FC can be painted over, but compatibility should be tested with preliminary paint trials. Be cautious when using alcohol or alkyd resin-based products, as they may interfere with the adhesive curing process and extend paint drying time. It is important to note that the hardness and thickness of the paint layer may reduce the adhesive’s elasticity and cause the paint to crack.

Do not cure the adhesive in the presence of curing silicone sealants. Avoid contact with alcohol and other solvent-based cleaners during curing. When applying the adhesive, ensure no air is trapped. Since this system cures by moisture, adequate exposure to air is essential. Bonded parts may require additional support or retention during the curing process.

Cleaning Instructions

Clean used tools with acetone or a solvent. While the adhesive is still uncured, it can be wiped away with a cloth or paper. Once cured, it can only be removed by mechanical means. To avoid direct skin contact, wear latex, rubber, or polyethylene gloves. If adhesive comes into contact with the skin, wash immediately with soap and water.

Storage Instructions

U-Seal 550 FC can be stored for up to 12 months in its original unopened packaging at temperatures between 10°C and 25°C, in a dry and well-ventilated area. Storage temperatures should not exceed 25°C for extended periods. Keep away from moisture, direct sunlight, and heat sources.