U-Seal 907 | One-part polyurethane low modulus construction sealant

U-Seal 907 is a one-component polyurethane sealant specifically designed for construction applications. It is easy to apply and non-sagging. U-Seal 907 cures upon exposure to moisture in the air, forming a high-performance compound with permanent elasticity and excellent resistance to aging and weathering over time.

• Simultaneously bonds and seals.
• Permanent elasticity; accommodates joint movement up to ±50%.
• Easy to apply with excellent consistency.
• Good thixotropy, non-sagging.
• Outstanding adhesion to all common building and industrial materials without the need for primer.
• Leaves no staining on concrete or porous materials.
• Highly resistant to aging, weathering, detergents, seawater, and limewater.
• Can be painted over with many water-based and solvent-based paints (preliminary testing is recommended).

Applications

U-Seal 907 is a versatile, high-performance construction sealant for expansion and construction joints in vertical and horizontal applications, including joints in prefabricated elements, exterior wall joints, and cladding joints.

U-Seal 907 is suitable for sealing metal roofs and gutters, bridge and balcony railings, waterproofing joints between tiles, blocks, wood, concrete, metal, window or door frames, joints in water channels, and for general hydraulic sealing applications exposed to water.

Certificates

Technical Data

Instructions for Use

The surface to be treated must be completely clean, dry, and free of dust or grease. U-Seal 907 exhibits excellent adhesion without the need for a primer on most common construction materials. Therefore, the use of a primer is unnecessary if the surface is properly prepared and reinforced. However, tiles, natural stone, plastics, paints, coatings, and other surface treatments often present adhesion challenges. Due to the variability and unpredictability of these materials, preliminary testing is recommended. Prefabricated panels using release agents other than polyethylene film should be cleaned by sandblasting or mechanical abrasion, ensuring no dust remains.

Recommended application temperature: 15°-25°C. For easier application in cold weather, we recommend storing the material at approximately 25°C before use. To ensure free movement of the sealant within the joint, it is essential that the sealant does not adhere to the bottom of the joint. Therefore, to create a proper joint, an airtight polyethylene backer rod should be placed at the correct depth.

If necessary, apply a suitable primer to the joint sides, and allow sufficient drying time to avoid solvent entrapment, which, under rising temperatures, could cause air bubbles in the uncured sealant. For optimal performance, the sealant should be injected into the joint when the gap is at its midpoint between expansion and contraction as designed. Ensuring firm application of the sealant into the joint guarantees complete contact with the joint sides and the backer rod at the bottom. Keep the nozzle in the sealant and maintain a steady flow to avoid air entrapment. Avoid overlapping the sealant to eliminate the risk of air pockets.

Finishing and smoothing should be completed during the sealant’s tack-free time. U-Seal 907 can be overpainted. The paint should be tested for compatibility by conducting preliminary tests. Care should be taken when using alcohol-based or alkyd resins as they may affect the sealant’s curing process and extend the paint’s drying time. The hardness and thickness of the paint film may impair the sealant’s elasticity, potentially leading to paint film cracking.

Do not allow the sealant to cure in the presence of curing silicones. Avoid contact with solvent-based cleaners during the curing process. When applying the sealant, ensure no air entrapment. Since this is a moisture-curing system, adequate exposure to air is essential.

Cleaning Instructions

Clean tools with acetone or solvent. Uncured sealant can be removed with paper or cloth. Once cured, the product can only be removed mechanically. Avoid skin contact by using latex, rubber, or polyethylene gloves. If skin contact occurs, remove immediately and wash thoroughly with soap and water.

Storage Instructions

U-Seal 907 can be stored for 12 months in its original (unopened) packaging at temperatures between 10°C and 25°C in a dry, cool place. Storage temperatures should not exceed 25°C for prolonged periods. Avoid storing in humid areas, direct sunlight, and near heat sources.