Choosing Low Modulus Polyurethane Sealants for High Movement Joints

High-movement joints are highly susceptible to cracking and leakage due to structural changes and temperature fluctuations, requiring sealants with extremely high performance. Low-modulus polyurethane sealants, due to their ability to maintain stable adhesion under continuous displacement, have become the preferred sealing solution for these types of engineering joints.

What is a Low Modulus Polyurethane Sealant?

Low-modulus polyurethane joint sealants are moisture-curing sealants with excellent elasticity, strong adhesion to various substrates, and weather resistance. They are sprayable and ideal for expansion joints, precast panels, and vertical sealing in bridges and tunnels.

Why Choose Low Modulus Sealants as the Preferred Choice for High Movement Joints?

Unlike high modulus polyurethane sealants, they form a rubbery body after curing, adapting to thermal expansion and contraction. In construction, while high modulus sealants have high tensile strength, they are prone to adhesion failure with the substrate, leading to water leakage in the joints. Low-modulus sealants offer good flexibility, maintaining a stable sealing effect even under joint expansion and contraction.

Advantages of Low Modulus Polyurethane Sealants

1. High movement capability: Can withstand ≥25% joint movement, ensuring a tight seal.
2. Single-component moisture curing: Ready to use, no mixing required, can be applied with a standard caulking gun, and is usually sold in tubes or cartridges for easy use.
3. Good adhesion to various substrates: Provides stable adhesion to concrete, stone, and metal substrates without the need for a primer.
4. Weather resistance: Strong UV resistance and able to withstand high and low temperature changes.
5. Non-sagging: Suitable for vertical joint applications; the sealant will not sag or collapse.
6. Paintable: Paintable after complete curing (compatibility testing of paint and sealant), allowing for easy integration with the surrounding building appearance.

Wide Range of Applications

• Expansion joints / Construction joints: Sealing of joints in precast concrete, masonry, and exterior wall components.
• Floors and pavements: Sealing of cracks in tunnels, basements, balconies, roads, and runways.
• Doors, Windows, and Enclosure Structures: Used for sealing joints between door and window frames and concrete walls, as well as between metal structures.

TP610 Polyurethane caulking sealant​ is currently the preferred choice for building joints. It cures at room temperature, is neutral, non-toxic, and mildew-resistant, possessing excellent durability and resistance to abrasion, tearing, weathering, and water penetration. Construction polyurethane sealant is easy to use and can be applied directly on-site. It is paintable after curing and is non-corrosive to all substrates.

Tengyu Company currently produces two main packaging sizes: 300ml and 600ml, in three main colors: black, white, and gray. Custom packaging and colors are available upon request.

Low-modulus polyurethane sealant has good flexibility and weather resistance and is widely used in building curtain walls (especially expansion joints), roads, and bridges. Tengyu Chemical offers a variety of flexible polyurethane caulk​suitable for various applications.