The performance of polyurethane adhesives during the lamination process

1. How is the core bonding performance of polyurethane adhesives reflected in the lamination process?

 

Its core bonding performance is mainly reflected in its excellent initial adhesion and final bonding strength. In the early stage of the composite process, polyurethane adhesives usually have good wettability and can fully penetrate the surface of the bonded materials (such as plastic films, metals, fabrics), forming a close contact and providing sufficient initial adhesion to ensure that the materials are initially fixed without shifting. As the curing process progresses, the polar groups in its molecular chain (such as urethane bonds and urea bonds) generate strong van der Waals forces, hydrogen bonds, and even chemical bonds with the surface of the adhered material, ultimately forming a high-strength cohesive structure. This enables the composite material to withstand stresses such as peeling and stretching during subsequent processing and use, and it is not prone to delamination.

 

2. How do the flexibility and toughness of polyurethane adhesives perform after lamination?

 

The adhesive layer formed after the curing of Polyurethane Adhesive has a unique microphase separation structure, which endows it with both excellent flexibility and durability. When using composite flexible packaging materials (such as food bags), this flexibility allows the composite materials to be repeatedly bent and twisted without cracking or delamination. Meanwhile, its performance is stable and can effectively resist the influence of environmental factors. For instance, its low-temperature resistance ensures that it remains bonded even in a freezing environment. Medium resistance (such as oil resistance and grease resistance) ensures that the contents will not erode the adhesive layer. In addition, it also has excellent aging resistance, ensuring the long-term stability of the performance of the composite products during storage and use.

 

3. Process adaptability is a major advantage of polyurethane adhesives. What exactly does this refer to?

 

Process adaptability refers to the ability of polyurethane adhesives to be adjusted and matched according to different composite equipment and product requirements. For instance, it can be formulated into products with different solid contents and viscosities by adjusting the formula to meet the coating requirements of high-speed dry laminating machines or solvent-free laminating machines. The operation window is wide, and parameters such as the pot life, open time, and curing speed can be designed within a certain range, facilitating production control. Whether it is high-temperature dry curing or room-temperature curing, it can find suitable solutions through formula design to ensure efficient, uniform coating and firm lamination effects under different production line conditions, meeting diverse production needs.