Why is polyurethane adhesive used in food flexible packaging?

Food flexible packaging is usually a composite material, which is made by bonding different materials such as plastic film (such as BOPP, PET), aluminum foil, nylon, etc. through dry lamination process. This structure demands that the adhesive must possess outstanding comprehensive performance, and polyurethane adhesives precisely meet these demanding requirements.

 

First of all, its excellent bonding performance is the cornerstone for its selection. Polyurethane adhesives have extremely strong and extensive adhesion to a variety of polar and non-polar materials, such as plastics, aluminum foil, and paper, and can form a firm composite layer, ensuring that packaging bags will not encounter problems such as delamination and de-bonding during subsequent processing, transportation, and use.

 

Secondly, excellent flexibility and patience are of vital importance. Flexible packaging needs to be frequently squeezed and bent. After curing, polyurethane film has good flexibility and is not prone to brittleness, capable of withstanding these physical deformations. Meanwhile, it has excellent heat resistance (suitable for heat sealing processes), cold resistance (for frozen food packaging), and oil resistance (for oily food packaging), effectively preventing delamination and deterioration caused by the erosion of the contents.

 

Furthermore, its excellent process adaptability makes it highly suitable for mainstream dry lamination processes. Its different types such as solvent-based, solvent-free and water-based can adapt to different production equipment and environmental protection requirements. Especially solvent-free polyurethane adhesives, due to their environmentally friendly, efficient and safe features, have become the development trend of the industry.

 

Finally, extremely high safety and hygiene standards are the bottom line for food packaging. The formula of the regular food-grade Polyurethane Adhesive is pure, with low odor, and its chemical structure is stable. After curing, it will not release harmful substances and migrate into food, meeting the strict food safety regulations of various countries.

 

In conclusion, polyurethane adhesives, with their irreplaceable strong adhesion, durability, process adaptability and safety, have become the most mainstream and ideal bonding solution in the production of composite food flexible packaging.