Polyurethane Adhesive and Its Application in the Processing of Food Packaging Composite Films

Polyurethane adhesives are a type of high-molecular material with amino carboxylic acid groups in its molecular chain. Due to their excellent bonding performance, good flexibility, low-temperature resistance, and controllable curing speed, they have become an indispensable key material in the processing of food packaging composite films. 

 

In the production of food packaging composite films, polyurethane adhesives are mainly used for interlayer bonding between multi-layer structural substrates. Common composite structures include plastic films (such as BOPP, PET, PE), aluminum foil, and aluminum-coated films, etc. Through dry-lamination or solvent-free lamination processes, polyurethane adhesives firmly bond these materials of different properties, forming multi-layer composite films that possess barrier properties, mechanical strength, heat sealing performance, and aesthetic appeal. 

 

Among them, solvent-free polyurethane adhesives have received considerable attention in recent years. Compared with traditional solvent-based products, they emit almost no volatile organic compounds, meeting the strict requirements for hygiene, safety and environmental protection in food packaging. Their two-component system achieves rapid curing through the reaction of polyols and isocyanates, which can not only meet the processing needs of high-speed production lines, but also ensure that the composite products maintain stable bonding strength even under extreme conditions such as high-temperature cooking and low-temperature refrigeration. 

 

The requirements for food packaging in terms of safety are particularly prominent. The polyurethane adhesives applied in such scenarios must comply with national food safety standards, ensuring that the migration of harmful substances such as primary aromatic amines in the finished products is below the strict limits. As the industry continues to develop towards greening and functionalization, high-performance, low-migration, and recyclable polyurethane adhesives are becoming the core driving force for upgrading the technology of food soft packaging.