1. Raw Material Composition
The flexible packaging polyurethane laminating adhesive is composed of polyols and isocyanates as the core raw materials, forming a two-component system of main agent and curing agent. The main agent mostly uses polyester polyols and polyether polyols, and is adjusted with additives to regulate the wetting property. The curing agent is mainly composed of isocyanate adducts. According to the type of solvent, it can be classified into solvent-based, solvent-free, and water-based types. The solvent-free products do not contain organic solvents, while the water-based ones use pure water as the solvent, which is suitable for environmental protection production requirements. A small amount of leveling agents and antioxidants are added to improve the storage and coating performance.
2. Functional Characteristics
The product is cross-linked and cured into a gel layer through the interaction of hydroxyl groups and isocyanate groups. It has excellent bonding strength, is resistant to both high and low temperatures, and can withstand the erosion of oils, acids, and alkalis. The gel layer is flexible and transparent, does not corrode printing inks, and possesses excellent hydrolysis resistance and heat sealing adaptability. The solvent-free version has low VOC and no residual solvents, complies with food safety standards, is compatible with high-speed laminators, has controllable curing speed, and is less prone to bubble formation, wrinkling, and delamination, and is suitable for laminating films of varying thickness.
3. Application Scenarios
It is widely used in the composite of flexible packaging substrates such as plastic films, aluminum foils, and paper-plastic. In the food industry, it is applied to packaging for snacks, meat products, frozen ingredients, and dairy products. In the cosmetics industry, it is suitable for packaging of laundry detergents and skin care products in flexible tubes. In the pharmaceutical industry, it is used for pharmaceutical composite films and outer packaging of infusion bags. For pesticides and chemical products, its corrosion resistance is utilized to manufacture anti-corrosion composite bags. With the advancement of environmental policies, solvent-free and water-based polyurethane laminating adhesives gradually replace traditional solvent-based products and have become the mainstream bonding material for soft packaging composites.
