Flexible packaging polyurethane laminating adhesives are key materials in the production of flexible packaging lamination. Due to their excellent flexibility, high bonding strength, and wide adaptability to substrates, they are widely used in packaging fields such as food, medicine, and cosmetics. According to the solvent system, formulation structure, and construction characteristics, the industry mainstream classifies them into three major categories: solvent-based, non-solvent-based, and water-based polyurethane laminating adhesives. The performance and application scenarios of each type of product vary significantly.
Solvent-based polyurethane laminating adhesives are a traditional mainstream category, divided into single-component and two-component types. The two-component type is used by mixing the main agent and the curing agent in a specific ratio, and undergoes a cross-linking reaction to solidify. It has strong adhesion, excellent resistance to high and low temperatures, and outstanding resistance to boiling. It can meet the requirements of high-temperature sterilization, refrigerated storage, etc., for high-end packaging. The single-component type does not require mixing, is simple to operate, and has wide applicability. It is mostly used in ordinary dry-type lamination packaging. This category has mature technology and stable composite effects. It is still the preferred choice for high-end functional flexible packaging to this day.
Solvent-free polyurethane laminating adhesive is the core product of current green production. It does not contain organic solvents, and there is no VOC emission during the construction process, no residue, and it is highly safe. It cures at room temperature, has a fast curing speed, simple production process, and can effectively improve production efficiency and reduce production costs. The product has balanced comprehensive performance and is suitable for most food and daily necessities soft packaging laminating scenarios. It is currently the main alternative product for the environmental upgrade in the packaging industry.
The water-based polyurethane laminating adhesive uses pure water as the dispersion medium. It is non-toxic, odorless, environmentally friendly, and has extremely high safety. There is no risk of being flammable or explosive. Compared with the previous two types of products, it has slightly weaker water resistance and bonding strength, and average weather resistance. It is not suitable for high-temperature, humid, and high-strength usage scenarios. It is mainly used in lightweight, normal-temperature ordinary soft packaging, and is compatible with lightweight and low-demand packaging composite processes.
