The influence of low-temperature curing process on the performance of flexible packaging polyurethane laminating adhesives
2026,08,12
Curing is a key process for the cross-linking and formation of polyurethane laminating adhesives. Most flexible packaging factories adopt conventional 40℃ to 50℃ constant temperature curing, while the low-temperature curing process, with its advantages of energy saving and prevention of film material deformation, has gradually been applied to thin material and stretchable flexible packaging production. Low-temperature curing refers to the completion of glue cross-linking in an environment of 30℃ to 38℃, and it has special requirements for adhesive formulation and process control.
Under low-temperature conditions, the activity of polyurethane molecules decreases, and the rate of cross-linking reaction slows down significantly. Ordinary general-purpose adhesives are prone to incomplete curing and insufficient cross-linking density, resulting in low composite film peel strength, poor medium resistance, and subsequent continuous stickiness. If the curing time is insufficient, secondary reactions will occur later, causing film surface bulging, shifting, and delamination.
Adhesive with low-temperature curing properties specifically designed for polyurethane can improve the cross-linking activity under low temperatures through modified formulations, completing full cross-linking at lower temperatures. It retains excellent bonding strength and aging resistance while avoiding problems such as film shrinkage, warping, and stretching deformation caused by high-temperature curing, especially suitable for ultra-thin PE films, printed color films, and lightweight composite packaging.
Low-temperature curing production requires appropriate extension of the curing time, strict control of workshop humidity, and avoidance of water vapor interference with the cross-linking reaction. Reasonably matching the specific low-temperature adhesive with curing parameters can not only reduce enterprise energy consumption costs but also effectively improve the appearance and quality stability of fine flexible packaging.
