Key effects of humidity on the performance of laser film laminating adhesive and control strategies

1. Mechanism of humidity on the bonding effect of laminating adhesive
Humidity, that is, the content of water vapor in the air, is one of the important factors affecting the rate of chemical reactions and the physical properties of materials. In the process of laser film lamination, the curing of laser film laminate adhesive is a complex physical and chemical process involving multiple stages such as solvent volatilization, polymer chain segment movement and cross-linking reaction. Changes in air humidity directly affect this process, and thus affect the bonding effect.

Optimal humidity range: Experimental data show that when the air humidity is maintained at about 25%, the bonding effect of laminating adhesive is optimal. Under this humidity condition, the solvent volatilization rate in the glue is moderate, and the polymer chain segments can fully move and effectively cross-link to form a strong and tough bonding interface.
Excessive humidity: In humid weather, when the humidity exceeds the appropriate range, the moisture in the air will slow down the volatilization rate of the solvent, resulting in a longer curing time for the glue. This not only reduces production efficiency, but may also cause problems such as insufficient bonding strength and bubble generation due to the long-term incomplete curing of the glue. In addition, high humidity may also promote the growth of microorganisms and affect the long-term stability of the glue.
Humidity is too low: On the contrary, in a dry environment, low humidity will accelerate the evaporation of solvents in the glue, causing the glue to dry too quickly, forming a hard shell on the surface while the inside is not fully cross-linked, resulting in a decrease in bonding strength. In this case, the laminated material is prone to delamination or cracking under stress.
2. Control strategies and practices
Facing the challenges brought by humidity changes, it is crucial to take scientific and reasonable control measures. Here are some effective strategies:

Environmental control: Install a humidity control system in the lamination workshop, such as a dehumidifier or humidifier, to ensure that the humidity of the working environment is stable within the optimal range. This can not only improve the quality of bonding, but also improve production efficiency and product stability.
Process adjustment: Flexibly adjust production parameters based on real-time monitored humidity data. If the humidity is high, the machine speed can be appropriately reduced to give the glue more sufficient curing time; or the drying oven temperature can be increased to accelerate the evaporation of the solvent. When the humidity is low, it is necessary to adjust the glue formula, increase the moisturizing ingredients or use slow-drying glue to slow down the drying speed.
Raw material selection: Choose laminating adhesives that are insensitive to humidity changes or have self-regulating capabilities, such as some specially formulated high-performance glues that can maintain stable bonding performance over a wide humidity range.
Quality inspection and feedback: Establish a strict quality inspection system, regularly test key indicators such as the bonding strength and weather resistance of laminated products, and promptly discover and solve problems caused by humidity changes. At the same time, collect production data, analyze the correlation between humidity and bonding effect, and continuously optimize the control strategy.