Some customers may have problems such as poor laminating effect when using thermal lamination film. According to the process practice, the quality of composite film laminating is mainly affected by 3 factors: temperature, pressure and speed. Therefore, correctly managing the relationship between these 3 factors is crucial for ensuring the quality of pre-coating film laminating and its impact on downstream production.
Temperature:
It’s the first key factor. The adhesive used for the heat laminating film is hot melt adhesive. The temperature determines the melting state of the hot melt adhesive, its leveling performance, the diffusion ability between the hot melt adhesive molecules and the film, the ink layer, the paper substrate, and the crystallinity of the hot melt adhesive. Only by correctly controlling the temperature in the working area can the solid hot melt adhesive layer on the film be completely melted into a flowable state, with proper fluidity, to achieve wetting and adhesion to the surface of the printed matter. At the same time, it is guaranteed to be cured immediately after lamination, so that the laminated product is smooth and shiny, the adhesive layer is well fused, no creases, and the ink can be peeled off.
Pressure:
While properly controlling the lamination temperature, appropriate pressure should also be applied. This is because the surface of the paper itself is not very flat. Only under pressure can the flowable hot melt adhesive fully wet the surface of the print by expelling air. This allows the colloidal molecules to diffuse and interlock with the ink layer and paper fibers, achieving good adhesion and complete coverage of the entire surface of the printed product. The result is a glossy appearance, no fogging, a smooth bondline, no creases, and good adhesion. By appropriately increasing the pressure under non-folding conditions, the thermoplastic curing ability of the hot melt adhesive can be fully utilized to ensure that the laminated product has strong resistance to various physical peeling and impact forces (such as indentation and bronzing) during the bonding process ability. follow-up process. This guarantees perfect consistency in the internal structure and surface condition of laminated prints.
Speed:
Paper laminating is a compound movement in dynamic progress. The speed of movement determines the residence time of the paper-plastic composite material on the working interface during the thermocompression bonding process. It also determines the input value of temperature and pressure in the actual production process of paper-plastic composite materials and the actual effect achieved. When the lamination temperature and pressure are constant, the speed change will affect the lamination effect. Due to the upper temperature limit and pressure limitation, the effect will only change in the direction of less than the set value. As the speed increases, the effect will decrease significantly, the heat pressure will weaken, and if the running speed is too fast, it will cause the adhesion force to become weak, resulting in atomization. If it’s too slow, it’s inefficient and may even cause bubbling. Therefore, the running speed of the pre-coating laminating film determines the bonding time of the thermal laminating film and the paper print.
The actual values of temperature, pressure, and speed all have a certain range. Finding the best value in practice is very important to ensure the lamination effect of the hot lamination film and create favorable conditions for subsequent processes such as binding covers and spines.
Post time: Aug-01-2023