As an efficient adhesive material, hot melt adhesive film from Alster has been widely used in many industries, especially in large-area lamination applications, such as the lamination of fabrics, coils and sheets. With the continuous expansion of the application of hot melt adhesive film, the requirements for the lamination process have become more stringent. In the lamination process, temperature, time and pressure are three key factors. Reasonable control of the parameters of these three is the key to ensure the quality of hot melt adhesive film lamination.
1. Control of lamination temperature
Lamination temperature refers to heating the hot melt adhesive film to a certain temperature so that it reaches a melting state, so that it can react with the surface of the substrate to form a bonding reaction. In the hot melt adhesive film lamination process, temperature control is crucial, and too low or too high temperature may lead to unsatisfactory lamination effects.
First, too low a temperature will cause the hot melt adhesive film to fail to melt completely. The hot melt adhesive film can only exert good fluidity and permeability when it reaches its melting point. If the temperature is not high enough, the fluidity of the adhesive film is insufficient, and it cannot penetrate into the surface of the substrate, resulting in weak adhesion and poor lamination effect. On the contrary, if the temperature is too high, although the film can melt quickly, the excessive temperature may cause the film to penetrate the surface of the substrate, resulting in glue penetration, affecting the appearance quality, and even causing the bonding layer to be weak and uneven.
It is worth noting that the temperature displayed on many composite equipment is the temperature inside the machine, not the surface temperature actually in contact with the film. Therefore, it is recommended to use a temperature gun to monitor the temperature of the composite surface in real time during operation to ensure that the temperature is controlled within the ideal range to achieve the best composite effect.
2. Mastering the composite time
The composite time refers to the heating time and cooling time required when the hot melt adhesive film contacts the substrate. In the composite process, time control is also crucial, and too short or too long time will affect the composite quality.
First, the hot melt adhesive film needs a certain heating time to fully melt. When the film melts, it will have a certain fluidity and can penetrate into the surface of the substrate. If the heating time is too short, the hot melt adhesive film is not completely melted, and it cannot form an effective bond with the surface of the substrate, resulting in insufficient bonding. If the heating time is too long, although the film is completely melted, glue penetration may occur, affecting the appearance and weakening the bonding.
After the lamination is completed, sufficient cooling time is required. Only when the adhesive film cools to a certain temperature can the adhesive layer be effectively formed. If the cooling time is insufficient, the adhesive film may not be completely cured, resulting in weak bonding, and even problems such as the adhesive layer falling off. Therefore, during the entire lamination process, the reasonable control of heating time and cooling time is a necessary condition to ensure that the hot melt adhesive film forms a firm and stable bond with the substrate.
3. The role of lamination pressure
Lamination pressure refers to the pressure applied between the hot melt adhesive film and the substrate during the lamination process. Although many people may ignore this, pressure actually plays a vital role in the hot melt adhesive film lamination process.
Too little pressure may cause the hot melt adhesive film to be unable to effectively contact the substrate, affecting the penetration and bonding effect of the adhesive film. Excessive pressure will cause the hot melt adhesive film to be squeezed out of the surface of the substrate, making it impossible to form a uniform bonding layer, and even affecting the appearance and function of the composite product.
In addition, some materials (such as metal, wood, etc.) may have thermal stress themselves and will deform during the cooling process. Therefore, in addition to the need to control a certain pressure during the lamination process, for these materials, the lamination process also needs to add a cold pressing step. Applying appropriate pressure before cooling can avoid poor lamination due to material deformation and ensure the stability of the lamination effect.
Conclusion
In summary, the lamination process of hot melt adhesive film requires strict temperature, time and pressure control. Too high or too low temperature may cause the hot melt adhesive film to fail to melt completely or cause glue penetration, affecting the lamination quality. The heating and cooling time needs to be reasonably controlled to ensure that the adhesive film can be fully melted and effectively cooled to form a strong bond. The lamination pressure directly affects the contact degree between the adhesive film and the substrate.
Too little or too much pressure is not conducive to the lamination effect. Therefore, these three elements in the lamination process must be precisely controlled. Only in this way can the hot melt adhesive film show excellent bonding performance in large-area lamination applications.
