Hot melt adhesive films have been used in many industries, such as the shoe industry and the clothing industry. In fact, different industries have different requirements for hot-melt adhesive films, and the specific processes are also different. How to obtain a firm bonding effect by hot-melt adhesive film compounding is a problem that many users are concerned about.
Although the industry is different, the bonding principle of hot melt adhesive film is indeed the same. To get a good bonding effect, you should pay attention to the following aspects:
The hot melt adhesive film needs to be heated and melted to have adhesive properties; otherwise, it is almost indistinguishable from an ordinary plastic film. Therefore, the temperature is the primary condition for the good bonding of hot melt adhesive films.
Different materials of hot melt adhesive film, its melting temperature is different, that is, there are high and low-temperature points. If the heating temperature is higher than the temperature required by the hot melt adhesive film, the hot melt adhesive film will melt too fast and melt too much so that the glue can easily penetrate into the material to adhere. Especially in some textile fields, if the temperature is too high, some glue penetration is often encountered, which affects the bonding effect.
If the bonding temperature is too low to reach the recommended operating temperature of the hot-melt adhesive film, the hot-melt adhesive film will not melt completely or melt too slowly so that the glue cannot melt within a certain period of time. If it spreads well into the adherend, it cannot form a good bond.
When we bond materials, we put the hot melt adhesive film between the materials to be bonded, and at the same time, we need to apply a certain amount of pressure to finally get a good bond. The pressure is applied so that the melted glue can spread on the surface of the adherend as soon as possible because the glue cannot continue to spread after the hot melt adhesive film is cooled.
At the same time, applying a certain pressure can make the glue liquid form a uniform glue layer on the surface of the adherend. Some adherents have stress themselves, and cold pressing is required after hot pressing, which can effectively avoid bonding failure caused by stress release.
Temperature and pressure are two essential elements for the good bonding of hot melt adhesive films, and another important element is the hot pressing time. Because it takes time to heat the hot-melt adhesive film, it also takes time for the hot-melt adhesive film to spread on the surface of the adherend after melting. If the hot pressing time is too long, the adhesive will penetrate excessively. If the hot pressing time is too short, the hot melt adhesive film cannot be spread out well, so the time is too long or too short.
The temperature, pressure and time described above are the three elements of hot pressing that our adhesives pay attention to when bonding. These three elements are the process parameters that we must consider and determine when using hot melt adhesive film products. The secret to the film process.