Hot melt adhesive films have been applied in many indus […]
Hot melt adhesive films have been applied 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 strong bonding effect for hot-melt adhesive films is a problem that many users care about.
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, temperature is the primary condition for good bonding of hot melt adhesive film.
The melting temperature of different materials of hot melt adhesive film is different, that is, there are high and low temperatures. If the heating temperature is higher than the temperature required for the hot-melt adhesive film, the hot-melt adhesive film will melt too fast or over-melt, so that the glue will easily penetrate into the material to be glued. Especially in some textile fields, if the temperature is too high, there will be some penetration of the glue, which will affect the bonding effect.
If the bonding temperature is too low to reach the recommended use temperature of the hot melt adhesive film, then the hot melt adhesive film will melt incompletely or too slowly, so that within a certain period of time, the glue will not be able to melt. It spreads well into the adherend, and it cannot form a good bond.
When we are bonding 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 to enable the melted glue to spread on the surface of the adherend as soon as possible, because the glue cannot continue to spread once the hot melt adhesive film is cooled.
At the same time, applying a certain pressure can make the glue form a uniform glue layer on the surface of the adherend. Some adherends have their own stress, and they need to be cold pressed after hot pressing, which can effectively avoid bonding failure due to stress release
Temperature and pressure are the two essential elements for the hot melt adhesive film to obtain a good bond, and another important element is the hot pressing time. Because it takes time to heat the hot-melt adhesive film, it also takes time to spread the hot-melt adhesive film on the surface of the adherend after it has melted. A long hot pressing time will cause the adhesive to penetrate excessively, and the hot melt adhesive film will not spread well if the hot pressing time is short, so it will not work if the time is long or short.