Many people will ask whether there is any relationship between the bonding effect of hot melt adhesive film and the thickness of the hot melt adhesive film? Because the thicker the film is, the greater the amount of adhesive applied, and the greater the amount of adhesive applied, the higher the cost, so it is worthwhile to mention this issue.
In fact, for many materials, especially porous materials, such as textiles, if the hot melt film thickness is too thin, the amount of glue is not enough. Only a small part of the melted glue can penetrate the material, at this time, although a certain bond strength can be formed, but not as much as the amount of glue when the bond strength.
But if the hot melt adhesive film is too thick, that is, when the amount of glue is too much, then the glue under pressure will penetrate through the substrate we need to bond, resulting in contamination of the surface of the substrate. However, this may not affect the bonding strength, but it leads to more serious problems, resulting in a porous glue. The entire bonding operation fails.
For the strong permeability of textiles, too thick hot melt adhesive film will have these problems. What is the situation for surfaces that are not permeable to be bonded? For example, metal surfaces do not have adhesive penetration, and when the hot melt adhesive film is too thick, there is no problem with adhesive penetration. However, during the gluing process, the excess glue is often squeezed out through the bonding interface under pressure, resulting in a waste of glue and causing pollution to the machine and equipment, which causes a lot of trouble. Moreover, too thick hot melt adhesive film will lead to the too thick layer of adhesive between the bonded objects, which will lead to the decrease of bond strength for the hot melt adhesive film with insufficient cohesion.
Therefore, the thicker the film, the better the bonding effect. In many cases, repeated tests are needed to find the most suitable thickness to ensure the bonding strength, save the cost budget, and consider the maintenance of machinery and equipment.
How should you choose hot melt adhesive film？