Under what circumstances does hot melt adhesive film bonding require cold pressing

We know that hot melt adhesive film needs to be heated to a certain temperature when bonding. At a certain temperature, the hot melt adhesive film will melt, thus wetting the surface of the object to be bonded, and after the melted hot melt adhesive film cools and solidifies again, it will produce a certain strength of bonding force.

Since hot melt films are widely used in the textile industry, they are usually laminated using drum type laminating equipment and are rewound directly after the review is completed. There is no need for cold pressing as a step in this process, but rather relies on the natural cooling of the laminated material to form a bond.

However, for some materials, bonding with hot melt adhesive film without cold pressing is not possible, such as the composite bonding of plates only. This is due to the characteristics of hot melt adhesive film hot pressing. The characteristic of hot melt adhesive film is that it is liquid at high temperature, and only after it cools down and becomes solid does it have adhesive strength. In other words, the bonding strength of hot melt film is not high until it cools down. In this way, materials such as sheets, which have their own thermal stress, will be deformed by the release of thermal stress when they are naturally cooled down, and this application will cause the adhesive layer to separate.

Therefore, when using hot melt adhesive film to bond materials with thermal stress such as sheets, it is necessary to go through a cold pressing step to ensure that the cooling process does not lead to cracking of the adhesive layer and to accelerate the cooling of the material.