Sponge materials are often used in actual industrial production, such as insoles, bags, seat cushions, etc., which all involve sponges. Bonding of sponges and other materials can be done using hot melt adhesive films.
So, what are the requirements for the performance of the hot melt adhesive film, which is a special material like a sponge?
What distinguishes a sponge from other materials is that it has a very soft structure and contains porous characteristics. Therefore, when the adhesive is bonded to it, the adhesive needs to be not too thin, and the hot melt adhesive film, as a solid adhesive, is more suitable for bonding sponges.
According to the parameter characteristics of the hot melt adhesive film, we need the melt index of the hot melt adhesive film not to be too high. Once the melt index is too high, the hot melt adhesive film will become very thin and soft after being heated and melted because the higher the melt index, the flow Sex is better. Due to the particularity of the sponge material, if the fluidity of the melted hot-melt adhesive film is too good, it is easy to penetrate too much into the sponge, which often leads to a lack of glue and affects the bonding quality.
In addition, the bonding of the sponge requires that the melting temperature of the hot melt adhesive film should not be too high, especially for some sponges with poor temperature resistance; when the temperature is too high, they are particularly easy to deform under a certain pressure, and the temperature and pressure At the same time, this deformation is often irreversible, which eventually leads to the scrapping of the product.
The hot-melt adhesive films we usually use in sponge composite bonding are EVA hot-melt adhesive films and TPU hot-melt adhesive films, and they are product series with relatively low temperatures. Generally, the maximum operating temperature will not exceed 120 °C.
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