Why use hot melt adhesive film for insole bonding?

In the traditional manufacturing process, glue is usually used to bond the insole. However, due to a large amount of solvent in the glue, the laminated product has an apparent pungent smell, which is neither environmentally friendly nor harmful to health. Therefore, Foamwell products are selected hot melt adhesive film for insole bonding.

Hot melt adhesive film is an adhesive that is solid at room temperature, melts at high temperature, and has viscosity. It does not contain solvent, is colorless and odorless, and is an environmentally friendly polymer product. It is used in clothing and underwear, children's products and water treatment, shoe materials, and other fields are widely used, easy to use, and not easy to seep glue. At present, or due to the influence of policies or the improvement of quality, more and more factories use hot melt adhesive films to bond insoles, which has become the industry's future development trend.

EVA and low-temperature TPU hot melt adhesive films are more suitable for insole bonding

In the application of insole bonding, it is more suitable to use the hot melt adhesive film of EVA composition and low-temperature TPU composition, depending on the material of the insole foam. If the bottom material is EVA foam, use the hot melt adhesive film of EVA composition. It is more suitable, and if it is polyurethane (PU) foam or only the bonding and compounding of two fabrics, it is recommended to choose a hot melt adhesive film with TPU composition because the same-sex attracts. The Chinese name of the EVA component is vinyl acetate copolymer, which has many of the same molecules as EVA foam;. In contrast, the Chinese name of the TPU component is polyurethane, which has many of the same components as polyurethane (PU) foam, so choose a hot melt with similar components. The adhesive film is more suitable for bonding, and TPU hot melt adhesive film has better adhesion (viscosity) to cloth.

The melting point of EVA and low-temperature TPU hot melt adhesive films is not high, only about 80 °C, and the actual operating temperature can reach about 80-100 °C. This is also to better protect the adhered material from damage and improve production efficiency. Due to the high melting point of the hot melt adhesive film, the corresponding operating temperature will be higher, and it is easy to cause damage to the foam during lamination and affect the quality of the product, such as flattening the material or causing the melting of the foam.

How to use hot melt adhesive film in the bonding of insole

In the insole bonding process, it is usually a one-time bonding. That is, knitted fabric, hot melt adhesive film, foam, and three layers are compounded together, which is also to improve production efficiency effectively. When choosing a hot melt adhesive film, there is no need to choose a release paper, just a bare film. How to use: Place the hot melt adhesive film between the knitted fabric and the foam, and then use professional pressing equipment to heat from the side of the knitted fabric (this is because the foamed side is thick and challenging to conduct heat), and the heat passes through the knitted fabric Conduction to the middle layer of hot melt adhesive film will make it melt, so that the cloth and foam can be bonded together, and then wait for it to cool to complete the subsequent punching and other related processes; and the production equipment used by some manufacturers is grinding. The difference from the above is that the insole foam or rubber is directly formed in the abrasive tool, similar to the production process of special gloves. The subsequent lamination with the cloth also uses this abrasive tool. In combined use, it is necessary to use professional equipment to back the hot melt adhesive film to one side of the fabric to form a self-adhesive cloth (one side of the cloth, one side of the adhesive), and then the second lamination with the bottom foam/rubber material.