HMA （hot melt adhesive）The hot melt adhesive is attached to the surface of the aluminum foil. When making the air duct, the materials are heated in the oven to form a sticky bond.Hot melt adhesive is made of PVC or PE。
The aluminum foil has stiffness and will not retract after installation, which can maintain the flatness of the hose and play a certain flame retardant role.
PVC has high elasticity, is not easy to be damaged, and has high temperature and fire resistance after being compounded with aluminum foil.
PET increases tensile strength, making the hose less prone to breakage and moisture-proof
