During the coating process, it is essential to ensure that polymer films exhibit excellent formability. Polymers need to possess good thermoplastic adhesion to prevent cracking during high-temperature sterilization and curing processes, while also ensuring excellent barrier properties to avoid corrosion of the metal substrate. Therefore, the selection and development of films are crucial. Surface modification methods, such as increasing the content of polar groups on the film surface, can enhance the adhesion strength with the metal substrate.
Corona treatment is a commonly used surface modification method. This method is easy to control, consumes less time, and is fast; however, after a period of corona treatment, the surface groups of the film will rearrange, resulting in a short duration of corona effect and a significant reduction in surface energy. Therefore, films treated with corona must undergo composite bonding operations as soon as possible.
