The first is the effect of temperature. Some experimenters have done experiments. Due to the bubbles, the protective film is supported by the bubbles at 80 ° C. That is, the protective film has begun to tear slowly under high temperature conditions. If the heat resistance or cohesiveness of the adhesive of the protective film is not good, residual glue or shadows tend to appear around its bubbles. Usually, the place where the shadow appears is where the air bubbles forming the protective film form.
The other is that this usually happens on protective films containing emulsifiers. After the emulsifier migrates, there will be shadows. The surfactant will act as an external plasticizer in the coating film, making the coating film soft and elastic. This is advantageous if the plasticizer is distributed uniformly during coating. However, due to the surface activity of the surfactant, the molecules migrate from the bulk phase and aggregate on the surface, and tend to concentrate at the membrane-air interface, thereby forming a shadow.
The longer the time, the larger the contact surface between ordinary small bubbles and air, the higher the possibility of shadow formation. Therefore, please try to avoid small bubbles, and use a good quality protective film with a uniform coating, which can delay the appearance of dark shadows.https://www.pe-protectionfilm.com/