The states of existence of acrylic glue and silica gel are different. Thus their effects are different.
Most of the PET protective films we use are coated with silica gel. Compared to acrylic glue, silica gel is much widely used. For example, the PET protective films that are commonly used on screen is required to be coated with silica gel. Besides, the temperature that silica gel could bear is higher than that acrylic glue could. Acrylic glue is mainly used in packaging of high-light products or used as the switch of thin film. It's quite cheap and convenient.
When we buy a roll of PET protective film, how can we know whether acrylic glue or silica gel is used in it? The simplest and fastest way is to scratch the adhesive side of the film. If there is no glue or powder, then it's silica gel, otherwise it's acrylic glue. Therefore, silica gel is also called "glue with no powder". The manufacturer who use adhesive PET protective films can use this method to know whether acrylic glue or silica gel is used in the film they are using.
