The protective film can be divided into digital product protective film, automobile protective film, household protective film, food fresh-keeping protective film, etc. With the popularity of digital products such as mobile phones in China, protective film has gradually become a general term of screen protective film, and its functions in the field of screen protective film are also various, the first high-definition scratch proof, to the present day, glauke, 180 degree and ok8 functional protective film in Hong Kong are favored. From the earliest PP material to the current popular ar material, the material has experienced more than five years of development, and is gradually accepted by the majority of mobile phone groups.

1. Principle of protective film adhesive (glue): viscoelastic polymer

Film: the adhesive layer can be closely contacted with the surface of the adherend and flow into the groove of the adherend surface as much as possible, so as to increase the effective contact area

Tear film: the adhesive layer has a high peeling resistance. The higher the peeling speed, the higher the peeling strength of pressure-sensitive adhesive

Adhesion: tack, adhesion, cohesiveness and keying

2. Main factors affecting the viscosity of protective film: [protective film]

Wetting: only when the pressure-sensitive adhesive is well wetted with the surface of the object to be adhered can it achieve close contact, creating conditions for physical and chemical combination

Molecular movement and diffusion: pressure sensitive adhesive molecules will move to the surface of the material to be adhered. When the distance bond between the two is less than 5a, biological, physical and chemical binding will be produced

Penetration: when the adhesive layer flows, it penetrates into the groove and the gap under a certain pressure, so that the contact area of the two increases. At this time, there is a mechanical binding force between the adhesive and the adhered material

3. Preparation of substrate film: blow molding, casting and calendering

4. Surface treatment of substrate film:

Corona treatment: formation of polar reactive groups, formation of very fine pits

Coating: apply the liquid glue on the substrate film evenly and dry it preliminarily.