Classification by protective film Market:

1) Traditional protective film: such as galvanized steel plate protective film, color steel plate protective film, glass plate or plastic sheet protective film, etc. Most of these traditional protective films belong to applications with low added value, have low requirements for performance and crystal point, and are mostly adhesive protective films.

2) Protective film for flat panel display: the application scope includes flat panel display, TFT-LCD Module, backlight module, glass substrate and various optical components, such as polarizer, color filter, etc. The application of this kind of film has high requirements for viscosity and additional protection points.

3) Protective film for high-tech electronic industry: such as the protective film for dry film or wafer grinding process. This kind of protective film usually needs to be produced in a dust-free room, and the requirements for crystal point are very strict. Only a few protective film manufacturers have sufficient technical capacity to meet these requirements.

2、 Production principle of protective film:

1. Principle of protective film adhesive (glue)

Viscoelastic polymer

Sticking film: the adhesive layer can be in close contact with the surface of the adhered object and flow into the groove of the adhered surface as much as possible, so as to increase the effective contact area

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

Bonding performance (adhesion): T < a < C < K

Tack, adhesion, cohesion and keying

2. Main factors affecting viscosity

Wetting: only when the pressure-sensitive adhesive has good wetting with the surface of the adhered object can it achieve close contact and create 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 them is less than 5a, physical and chemical bonding will occur

Penetration: the adhesive layer flows and penetrates into the groove and gap under a certain pressure, so as to increase the contact area between them. At this time, a mechanical bonding force is generated between the adhesive and the bonded material

3. Preparation of substrate film

Blow molding, casting and calendering

4. Surface treatment of substrate film

Corona treatment: form polar reaction groups and form very fine pits

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