What are the selection requirements and principle production of protective film? The selection requirements of the protective film will generally consider: the reasonable combination of the thickness and viscosity of the protective film, the tensile strength and elongation of the protective film, to ensure that the flexibility and strength of the protective film can meet the requirements.

Selection requirements for protective film
(1) Reasonable collocation of thickness and viscosity.

(2) The tensile strength and elongation of the protective film to ensure that the flexibility and strength of the protective film can meet the requirements.

(3) The ultimate principle of protective film selection: fully test.

(4) Different surfaces require different viscosities.

(5) Different materials with similar surfaces may also require different viscosities.

(6) The subsequent processing steps are the key to determining the viscosity. Subsequent processing generally includes bending, stamping, cutting, drilling, thermoforming, etc.





The principle of protective film production
1. The principle of protective film adhesive (glue)
(1) A polymer with viscoelasticity.

(2) Film: The adhesive layer can be in close contact with the surface of the adherend and flow into the groove of the adhered surface as much as possible, so that the effective contact area is increased.

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

(4) Adhesion performance (stickiness): T<A<C<K. Tack, adhesion, cohesion, and keying.


2. The main factors affecting stickiness
(1) Wetting: The pressure-sensitive adhesive can only achieve close contact with the surface of the adhered object, creating conditions for physical and chemical combination.

(2) Molecule movement and diffusion: Pressure-sensitive adhesive molecules will move to the surface of the material to be adhered. When the distance between the two is less than 5A, physical and chemical bonding will occur.

(3) Penetration: The adhesive layer flows and penetrates into the groove and the gap under a certain pressure, so that the contact area between the two is increased. At this time, a mechanical bonding force is generated between the adhesive and the material to be adhered.


3. Preparation of substrate film
Blow molding, casting, calendering.


4. Surface treatment of substrate film
(1) Corona treatment: form polar reactive groups and form very fine potholes.

(2) Coating: The liquid glue is evenly coated on the substrate film and dried initially.