The third layer is adhesive, which is mainly used to provide adhesion with the car paint surface in order to perfectly blend the invisible car cover with the car paint.

Coating

Coating is the technological strength of paint protection film structure and the first line of defense for protecting car paint. The coating is located on the outermost side of the membrane, in direct contact with the outside world. The function is to prevent the infiltration and erosion of foreign pollutants, and provide good automatic scratch repair function, providing better bright luster.

Type 

From the perspective of car clothing technology and function, coatings can be divided into two categories: 

① Hydrophilic coating vs Hydrophobic coating 

Hydrophilic coating: By flowing water, the oil, dust, and dirt on the surface of the car clothes can be washed away, achieving the effect of splashing water and self-cleaning. 

Hydrophobic coating: By sliding water droplets, the dust on the surface of the car clothes is carried away, achieving the purpose of self-cleaning. There are similarities and differences with the lotus leaf effect.

② Functional coating 

Second repair coating: Scratches can disappear automatically in a short period of time at room temperature, but due to the active state of the coating molecules for a long time, the activity loss is fast, so the repair effect of the coating cannot be maintained for a long time. When the coating molecules lose their activity, the aesthetics of the car clothes will be seriously affected. 

Hot repair coating: It requires heating to achieve scratch repair effect. At room temperature, the molecular activity is low and the fluidity is not strong. As the temperature increases, the molecular activity increases, achieving an accelerated self-healing effect. The thermal repair coating only becomes active when exposed to heat, which can maintain its molecular activity for a long time and maintain the scratch repair ability of the car clothing.

Base material 

The substrate is the main part of the paint protection film structure, located between the coating and adhesive layer to provide good transparency and toughness. The substrate is a solid barrier that prevents the car paint from being scratched and damaged, and maintains the natural color of the paint surface.

Type 

The main popular car clothing material in the current market is TPU, which is further divided into aromatic and aliphatic types: 

① Aromatic TPU 

The yellowing of aromatic TPU is an inevitable characteristic, as ultraviolet radiation causes an immutable change in some of its structures, resulting in the formation of chromophores. The color changes from transparent to yellowish, and the degree of yellowing can ultimately reach 40% -50%. 

② Aliphatic TPU 

It can be understood as a variant of aromatic TPU, and the difference between the two is that the yellowing structure of the latter is removed, allowing it to maintain its original transparency under long-term ultraviolet radiation, and its final yellowing degree generally does not exceed 10%.

Adhesive layer 

The adhesive layer is an auxiliary part of the invisible car body structure, which is used to tightly fit the car body and paint surface. The adhesive layer affects the service life of car clothing and the safety of car paint.

The influence of superior and inferior glue 

① Poor quality glue

Unstable viscosity. During installation, it is easy to peel off the adhesive and leave adhesive marks on the car paint. Prolonged use can cause delamination, delamination, and foaming. The residual adhesive during peeling may also penetrate into the interior of the car paint, and even easily remove the car paint when peeling off the film. 

② High quality glue 

When pasting, the viscosity is low (can be adjusted repeatedly without leaving any marks), and after the water evaporates, it has the characteristic of high adhesion. Make the car paint and car clothes tightly adhere to each other, without peeling off edges. When peeling off the film, it is more convenient to remove it and will not form residue on the surface of the car paint, making the car paint safer.