The primary purpose of the shading film is of course insulation and UV protection, but in the unqualified products, the four major indicators will affect heat insulation and safe driving. According to experts, the transmittance of visible light indicates the percentage of visible light passing directly through the film glass in the incident sunlight. The visible light transmittance should be 78%, and the measured value of the visible light transmittance of 3 batches is less than 78%, which will affect the driver’s observation on the driving environment and reduce the ability to identify the things outside the window.

Ultraviolet transmittance refers to the ratio of the transmitted ultraviolet spectral radiation flux to the incident ultraviolet spectral radiation flux. According to the standard, the UV transmittance should be 1%. The UV transmittance of the 5 batches of the products is unqualified, which makes a part of the ultraviolet light storage and penetrating the sun film in the form of absorption and radiation, which leads to the rapid attenuation, fading and blurring of the optical performance of the sunshade film, and greatly shortening the service life of the sunshade film.

The quality film should be able to see clearly at night 6 meters away from the objects, and the poor film will have a foggy feeling. You can wipe the surface of the film with alcohol or gasoline, and it is easy to fade the poor quality film. There is a small way to put a piece of glass with a car sticker on the iodide lamp, and the hand feels no heat is a good film, and the immediate hot feeling is a problem of heat insulation. It is a poor film.