How does color coating give polyester film unique optical properties?

At the forefront of materials science, color-coated metallized biaxially oriented polyester film has attracted much attention for its outstanding performance. The uniqueness of this material is largely due to its special color coating process, which is significantly different from the ordinary dyeing process and brings precise and unique optical effects to the film.

As a basic material, biaxially oriented polyester film (BOPET) itself has good optical properties, and its transparent texture provides an ideal carrier for subsequent processing. Color coating is a key upgrade on this basis. It uses special coating formulas and precise coating technology to give the film extraordinary optical performance.

The coating formula used for color coating is carefully developed and formulated. These coatings are not a simple mixture of ordinary pigments, but a complex system composed of multiple functional ingredients. Among them, the pigment particles are specially treated with high purity and narrow particle size distribution, which allows them to be evenly dispersed on the surface of the film, thereby ensuring the consistency and stability of color presentation. Special binders are added to the coating, which not only firmly attach the pigment to the film surface, but also form chemical bonds with the film substrate to enhance the adhesion and durability of the coating. This special binder forms a tough and flexible film structure after curing, which can not only resist friction and wear in daily use, but also adapt to thermal expansion and contraction under different environmental conditions, ensuring that the coating will not peel off or crack.

Precision coating technology is another key factor in achieving color coating effects. During the coating process, advanced coating equipment and process control methods are used. For example, the use of high-precision coating molds can accurately control the coating thickness of the coating on the film surface, and the deviation can be controlled within a very small range. This precise thickness control is crucial for color uniformity, because coatings of different thicknesses will cause different degrees of interference and scattering when light propagates through them, which in turn affects the color presentation effect. In addition, parameters such as speed, temperature, and pressure during the coating process are strictly optimized and precisely controlled to ensure that the coating can be evenly spread on the film surface to form a dense and smooth coating.

These carefully formulated coatings form a uniform and strong coating on the film surface, which plays an important role in optical performance. First, they can accurately present a variety of bright and long-lasting colors. Due to the high purity and uniform dispersion of pigment particles and the precise control of coating thickness, the film can accurately restore the original color of the coating and present extremely bright tones. Moreover, thanks to the special coating formula and good adhesion, these colors are not easy to fade under long-term use and lighting conditions, and can maintain long-term brightness.

Secondly, the coating can also absorb and reflect light in a specific way. Different color coatings have different absorption and reflection characteristics for light, which is determined by the chemical structure of the pigment. For example, the red coating mainly absorbs other visible light bands except red, and strongly reflects red light, thus presenting a bright red color. This selective absorption and reflection of light not only enables the film to present rich colors, but also can adjust the transmittance and reflectivity of light to a certain extent. In some application scenarios, such as packaging, by rationally designing the optical properties of the coating, the film can reflect light of a specific wavelength, enhance the visual appeal of the product, and absorb or reflect harmful light such as ultraviolet rays to protect the items in the package from light damage.

In practical applications, these unique optical properties of color-coated metallized biaxially oriented polyester film have shown great advantages. In the high-end packaging industry, its bright and lasting colors and special ability to control light can make products stand out on the shelves and attract consumers' attention. In the field of optical devices, by precisely controlling the optical parameters of the coating, the strict requirements of different optical lenses, display backlight modules, etc. on the optical properties of materials can be met.
The color coating process gives the metallized biaxially oriented polyester film unique optical properties through special coating formulas and precise coating technology, making it play an indispensable role in many fields, and with the continuous development of materials science and coating technology, its application prospects will be broader.