Color technology of automotive color changing film: from color matching principle to optical effect optimization

The visual appeal of car color changing film lies in its color expression, and the core of color technology lies in the integration of pigment selection, coating process, and optical principles. This article will analyze the color technology of color changing films from three aspects: molecular structure, color matching methods, and environmental adaptability.

1. Pigments and coating technology

The color of the color changing film is mainly determined by the pigments in the substrate and the surface coating. The current mainstream pigments include metal powders, pearlescent mica, and nanoscale pigments:

Metal powder pigment: Metal such as aluminum and chromium are evaporated and deposited on the surface of the substrate through vacuum coating technology, forming a mirror reflection effect. For example, a certain brand's "silver electroplating" color changing film adopts a multi-layer aluminum film composite process, presenting rainbow colored spots at specific angles.

Pearlescent mica pigment: Based on natural mica, wrapped with titanium oxide or iron oxide coating, it produces pearl luster through interference effect. The control of particle size is crucial - when the particle size is less than 20 μ m, it presents a soft pearl like appearance, while when it is greater than 50 μ m, it may produce a grainy feel.

Nano color paste: the organic dye is wrapped in silica nanoparticles by the sol gel method to improve the weather resistance. According to data from a certain laboratory, after 1000 hours of ultraviolet irradiation, the color difference Δ E of the nano color paste modified film is only 1.2, far lower than the 3.8 of traditional color paste.

2. Color matching system and process

The color adjustment of the color changing film needs to balance color accuracy and construction feasibility. The mainstream technologies include:

Spectrophotometer assisted color adjustment: Use X-Rite colorimeter to measure the color data of the original car paint, and generate a color correction film formula through algorithm. For example, a certain brand's color matching system can match a color changing film with a color difference Δ E ≤ 1.5 with Porsche's "Miami Blue" within 15 minutes.

Multi layer co extrusion coating technology: Different colored layers are synchronously extruded through multiple sets of screw extruders to form a gradient effect. A certain factory adopts a five layer co extrusion process to achieve a 180 ° gradient transition from "Midnight Purple" to "Starry Silver".

Texture transfer printing technology: Embed concave convex textures in the coating, and transfer patterns such as wood grain and carbon fiber to the film surface through rolling process. In a certain case, the surface roughness Ra value of the carbon fiber patterned color changing film is controlled at 0.8-1.2 μ m, which is comparable to the realism of the original material.

3. Optical effect optimization

The optical properties of color changing films directly affect their performance in different environments:

Anti glare coating: Coating the film surface with a fluorinated polymer to reduce reflectivity to below 5%. A certain test showed that after installing anti glare color changing film, the glare intensity of the oncoming lights during night driving decreased by 67%.

Heat reflection technology: By doping indium tin oxide (ITO) nanoparticles, the film material is endowed with thermal insulation function. The infrared blocking rate of a TPU color changing film reaches 82%, and the temperature inside the car is reduced by 8 ℃ compared to when the film is not applied.

Self cleaning coating: Using the lotus leaf effect principle, micro nano structures are constructed on the membrane surface. In a certain experiment, the contact angle of water droplets on the surface of the self-cleaning color changing film reached 152 °, and the amount of dust adhesion decreased by 79%.

Technical Challenges and Trends

The current color changing film technology faces two major challenges: one is the construction accuracy of complex patterns (such as camouflage and geometric splicing), and the other is the balance between color persistence and environmental friendliness. Future technology will focus on:

AI color grading system: By analyzing millions of color databases through deep learning, it achieves "one click color grading".

Biobased pigments: Replace traditional chemical pigments with plant dyes to reduce VOC emissions.

Intelligent color changing film: integrating electrochromic or photochromic materials to achieve film color change with the environment.