[Infrared spectrum characteristics of vehicle body paint]

Two hundred eighty seven samples of vehicle paint were collected, and 940 spectra were obtained by Fourier transform infrared micro spectrometer. The spectral features of varnish, finish layer, and coated layers of different models and different color were analyzed, and the spectra similarities were compared. The results show that the varnish similarity on the same models with different color is 99.5%, and some similar model with the same manufacturer had high similarity. The finish spectra have remarkable differences with different model and different color, and the similarity degree is under 70%. The coated layer similarity varies between 83.33% and 96.91% among the common lacquer putty, and it ranges between 70.12% and 96.44% among the water-based lacquer putty. The metal components of paint will influence the spectrum characteristics. The spectra of the vehicle paint will change with the usage time.