Study On Mechanism And Inhibition Of Light-induced Discoloration Of Painted Dyed Veneer

I-214 Popular (Populus euramericana Dodo Guineir cv. 'I-214') and Mongolian Scotch pine (P. syvestris var.mongolica Litv.) were used as test materials for veneers. The veneers were dyed respectively by acid red GR and acid blue. Watercraft acrylic resin and Polyurethane resin were used to paint veneers and dyed veneers by direct painting and free film covering. The painted veneers and painted dyed veneers were placed into Xenon fade meter (X25F), and then were radiated at different time in 0-100h. The effects of experimental factors and the laws of light-induced discoloration of veneers under direct painting method and free film covering method were investigated and compared. In the meantime, the test paints were modified with nano-TiO2 and UV absorption agent. The dyed veneers painted by modified paints were radiated in Xenon fade meter. The laws of light-induced discoloration of dyed veneers painted by modified paints were studied. The inhibitive effects of the modified paints on painted dyed veneers were investigated as well. The mechanisms of light-induced discoloration of painted dyeing veneers were investigated by Fourier infrared spectrometer. The main conclusions and innovations are as follows:1. The laws of light-induced discoloration of untreated veneers, dyed veneers and painted dyed veneers were systematically studied. The SAS statistical software was used to analyze the prominence of light-induced discoloration factors of dyed veneers and directly-painted dyed veneers. The results indicate that under Xenon's radiation both dyed veneers and painted dyed veneers are easy to discoloration. The laws of light-induced discoloration of untreated veneers and directly-painted veneers are similar. For dyed veneers or directly-painted dyed veneers, the variation of the light index L* and the total color difference AE*ab (the degree of light-induced discoloration) are similar, but the changes of the color indexes a*-b* are different. The type of dyes is a major factor influencing light-induced discoloration of painted dyed veneers. After 100h radiation, the total color difference of dyed veneer by acid blue (â–³ E*ab=27.67) is greater than that by acid red GR (â–³E*ab=12.21) ? The types of dyes and paints are two major factors influencing light-induced discoloration of directly-painted dyed veneers. After 100h radiation, the total color difference of directly-painted dyed veneer by...