The Study On The Improvement Of Light Fastness Of Polyester Fabrics With UV-absorbers

As a result of the more and more serious destruction of the ozone layer which was caused by the intensification of environmental pollution, the ultraviolet radiation come to the surface of earth from the sun has been growing all the time, especially for the short wavelength ultraviolet radiation which would take more damages. Then the threat caused by UV radiation to the materials used outdoors including textile would get much more serious. Several methods should be taken in order to prevent the increased bleaching of dyed fabrics caused by the much more seriously UV radiation. UV-absorbers have been used in this research in order to improve the light fastness of dyed polyester fabrics.UV-absorbers were added into the dyeing bath of polyester fabrics and were dyed on these fabrics through the process of high temperature and high pressure just like disperse dyes after they were grinded into small particles and stable dispersion because these UV-absorbers used for dyeing polyester fabrics were hydrophobic materials. Sand milling process was taken in this research in order to grind these hydrophobic UV-absorbers into small particles. Several factors which would affect the efficiency of sand milling have been discussed in this research such as the time, temperature, filling rate of sanding medium, and the type and amount of dispersant, and the best sanding process has been gotten after these work.The dyeing characters of different type UV-absorbers have been discussed in this paper, it was found that these UV-absorbers with small molecule weight and simple structure would have a good performance when they were dyeing polyester fabrics but these UV-absorbers with too large molecule would be difficult to uptake on the polyester fabrics. The mutual influence of UV-absorbers and disperse dyes when they were dyeing polyester in the same bath has also been discussed, it was found that the uptake rates of both UV-absorbers and disperse dyes would be decrease compare with the uptake rates when they were dyeing polyester individually, which would be caused by the compete of UV-absorbers and disperse dyes in the same dyeing bath. There have no differences in the color of fabrics dyeing by UV-absorber and dye together and by disperse dye alone, but there would be a slightly decline of the K/S value of the former as a result of the competition of UV-absorber and dye.It was also found that in this research the ultraviolet protected factors of the polyester fabrics would be enhanced obviously after they were dyed by UV-absorbers, and the light fastness of dyed polyester fabrics would increase about 1 level.In a word, the hydrophobic small molecules UV-absorbers could be standing decentralized and then could be dispersed into a stable dispersion with the help of dispersant. These dispersions could be added into the dyeing bath of polyester fabric and could be uptake on these fabrics through the process of high temperature and high pressure. The ultraviolet protection character and the light fastness of dyed polyester fabrics would be enhanced after they were dyed by UV-absorbers and UV-3 has the best effect among all the UV-absorbers used in this research.