Increasing of the color depth in polyester fiber treated with laser beam

Due to the high refractive index and smooth surface of Polyester fibers, a significant fraction of the incident light is reflected from their surfaces. Thus, dyeing of these fibers with dark colors, mainly black, makes it a difficult tasks. High surface reflectance of Polyester microfibers reveals that appearance of these fibers is seen paler in consequently comparison to the conventional polyester fibers, and consequency it is required to use a latge amount of color to obtain the same color depth. In this study, upon creating surface roughness by laser beams treatment, as a new and environmental friendly method, was investigated to increase the dark color depth in the dyeing of polyester fabrics. An Argon Fluoride laser was used for the irradiation of the samples. The samples were prepared for evaluating the effects of the number of laser pulses, radiation before and after dyeing. The changes in the color depth of samples were analyzed through surface morphology with SEM images, and crystallinity index and crystal size with X-Ray diffraction. The results from spectra data showed that the reflection at different areas of the reflectance spectrum was reduced by increasing the number of laser pulses irradiation. The maximum deep shade in the black chromic of polyester fiber was achieved at the optimum value of 15 laser pulses