Effect of laser pre-treatment on the properties of dyeing with natural dyes of wool fibers

The consumption of water and energy used for dyeing and finishing operations in the textile industry forms essential environmental concerns. Laser technology has the potential to increase environmental sustainability by offering alternative solutions to traditional textile wet processes, significantly decimating the energy and wastewater that is used. In addition, by making the order short-term with rapid production, laser technology can offer digital design capabilities. In addition, wool fiber has many advantageous qualities in textiles such as thinness, length, moisture permeability, and crease-resistance, and due to its porous and permeable structure, wool absorbs sweat and releases it slowly during evaporation, so that people wearing wool feel less cold in winter and evaporation keeps them cool in summer. However, it can become felted easily in humidity, temperature and alkaline (basic) environments and it is undesirable in its use. Chlorination is usually performed as a pre-treatment for felting control. The chlorination process includes a large use of chemicals and a large amount of water. In this thesis study, CO2 laser treatment is applied to woolen fiber fabrics at different laser firing frequencies (number of laser dots per inch) on only the front side or both the front and back sides (both sides of the fabric) to determine the various properties of woolen fabrics such as strength, stiffness, dimensional change, etc. In addition, for a sustainable study, the wool fabrics were dyed with natural dyes along with natural mordant. Moreover, color and color fastness properties of dyed fabrics were examined. When the dpi degrees of the laser process increase and/or when laser treatment is applied to both sides of the fabric, the weft density, warp density, there was a slight increase in the thickness and on the fabric weights as a result of laser treatment. There was also less dimensional change and darker dyeing. Although the laser treatment slightly increased the fabric stiffness, the stiffness after natural dyeing was close to untreated wool fabric. Exposure of wool fiber to high laser firing frequency levels (higher dpi degrees) by laser energy caused stiffer handle, loss of strength and decrease in color fastness.