The effect of recycled fibers from indigo dyed yarns on yarn and fabric performance

The importance of sustainability in the textile industry is increasing day by day due to meeting the fiber needs of the increasing world population and the gradual decrease in agricultural areas. The most preferred fiber in denim fabrics is cotton fiber. Due to the increasing share of cotton in the textile market, sustainability studies are also carried out on denim fabrics. The thesis study aims to provide a sustainable denim production process by recycling indigo dyed waste yarns. Waste indigo dyed yarns obtained from the denim mill were turned into fibers by mechanical recycling. The resulting fibers were mixed with 30%, 50% and 70% cotton fibers in the blend to produce yarn, and the test values of the blended yarns were compared with 100% cotton yarns. It has been observed that as the rate of recycled fiber in the yarn increases, the yarn properties are slightly negatively affected, as expected. It was concluded that the raw material cost of 1 kg of yarn production decreases as the recycle rate increases. 3/1 Z twill woven denim fabric was produced from the produced threads, and elasticity, tensile strength, tear strength, grammage, warp shrinkage, weft shrinkage, air permeability, softness and color fastness to rubbing tests were applied to the fabrics. It has been observed that the use of recycled fibers does not have a negative effect on the fabric's elasticity, weight, warp and weft shrinkage and color fastness to rubbing. It has been determined that the tear and tensile strength of fabrics produced using recycled fiber in the yarn is slightly reduced compared to fabrics produced using 100% cotton yarn. In the life analysis evaluation, the effects of values such as resource depletion, global warming, toxic effect on human life, toxic effect on freshwater life, toxic effect on marine life, toxic effect on terrestrial life and total water use were examined. As the recycled fiber ratio in fabrics increased, life analysis values were positively affected in parallel. Keywords: Pre-Consumer, Indigo Spinning, Recycled Yarn, Life Cycle Assessment