Fibres and Textiles (2) 2019 48 STUDY OF INFLUENCE OF THE PREPARATION METHOD ON THE LIGHT FASTNESS OF COTTON KNITTED FABRIC Olga Semeshko, Tatyana Asaulyuk, Nataliya Skalozubova and Yulia Saribyekova Kherson National Technical University, Berislav highway 24, 73008 Kherson, Ukraine solgaya@gmail.com Abstract: The main goal of this research is to study the effect of preparation methods (boiling, bleaching, combined boiling and bleaching principle, developed preparation principle) on the quality of cotton knitted fabric, sorption capacity in relation to reactive dyes and light fastness of colour. The quality of the preparation was evaluated in terms of capillarity, degree of removal of waxy substances, whiteness, breaking load and sorption of reactive dyes using traditional methods. The light fastness of the obtained colours was evaluated after exposure of Light Fastness Tester (Mercury-Tungsten Lamp) RF 1201 BS («REFOND») with a PCE-TCR 200 colorimeter. It has been established that high indices of light fastness of colours obtained on cotton knitted fabric with reactive dyes are ensured by the developed preparation principle. Keywords: light fastness, cotton knitted fabric, reactive dyes, preparation, dyeing. 1 INTRODUCTION Light fastness of colour is an important indicator of quality for textile materials intended for sportswear, T-shirts and clothes for children. Preparation of textile materials is an important stage, since the efficiency of dyeing processes and final finishing, and hence the quality of the textile material as a whole, depends on its implementation [1, 2]. Since the range of fabrics for summer clothing is widely represented by cotton knitwear, the study of the effect of its preparation on the light fastness of colors is an actual task. The process of cotton knitwear preparation is the most technologically complex, energy-consuming and labor-intensive stage of finishing works. Therefore, technologically and scientifically-based exclusion of some operations is relevant when producing high quality cotton knitted fabrics with low cost. It is known [3, 4] that the preparation includes a set of processes that ensure the removal of natural impurities (mainly waxy substances) and substances deposited on the fabric during their manufacture (oiling agents) from grey knitted fabric in order to give high capillarity and whiteness. In the course of preparation, the following aggressive factors influence on textile materials: 1) alkaline boiling solution at high temperature, which is the cause of the destruction of cellulosic material under the influence of atmospheric oxygen; 2) peroxide compounds used in bleaching and leading to a decrease in the strength and degree of polymerization of cellulose. The milder conditions will be during the preparation of textile materials, the more will be preserved strength and natural properties of cellulose, and clothing will have a higher quality [5-7]. There is no direct relationship between high indices of light fastness and other indicators of the resistance of colors to physical and chemical effects (washing, dry and wet crocking). However, it can be argued that, in general, the quality of color depends on the rate of diffusion and sorption of the dye, which are determined by the physicochemical properties of the fiber [8]. It is known [6, 7] that on a fabric that has been maximally cleared of natural and technological contaminations, it is possible to get pure and bright colors that are resistant to washing, dry and wet crocking. But it should be noted that the effect of the degree of preparation on resistance of obtained colours to the action of light was not investigated on cotton knitted fabric with different degrees. 2 THE GOAL OF THE STUDY The goal of present work was to study the influence of the preparation method of cotton knitted fabric on its quality, sorption ability in relation to reactive dyes and on the stability of colours to the action of light.