Thesis Details

Thesis Title: The effects of varying density during package build to optimize levelness on package dyed yarn
Thesis Author: Victor Mattison
Abstract: Package dyeing is still a widely used method for coloring yarns because of its unique patterning possibilities, its speedy reaction to market demands and its batch size flexibility. The market continuously demands that package dyers meet the challenge of equally and evenly penetrating dye liquor to all parts of a yarn- package to achieve levelness. This can be accomplished by optimizing the yarn package as well as the dyeing process. Package optimization can only be achieved during the winding operation. It is during this process that the density throughout the package, i.e., "density profile," is determined. The "density profile" of a package is one of the most important package characteristics that affects levelness because it influences the flow of dye liquor through every successive yarn layer within a package. An ideal package "density profile" would provide minimum resistance and even penetration of dye liquor throughout the yarn package. The textile industry, however, has not been successful at winding the ideal "density profile" because of machine limitations. This research was conducted to identify the ideal "density profile" that would produce total shade uniformity throughout a yarn package. A prototype Appalachian CONP AR Winder was used to vary yarn tension in a predetermined arrangement to produce twenty-seven different package "density profiles." The two fiber/dye systems investigated were cotton direct and polyester disperse. Each fiber/dye system was dyed using typical industry dye procedures, without using any enhancing chemicals such as carriers or levelers to promote a worst case scenario. A five percent difference in KlS values was used as the maximum allowable tolerance for determining levelness. Based on these processing parameters, the following results were disclosed: 1. Density profiles of yarn packages simulated the way in which tension was profiled throughout the yarn package. However, the variations in package density were not identical to the variations in yarn tension. 2. The air flow through cylindrical yarn packages was influenced most by the innermost winding zone. Density changes in the yarn layers adjacent to the tube had a greater effect on air flow and depth of shade than density changes in other winding zones. 3. Within both dye systems investigated, variables more influential than the density profiles influenced the levelness properties of the yarn packages. The variable which most negatively influenced levelness was the flow leak between packages. Another negative effect of flow leaks was the discernable trend between package spindle placement and package levelness; the potential for levelness decreased from top to bottom of the spindle. 4. The inherent tendency for the traverse to increase during precision winding caused the cotton yarn packages to bulge at the edges which adversely affected their backwinding performance. However, the backwinding performance of the polyester yarn packages was not adversely affected because the yarn packed more densely.