Thesis Details

Thesis Title: The effect of fiber denier and tenacity, and blending method on the pilling of knitted ring, open-end and air jet yarns
Thesis Author: Greg Harding
Abstract: The problem of pilling has plagued the textile industry for dozens of years. Controlling this problem begins with selecting raw materials with pill avoidance in mind. The next step in controlling pilling is to construct a yarn through the proper pill resistant steps. Finally, finishing and dyeing techniques can be adjusted to help reduce a fabric's pilling tendencies. It has been determined that as fiber denier becomes finer a fabric tends to pill more. Most published work done in this area was conducted on fibers coarser than 1.2 denier, therefore investigation was needed in this area. How polyester and cotton fibers are blended and its affects on pilling has not been investigated. An investigation of how these variables in combination with ring, rotor and air jet spinning systems affected pilling was the purpose of this thesis. Knit fabrics were constructed from 50/50 polyester/cotton yarns spun ort ring, rotor and air jet spinning systems. These fibers were intimately and draw frame blended. Three polyester fiber deniers were used: 0.85, 1.2 and 1.5. Additionally, fibers with a high and a low level of tenacity were used at each denier. Statistical analysis of the amount of time. required for a fabric to reach a pill rating of one revealed several results. The first, was that air jet yarns pill less than ring and rotor yarns. Ring yarns showed the least amount of resistance to pilling. Secondly, this work revealed that intimate blended yarns are less likely to pill than drawframe blended yarns. However, this did not hold true for ring spun yarns, where blending method made no difference in RTP pilling times. Another result of this thesis was that the 0.85 deniers pilled worse than the other two, but more so within the rotor spinning system then in the others. Regression analysis of fiber properties other than denier and tenacity revealed that other factors need to be considered where pilling is concerned. Flexural rigidity and fiber-to-fiber cohesion affected how air jet yarns pilled. Finish level affected how readily open-end yarns pilled.