Thesis Details

Thesis Title: The relationships between fiber properties, spinlab rotorring cohesion measurements, and open-end rotor spun yarn qualities using 100 percent acrylic fibers
Thesis Author: Gary W. Moore, Jr.
Abstract: Because it is a function of several fiber properties, fiber cohesion is an important factor in the manufacturing of staple yarns. Much research has been done in the attempt to characterize the cohesive properties of various fibers and relate these properties to yarn properties and processability. If these relationships are known, they might be used to better control fiber performance in the yarn manufacturing process. The primary obstacle in the study and characterization of fiber cohesion has been the method used to measure the property itself. The spinlab Rotorring provides the user with a quick and easy method of characterizing fiber cohesion. However, the major advantage of the Rotorring is its ability to characterize the cohesion of raw stock. Acrylic fibers were manufactured using two different finish types, finish levels, stretch types, and antistat levels. These fibers were then processed into 21/1 open-end rotor spun cotton count yarns. In studying the effect of fiber properties on Rotorring cohesion, the fiber cohesion increased with increasing crimp, decreasing crimp amplitude, denier, percent finish, and percent extractables. Although some of the relationships were relatively poor, several were excellent and illustrated the Rotorring’s ability to detect changes and their effect on cohesion. without a doubt, the type of finish was the determining factor in the cohesion of the acrylic fiber, with anionic finishes providing much higher fiber cohesion. In studying the relationships between RotorRing cohesion and yarn properties and processing performance, most yarn properties correlated with at least one of the three RotorRing measurements. The relationships were especially strong for single-end strength, single-end elongation, break factor, and Uster CV. The relationships were not as strong for "imperfections," such as Uster and Classimat imperfections but were still acceptable and statistically significant. The reason for the poorer correlation was because of the relatively "loose" fit provided by these measurements at lower cohesion values. This seems to indicate that the "chance" for imperfections is greater at lower fiber cohesion levels. For this acrylic yarn and the cohesion range it occupies, the overall yarn quality and processability was superior at higher levels of fiber cohesion. The results of this thesis will allow the yarn manufacturer to establish his “optimum” cohesion range and to detect any lots exhibiting abnormal cohesion from that needed for processing. The relationships between fiber properties and yarn quality will provide the yarn manufacturer with the information needed to work with the fiber manufacturer in the creation of a superior product.