Thesis Details

Thesis Title: Evaluation of the effects of lubrication on size film formation consistency by utilization of a dynamic tensile test
Thesis Author: James Zeiba
Abstract: The formation of an adequate size coating on yarn is necessary to prevent abrasion and clinging of the yarn during weaving. Although the size film aids the yarn against abrasion and clinging, it has a tendency to adversely affect the yarn elongation, therefore some have assumed a lubricant is necessary. Much speculation has occurred about the effects of lubricant to size film formation on yarns, but few extensive studies have been performed. Howard Thomas has found that it is possible to use a derivative tensile test to evaluate the consistency (fragmentation) of the size film formation on ring spun yarn, and to relate the results to Sulzer-Ruti Webtester results. His research indicated that ring spun yarns having fragmented size film appeared similar to an unsized yarn's stress-strain curve derivatives. Whereas Thomas' research demonstrated a relationship for ring spun yarn, it was not known if such a relationship existed in the other yarn formation systems. This thesis investigated if such a relationship existed in open-end, air jet, and textured filament yarns, and if it can be evaluated by a dynamic tensile test. The investigative results of this research are as follows: 1. In all yarn types, lubricants were found to adversely affect the performance of the yarn as compared to non-lubricated samples. This was based on the following tests: " Sulzer Ruti Webtester - Abrasion Resistance " Tensile and Elongation Analysis - Instron " Analysis of Force-Load Derivatives - Instron From the results of this testing it was determined that an oil based lubricant was more damaging to staple fiber yarn than a wax lubricant. It was also shown that an increased concentration of lubricant increases the severity of the its affect, based on the levels used in this study. 2. By use of coefficient of fragmentation and derivative analysis it was determined that all yarn types exhibit similar size film degradation and fragmentation results as observed by Thomasam. This is to say that sized, lubricated yarns respond more like unsized yarn than a sized non-lubricated yarn. This result indicates the lubricant is hampering the proper size film formation on the yarn structure. The third specific objective of comparing the effects of lubricant applied in-bath to lubricant applied after the bath yielded the following conclusions: 3. For all yarns, the wax and oil in-bath lubrication was more detrimental to size film than after the bath lubrication. It was also determined that oil lubricant was more damaging than wax lubricant when used as an after lubrication. Regression analysis was used to determine the relationship between the Webtester results and the derivative analysis. Ninety-four percent of the variation to be explained by utilizing the equation: Webtester ST-6 = -3121.874 + 10.199(SE strength) + 4.192(Sum of 1st Derivative of Load) [6]