A Study of Bale Moisture Addition

The study of the addition of water to cotton at ginning dates back to the early 1950s. Since that time, technologies have changed, allowing for more control and higher volumes of water to be added to cotton at the lint slide than ever before. The objective of this study was to determine an acceptable bale moisture range within which fiber quality, yarn quality, and dyed fabric quality degradation can safely be avoided after six months of bale storage. Approximately 22.7 kg (50 lbs) of cotton were sampled from each of the three bales for each of the four moisture treatments after six months in storage. In addition to the HVI fiber properties, additional testing of the fibers was performed on the Advanced Fiber Information System (AFIS), as well as a microbial assay to determine any microbial damage to the cotton during storage. The resulting 20/1 open-end spun yarns were subjected to typical yarn quality measurements (C.V., defects, strength, and elongation) and then circular-knit into panels so that yarn from each treatment was butt-knit to more easily observe color or shade change. HVI data indicated that the moisture treatment levels and storage period had an adverse impact on color Rd and +b with increasing amounts of water added at the lint slide. Although microbial data were collected, the data did not indicate any significant activity during the six months of storage. As for yarn quality, it appears that 9.1 kg (20 lbs) or more of water added to bales of cotton at the lint slide resulted in significant as well as practical reductions in yarn quality. With respect to the six-month storage period and the treatments used in this study, although there were color changes to the cotton fiber, there appeared to be no impact on the bleached and dyed fabric. Additionally, it appears that the point of diminishing return for adding moisture to cotton at the lint slide lies between 6% and 8.5%.