Investigation of fiber maturity effect on saw-type lint cleaner fiber damage and yarn properties

Authors: Byler, Richard; Delhom, Chris; Sassenrath, Gretchen; KRIFA, MOURAD - University Of Texas

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/19/2011
Publication Date: 6/1/2011
Citation: Byler, R.K., Delhom, C.D., Sassenrath, G.F., Krifa, M. 2011. Investigation of fiber maturity effect on saw-type lint cleaner fiber damage and yarn properties. Proceedings of Beltwide Cotton Prod. Res. Conf., Jan 5-7, 2011, Atlanta, GA. p. 659-667.

Interpretive Summary: Examination of mill processing of cotton has shown that immature cotton fibers are weaker and more easily damaged than mature cotton fibers. All cotton gins using saw-type gin stands also employ saw-type lint cleaners because they are efficient cleaners. These lint cleaners have been shown to damage the lint but the damage which has been observed varies considerably. The effect fiber maturity has on cotton fiber cleaning in the cotton gin has not been investigated or documented adequately. For this work two cotton cultivars were grown in replicated plots and half of each plot was defoliated earlier than the other half to create immature and mature cotton lots which were otherwise very similar. These lots of cotton were ginned with four ginning processes from very gentle to somewhat rigorous. These cotton lots were then processed in a small scale mill and spun into yarn. Fiber and yarn samples were tested for each cotton lot and the data analyzed statistically. The early and later defoliation resulted in cotton lots with different maturities. The less mature cottons were more easily damaged during lint cleaning at the gin than the more mature cottons. The immature cotton processed gently at the gin (with no lint cleaner) was longer than the mature fiber processed normally at the gin, but after mill processing the fiber length was lower for the gently processed less mature cotton than for any of the mature cottons. The bale samples of the mature cotton well represented the fiber quality after mill processing but the bale samples of the immature cotton were considerably better than the fiber after mill processing. For the immature cotton, the bale samples after normal gin processing were more representative of the cotton after mill processing than the samples after especially gentile lint cleaning. This data showed that for mature cotton the lint cleaners do some damage to the fiber, but the subsequent mill processing does very little additional damage. However, for the immature cotton, the gin processing does more damage than for the mature cotton and the mill processing does additional damage. This study shows that improvements in lint cleaner design may benefit the cotton producers but make the marketing of cotton fiber more complicated because the official cotton class would be less reliable in predicting the value of the fiber for producing yarn.

Technical Abstract: One-half of plots of two cotton cultivars with similar mature fiber length were harvested after two defoliation treatments (early/late) to get less and more mature cottons. These seed cotton lots were ginned with the same seed cotton cleaning but with 0, 1, or 3 saw-type lint cleaners with low drying heat or 1 lint cleaner with moderate drying heat. Each of these cottons was then processed and 22 Ne yarn spun in a mini-spinning process. Samples of these fibers and yarns were tested. The early defoliation resulted in differences in fiber maturity but the micronaire range was not large. The cottons defoliated early were shorter, weaker, with more short fiber. The gin processes affected the AFIS fiber length but not the short fiber content. The cottons defoliated early decreased in fiber length during gin and mill processing more than those defoliated later. The early defoliated cotton, which was less mature, lost length and gained short fiber more during mill processing than the more mature cotton. The immature cotton processed gently at the gin (with no lint cleaner) was as long as the mature fiber processed normally at the gin, but after mill processing the fiber length was lower for the gently processed less mature cotton than for any of the mature cottons. These differences seen with AFIS measurements were less obvious in the yarn, but the skein strength and yarn neps were of lower quality for the less mature cottons.