Effect of Cotton Stickiness on Yarn Production Process: A Comprehensive Statistical and Process Study

Cotton stickiness, arising primarily from insect-derived honeydew sugars and physiological plant sugars, constitutes one of the most challenging quality variables in modern yarn manufacturing. Despite advances in High Volume Instrument (HVI) fibre characterisation, the unpredictable spatial distribution of sugar content across cotton bales makes stickiness difficult to control at the raw material procurement stage. This study presents a comprehensive experimental and statistical investigation into the mechanisms by which stickiness — quantified via the Contest-S device following the UNI EN 278-3 standard — propagates through the ring-spinning process to affect yarn quality, machinery performance, and cot lapping behaviour.

Three cotton blends (X, Y, Z) with mean stickiness grades of 201.50 (High), 128.15 (Medium), and 94.10 (Low) respectively were used to produce 12 variants of Ne 32/1 combed compact yarn under a 2×2 factorial design incorporating UV cot surface treatment and two distinct climate-conditioning regimes (36°C/46% RH and 32°C/52% RH). Yarn quality was evaluated using the Uster tester, and lapping tendency was tracked on both spinning and preparatory cots over standardised production intervals.

Regression analysis revealed statistically significant relationships (p < 0.05) between stickiness grade and key yarn quality parameters including unevenness (R² = 62%), Cvm (R² = 66%), neps +200% (R² = 81%), breaking force (R² = 76%), and RKM (R² = 74%). Stickiness grade was also highly predictable from fibre properties using a multivariate regression model incorporating Micronaire, elongation, fibre strength, and reflectance, achieving R² = 99%. Tukey post-hoc analysis indicated significant differences in preparatory cot lapping between high- and low-stickiness blends (p < 0.05), whereas UV treatment and climate conditioning were found to have no statistically significant independent effect on lapping tendency. These findings confirm that stickiness grade — rather than ambient processing conditions — is the primary driver of quality degradation and machine downtime in ring spinning.