Standardized Acceptance Thresholds for Starch Degradation and Peroxide Demand in Aged Cotton
Staged titration of residual active oxygen and TEGEWA violet scale ratings above six prevent catalytic fiber tenderization in aged cotton prep.
Pad-Steam Preparation
Continuous Treatment
Continuous wet processing of open-width woven fabrics allows for rapid chemical impregnation followed by immediate thermal activation. Utilizing pad-steam preparation, textile mills combine scouring and bleaching into a highly efficient sequence that handles thousands of meters of fabric per hour. This method ensures that chemicals are distributed evenly across the fabric face and back before exposure to saturated steam.
Process Sequence
Treatment begins as the fabric passes first through an applicator trough containing a solution of sodium hydroxide, hydrogen peroxide, and stabilizers. Squeeze rollers then remove excess liquid to achieve a precise wet pickup before the fabric enters the steaming chamber. The steaming action heats the fabric rapidly, driving the chemical reactions that remove natural impurities and whiten the fibres.
Production Output
Uniformity of the prepared cloth is critical for ensuring consistent dye absorption during subsequent coloration stages. Poorly prepared fabric results in listing or ending, where the color varies from the edge to the center or from the beginning to the end of a production run. Because the steaming chamber maintains a constant moisture and temperature profile, the resulting fabric exhibits excellent wettability and high whiteness.
This high level of consistency reduces the need for correction or re-dyeing, lowering the overall energy and chemical consumption of the dye house. Mill operators regularly inspect the steam pressure and chemical concentrations to ensure the system runs within narrow tolerance limits.
Process Limitation
Fabric structure dictates whether this continuous method is suitable, as heavy or highly twisted yarns require longer dwell times than the chamber can provide. Knit fabrics also present challenges due to their tendency to curl at the edges under tension. Therefore, the method is primarily reserved for flat woven fabrics made from cotton or cotton blends.