Alkalinity Control
Controlled addition of a strong caustic solution to a wet processing bath is used to manage the chemical environment for dyeing or finishing. In a cotton mill, sodium hydroxide dosing is the primary method for adjusting the pH to the level required for the fixation of reactive dyes. The liquid is added in stages to prevent a sudden spike in alkalinity.
This process stops when the target pH value is reached and stabilized.
Mercerization Process
Treatment of cotton yarn with high concentrations of caustic soda improves its luster and strength. Precise sodium hydroxide dosing during mercerization ensures that the fibers swell uniformly and the tension is maintained. This leads to a fabric that has a better affinity for dyes and a smoother surface.
pH Management
Stability of the chemical reactions depends on the ability of the system to maintain a constant level of hydroxide ions. When sodium hydroxide dosing is inaccurate, the color of the fabric will be uneven and the mechanical properties may be compromised. Automated sensors provide the data needed to regulate the pump speed.
Fabric Strength
Excessive exposure to strong alkalis can damage the cellulose chains and weaken the material. Sodium hydroxide dosing must be carefully monitored to ensure that the caustic is neutralized or washed away immediately after the reaction. It is a critical checkpoint for the quality control of the finishing line.
