The transition stages in textile dyeing and leather tanning rely heavily on precise pH adjustments. Acetates are preferred over strong mineral acids or harsh alkalis because they provide a gentle, non-destructive pH gradient.
Leather processing
After the unhairing stage, which is highly alkaline, hides must be delimed. Sodium acetate and sodium diacetate act as effective deliming agents.
They gently neutralize the lime without lowering the pH excessively, thereby preventing acid swelling of the collagen fibers. They can also be used in combination with formic acid.
During chrome tanning, sodium acetate functions as a basifying agent, gradually increasing the pH to promote the fixation of chromium complexes to the collagen matrix.
Textile dyeing
In textile processing, particularly when dyeing synthetic fibers or wool with acid dyes, sodium acetate acts as a leveling agent.
By buffering the dye bath, it controls the dye uptake rate, ensuring uniform, streak-free colour distribution.
Discharge printing
Sodium acetate neutralizes residual acids in discharge printing pastes, helping to protect the tensile strength of cotton and silk fibers.
