Can sodium sulfate be substituted at equal weight?
Electrolyte composition and addition timing affect the dye bath. Neither commercial weight nor final depth describes the whole exhaustion process.
Track the fabric after each salt addition
Use the same fabric and dye, retain the existing recipe as a control and record salt additions, bath state and swatches over time. Focus on rapid uptake and color difference after washing.
Why does shade differ at the same salt dose?
Check salt impurities, water hardness and the salt addition profile in addition to main salt assay. Reactive dyeing of cellulose: Run a salt concentration series with the same fabric and dye. Salt dissolution and recirculation: Measure dissolution, filter residue and holding-tank deposits.
Checking Sodium chloride assay and Calcium and magnesium impurities
Sodium chloride assay (% by mass): State dry or as-received basis. Calcium and magnesium impurities (mg/kg): State whether the result is an individual concentration or a hardness equivalent. Water-insoluble matter (% by mass): Keep sample mass, water temperature and filter material constant.
What to record
- Salt type
- Salt basis
- Salt per addition
- Dye uptake time points
- Color difference after washing
Technical references
Products and processes
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