Statistical Variable Acceptance Plans for Transverse Chemical Skew in Wet Processing
Variable acceptance plans under ISO 3951-1 quantify transverse wet-processing skew through across-width chemical assay data, preventing border detentions.
Extraction Titration
Chemical Analysis
A laboratory separation technique combines solvent extraction with volumetric analysis to measure the concentration of specific chemical compounds in a textile substrate. In fabric manufacturing, extraction titration determines the amount of residual oils, spinning lubricants or sizing agents remaining on the yarn after scouring. It ensures that the fabric is clean enough to accept dyes and finishes evenly.
Methodological Steps
The procedure begins by exposing a weighed fabric sample to a selective solvent that dissolves the target residue and leaves the underlying fiber unaffected. This solvent phase is then separated from the solid textile material. The extracted solute is subsequently reacted with a standardized titrant solution of known concentration until the chemical reaction reaches its stoichiometric endpoint.
An indicator chemical or a pH electrode monitors this endpoint to signal that the titration is complete.
Detergency Measurement
Calculating the volume of titrant consumed during the reaction translates to the mass of the residue extracted from the textile. If the amount of spinning oil on the fabric exceeds the specified limit, it can block dye molecules and lead to patchy coloration. This dual-stage test provides a quantitative verification of wash efficiency before the material enters the dye jet.
Analytical Boundary
This analytical approach is limited to residues that can be completely dissolved by the selected solvent. If the solvent also dissolves some of the textile fiber itself, the results will be falsely high. Therefore, selecting the correct solvent represents the most critical step in configuring this test for different fiber types.