Acidity Measurement
A standardized test method determines the acidity or alkalinity of an aqueous extract prepared from textile materials. Quality assurance laboratories perform the ISO 3071 extract ph test to ensure that finished apparel does not cause skin irritation to the consumer. This standard extraction uses distilled water or a potassium chloride solution to draw out acid or alkali residues from the processed fabric.
By measuring the chemical balance of the extract, the mill ensures that the textile holds no active processing residues.
Testing Sequence
Technicians mix the textile specimen with the liquid extractant and agitate it for two hours. Measuring the pH of the resulting solution using a calibrated glass electrode yields the extraction value. This value must fall within a safe range to pass retail compliance.
Dyehouse Verification
Excess chemical residues from bleaching or dyeing can remain on fabric if scouring is inadequate. Testing after the final wash cycle verifies that the chemical neutralization steps were successful. This check prevents the distribution of fabrics with incorrect acidity.
Compliance Standard
Retail brands require finished fabrics to maintain a near-neutral extraction value. If the fabric fails this test, the manufacturer must repeat the scouring and rinsing process. This additional wash step increases production costs but guarantees chemical safety.
