Type Approval against Lot Conformity on a Repeat Order
Type approval certificates prove mill capability, while targeted lot indicator testing on repeat orders verifies shipment conformity before vessel loading.
Fabric Surface Ph
Chemical Metric
Numerical scales measuring the acidity or alkalinity of processed textiles indicate the presence of chemical residues from wet treatment stages. The fabric surface ph of finished apparel is measured to ensure that garments do not cause skin irritation when worn. This metric must fall within a neutral range to satisfy safety standards.
Testing Procedure
Laboratory technicians determine this value by extracting a textile specimen in distilled water and measuring the resulting solution with a digital meter according to international test standards. High fabric surface ph values often result from inadequate rinsing of sodium hydroxide or other alkaline agents after scouring, mercerization or bleaching processes. Conversely, low values indicate the presence of residual acids from neutralizing baths that have not been thoroughly flushed out.
Skin Compatibility
Sensory evaluations show that human skin is mildly acidic and can react poorly to garments that are too alkaline. A high fabric surface ph can disrupt the natural protective barrier of the wearer’s skin, leading to dermatitis or redness, particularly in infants. Brands enforce strict limits to protect consumers from these reactions.
Process Control
Dyehouses manage this property by adding neutralizing agents like acetic acid during the final wash cycle of the finishing process. Consistent monitoring on the production floor prevents the shipment of alkaline fabric lots. This control protects both the fabric hand and consumer safety.