Leather Extraction
International standardization protocols define test procedures for measuring the pH value and difference figure of aqueous leather extracts. Testing compliance under ISO 4045 evaluates the residual acid or alkali content in finished leather used for apparel, footwear and leather goods. Controlling extract pH prevents leather degradation, prevents hardware corrosion on finished garments and ensures user skin safety.
Difference Figure
Leather swatches are ground into uniform particles and shaken in distilled water for six hours at room temperature. A calibrated combined glass electrode measures extract pH, followed by a tenfold dilution step to calculate the difference figure that indicates strong acid presence.
Tannery Neutralization
Tanning and fatliquoring operations utilize acidic and basic chemicals that remain partially bound within the collagen fiber structure. Excess strong acids cause acid hydrolysis, embrittling leather fibers during storage and garment wear. Commercial buyers require certification under this standard to confirm that finished leather items meet international safety and durability thresholds.
Leather tanneries adjust final washing and neutralization cycles based on test results to maintain target pH levels between 3.5 and 7.0.
Matrix Scope
The standard applies specifically to leather materials and does not replace textile pH standards for woven or knitted fabric components. Non-leather trims, synthetic linings and metal hardware attached to leather goods require separate testing under applicable textile or chemical standards. Incomplete extraction due to coarse sample grinding yields falsely elevated or depressed pH readings.
