ISO 5431:2022 PDF

Overview - ISO 5431:2022 (Leather - Wet blue goat skins - Specification)

ISO 5431:2022 defines requirements, sampling and test methods for wet blue goat skins tanned without hair using basic chromium sulfate as the primary tanning agent. The third edition (2022) updates chemical requirements and adds tests such as determination of matter soluble in dichloromethane and chromic oxide content. This standard ensures consistent quality, safety and traceability for wet blue goat leather in commerce and manufacturing.

Key topics and technical requirements

• Raw material & tanning
  • Wet blue goat skins processed from cured or fresh goat skins.
  • Tanning with basic chromium sulfate; visual bluish penetration of the cut cross-section.
  • Tanning pH: 3.0 or above.
• Physical and appearance
  • Grain side free from hair (including short/fine hair); well fleshed; tight grain preferred.
  • At least 95% of skins in a lot should be free from chromium-salt stains; stained area per piece ≤ 10%.
  • Free from creases, drum folds and iron-salt stains.
• Thermal and chemical limits
  • Shrinkage temperature ≥ 95 °C (ISO 3380).
  • Volatile matter > 50% of dry mass (or as agreed).
  • **Matter soluble in dichloromethane