Overview
ISO 3380:2015 - Leather - Physical and mechanical tests - Determination of shrinkage temperature up to 100 °C - specifies a standardized laboratory method to determine the shrinkage temperature of leather (up to 100 °C). Prepared by IULTCS in cooperation with CEN, the method is applicable to all leathers and is used to assess thermal stability related to collagen denaturation.
Key topics and technical requirements
- Scope: Determination of the temperature at which a leather specimen undergoes sudden shrinkage when heated in water (up to 100 °C).
- Principle: Heat a suspended test piece in water at a controlled rate and record the temperature at which a measurable shrinkage occurs.
- Apparatus essentials:
- Vessel (≥ 500 ml, working depth ≥ 110 mm) and heater capable of a controlled heating rate.
- Fixed and moveable test-piece holders, pulley and pointer system with at least 5× magnification of movement.
- Temperature sensor accurate to ±0.5 °C, graduated to 1 °C.
- Stirrer to keep temperature uniform (top-to-bottom difference ≤ 1 °C).
- Optional pressurized vessel for testing above 100 °C.
- Sample preparation:
- Sampling per ISO 2418; thickness measured per ISO 2589.
- Test-piece dimensions: typically 50 mm × 3.0 mm (≤ 3 mm thick) or 50 mm × 2.0 mm (> 3 mm thick); orientation: two samples parallel and two perpendicular to backbone.
- Procedure highlights:
- For dry samples: pre-immerse in 5.5 ml water in a sealed tube, evacuate desiccator to