Overview
EN ISO 15701:2022 - Leather - Tests for colour fastness - Colour fastness to migration into polymeric material (ISO 15701:2022) specifies a laboratory method to assess the tendency of dyes and pigments to migrate from leather onto a synthetic (polymeric) substrate. The method measures colour transfer from a leather specimen to a white polymeric sheet when held in contact under defined heat and pressure. It applies to all types of leather at any stage of processing and is published as a CEN-adopted European Standard.
Key topics and technical requirements
- Test principle: A leather test specimen is placed face down on a white polymeric sheet to form a composite, then exposed to controlled heat and pressure to promote dye migration. Colour transfer is evaluated afterwards.
- Specimen size and materials: Typical leather specimen is (30 × 20) mm; polymeric sheet commonly used is pigmented white plasticized PVC ~0.5 ± 0.1 mm thick (other polymeric materials accepted).
- Apparatus & conditions:
- Test apparatus must apply a uniform pressure of (81.7 ± 4.0) kPa (approximately a 5 kg load) between inert plates (e.g., glass).
- Oven temperature: (50 ± 2) °C; load weight preheated for at least 2 hours.
- If required, the leather finish may be tested intact or with the finish intentionally broken (abrasion preparation described).
- Assessment:
- Degree of staining on the polymeric sheet is rated using the ISO grey scale for assessing staining (ISO 105-A03) or by an instrumental method conforming to ISO 105-A04.
- Precision and reporting: The standard defines specimen preparation, pressure/area considerations, and mandatory information to include in the test report (e.g., whether finish was broken).
Applications and users
- Practical applications:
- Quality control and pre-production screening to prevent unwanted dye transfer to synthetic components (linings, substrates, trim).
- Product compliance testing for footwear, upholstery, automotive leather, accessories and garments where leather contacts synthetic parts.
- R&D for leather dyeing/formulation optimization to reduce migration risk.
- Who uses it:
- Tanneries and leather finishers, material testing laboratories, product designers, footwear and upholstery manufacturers, and compliance/quality managers.
Related standards
- ISO 105-A03 - Grey scale for assessing staining (referenced for visual grading)
- ISO 105-A04 - Instrumental assessment of staining
- ISO 2418 - Leather sampling location
- ISO 105-A01 - General colour fastness principles (guidance)
Keywords: EN ISO 15701:2022, colour fastness, migration into polymeric material, leather testing, dye migration, leather quality control.