Overview
SIST EN ISO 20701:2024 is an international standard developed by CEN and IULTCS that specifies a standardized test method for assessing the colour fastness of leather to saliva. This test is crucial for determining whether dyes or colouring agents used in leather products can migrate when exposed to saliva. The method employs an artificial saliva solution to simulate real-life exposure, ensuring that leather used in products such as footwear, gloves, and other items in contact with the mouth or mucous membranes is safe and maintains its colour integrity.
Key Topics
- Scope: Applies to all types of leather regardless of the colouring procedure used, ensuring broad applicability across the leather industry.
- Test Principle: A filter paper soaked in artificial saliva is placed in contact with the leather sample at 37 ± 2 °C for 120 ± 5 minutes. The assessment involves visual evaluation of colour change on the leather and staining on the filter paper using grey scale methods.
- Artificial Saliva Composition: The artificial saliva solution is carefully formulated using specific salts such as magnesium chloride, calcium chloride, potassium phosphate, and others to mimic the chemical environment of human saliva with a pH of 6.8 ± 0.1.
- Materials and Equipment: Includes filter paper, adhesive tape, desiccator, oven, pH meter, and standard grey scales for staining and colour change rating, enabling consistent and reproducible results.
- Standardized Procedure: Detailed steps cover specimen preparation, filter paper application, incubation conditions, drying procedures, and evaluation criteria to ensure consistency in testing across laboratories.
- Reference to Related ISO Standards: The standard aligns with ISO 7906 for general colour fastness principles, ISO 2418 for specimen preparation, and ISO 105 series for grey scale assessments, ensuring harmonized methodologies.
Applications
- Leather Quality Control: Manufacturers use this test to verify the durability and safety of dyed leather in products that may come into contact with saliva, such as gloves, footwear linings, upholstery, and wearable accessories.
- Consumer Safety: Ensures that toxic or harmful dyes do not leach from leather to the mouth, protecting consumers from potential health risks.
- Compliance and Certification: Helps tanneries and product designers meet national and international regulations on material safety and product quality, facilitating market access globally.
- R&D for Leather Treatments: Enables research into improved dye fixation techniques and finishes that enhance resistance to colour migration under realistic exposure conditions.
Related Standards
- ISO 7906 – Leather tests for colour fastness: general principles of testing, providing foundational methodologies.
- ISO 2418 – Leather: chemical, physical, mechanical, and fastness tests specimen preparation and positioning.
- ISO 105-A02 & ISO 105-A03 – Grey scales for assessing colour change and staining essential for interpreting the test results accurately.
- ISO 3696 – Specifies the quality of water used in test solutions to maintain reproducibility and accuracy.
- EN 15987 & ISO 15115 – Define leather terminology relevant to the testing processes for common understanding.
SIST EN ISO 20701:2024 plays a vital role in leather product development and quality assurance by providing a reliable method to ensure colour fastness to saliva, emphasizing consumer safety and product durability. Its wide recognition and harmonization with other international standards make it a cornerstone for professionals involved in leather testing, certification, and manufacturing industries.