Overview
ISO 7979:2025 - Leather - Tests for colour fastness - Colour fastness to hydroalcoholic mixtures is a new international test method (first edition, 2025) developed by IULTCS in cooperation with CEN. The standard defines controlled laboratory methods to assess the colour fastness of leather surfaces when exposed to hydroalcoholic mixtures (alcohol + water formulations), reflecting real‑world exposure such as disinfectants, sanitizers and cleaning products.
Key topics and technical requirements
- Scope: Applicable to all kinds of leather; evaluates surface fastness to hydroalcoholic mixtures.
- Test principle: Two complementary approaches:
- Method 1 - Surface wetting: a cotton cloth (≈50 × 50 mm) is wetted with (0.5 ± 0.1) ml of test medium, covered by a Petri dish and aged in a heating cabinet (standard: 40 °C ± 2 °C for 2 ± 0.25 h; optional 60 °C).
- Method 2 - Linear rubbing: a wool felt or cotton cloth soaked with (0.5 ± 0.1) ml test medium is rubbed against the leather for defined cycles (Procedure A follows ISO 11640; Procedure B follows ISO 20433).
- Test media: Standard formulations are specified, e.g. Test medium A - 70% ethanol (v/v); Test medium B - water/ethanol/2‑propanol/benzalkonium chloride/glycerine mixture; Test medium C - agreed composition.
- Specimen conditioning and cleanup: Preconditioning per ISO 2419; post‑test cleaning procedure; reconditioning for at least 16 h at 23 ± 2 °C and 50 ± 5% RH before evaluation.
- Evaluation: Visual and, if needed, instrumental assessment against untreated reference areas using grey scales (ISO 105‑A02, ISO 105‑A03). Annex provides a visual evaluation scheme.
- Equipment and consumables: Pipettes (±0.1 ml), Petri dishes, glass plates, wool felt, ISO‑specified cotton rubbing cloth, heating cabinet with air circulation, specified chemicals (ethanol, 2‑propanol, benzalkonium chloride, glycerine).
Practical applications and users
- Who uses it: Leather manufacturers, tanneries, footwear and upholstery producers, quality control and testing laboratories, material specifiers, and product development teams.
- Why it matters: Ensures leather products retain appearance and resist staining, bronzing or colour transfer when exposed to sanitizers, hand‑sanitizer spills, cleaning agents and similar hydroalcoholic formulations. Useful for product claims, supplier agreements and regulatory compliance in markets demanding standardized fastness data.
Related standards
Key referenced documents for method details and evaluation:
Keywords: ISO 7979:2025, leather colour fastness, hydroalcoholic mixtures, leather testing, colour fastness test, IULTCS, leather quality control.
