ISO 11640:2018

Overview

ISO 11640:2018 specifies a standardized method to assess colour fastness of leather to cycles of to-and-fro rubbing (the VESLIC rub test). The procedure measures both the staining of wool felt and the change in colour or surface of leather after controlled rubbing with wool felt. It applies to leathers of all kinds and is used to evaluate rub resistance in dry, wet or perspiration-conditioned states.

Key topics and technical requirements

• Principle: A leather specimen is rubbed with pieces of reference wool felt under a defined pressure and number of forward/backward cycles; results are assessed with grey scales (visual) or instrumentally.
• Apparatus essentials:
  • Carriage with flat platform and specimen holder; ability to extend leather (typically 10%).
  • Removable “finger” assembly: base 15 × 15 mm, cavity depth 3.9 mm, loaded to a total mass of 1 000 g ± 35 g (or 500 g ± 25 g for high-friction leathers).
  • Drive providing 35–40 mm travel at 40 cycles/min ± 2 cycles/min.
• Wool felt: square pieces ~15 × 15 mm from pure wool felt with mass per area 1 900 g/m² ± 150 g/m², thickness 6.0 mm ± 0.5 mm; black felt dyed with Acid Black 24 (or equivalent).
• Conditioning:
  • Dry conditioning per ISO 2419.
  • Wet felt and wet leather prepared using boiling or vacuum cycles (vacuum ~5 kPa) and limited soak times.
  • Felt wetted with artificial perspiration solution per ISO 11641 is also specified.
• Assessment:
  • Visual grading using ISO 105-A02 (change in colour) and ISO 105-A03 (staining).
  • Instrumental assessment allowed via spectrophotometer/colorimeter per ISO 105-A04/A05.
• Reporting: Include test conditions (extension, mass used, number of cycles, felt condition, use of shoe polish or brushing for finished/suede leathers) and any surface damage or pilling.

Applications and users

ISO 11640:2018 is practical for:

• Leather tanneries and finishers validating rub resistance of crust and finished leathers.
• Footwear, upholstery, garment and accessory manufacturers assessing end-use durability.
• Quality control labs, independent test houses and R&D teams comparing formulations, dyes and coatings.
• Compliance and product specification writing where leather testing, colour fastness and rubbing resistance are required.

Keywords: ISO 11640:2018, colour fastness, leather testing, VESLIC rub test, wool felt, rubbing test, grey scale assessment, wet conditioning.

Related standards

• ISO 105-A01, A02, A03, A04, A05 (colour fastness principles and grey scales)
• ISO 2418, ISO 2419 (sampling, conditioning)
• ISO 11641 (colour fastness to perspiration)
• ISO 3696, ISO 4045, ISO 9073-2, EN 15987