ISO 17233:2017

Overview

ISO 17233:2017 - Leather - Physical and mechanical tests - Determination of cold crack temperature of surface coatings defines a standardized laboratory method to determine the cold crack temperature of surface coatings applied to leather. The method is applicable to all coated leather types that can be easily flexed and is intended for use in quality control, specification compliance and product development where low-temperature coating performance matters.

Key topics and requirements

• Scope: Test applies to leathers with a surface coating and that are easily flexed. It does not apply to rigid materials.
• Principle: A leather strip is flexed in a hinged holder inside a cooled chamber and inspected for coating cracks after controlled cold exposure.
• Apparatus:
  • Cooled chamber capable of maintaining +5 °C to −30 °C with temperature control to ±2 °C (minimum internal dimensions specified).
  • Hinged sample holder sized to hold at least six test pieces without contact; marks for adhesive-tape fixation allowed.
  • Press knife to cut rectangular test pieces of (90 ± 1) mm × (10 ± 1) mm.
  • Magnifier (4–6×) and temperature measuring device (readable to 1 °C).
  • Adhesive tape suitable to −30 °C (optional method of fixing).
• Sampling & preparation:
  • Follow ISO 2418 and ISO 2419 for sampling, cutting and conditioning.
  • For each tested temperature use six test pieces: three cut parallel and three perpendicular to backbone (or two sets at right angles if backbone unknown).
  • Optional 5 mm holes near ends if fixing with bolts; holes not required when using adhesive tape.
• Procedure:
  • Condition holder and samples at test temperature, rapidly snap the holder closed to flex coating outwards, return to room temperature and inspect for cracks with magnifier.
  • Test sequence typically starts at +5 °C and proceeds through 0, −5, −10, −15, −20, −25 and −30 °C using fresh sets until at least two test pieces crack.
• Acceptance & reporting:
  • Record the highest temperature at which at least two of the six pieces show cracking.
  • If no cracking at −30 °C report <(−30 ± 2) °C.
  • Test report must reference ISO 17233:2017 and include observed cracking, deviations and sample identification.

Applications and users

• Quality control laboratories in tanneries and finishing plants
• Coating formulators and R&D teams developing leather finishes
• Footwear, automotive, furniture and apparel manufacturers specifying low-temperature performance
• Supplier verification and compliance testing for product specifications and procurement

Related standards

• ISO 2418 - Sampling location for leather
• ISO 2419 - Sample preparation and conditioning for leather tests
• EN 15987 - Leather terminology and definitions

Keywords: ISO 17233, cold crack temperature, leather testing, surface coatings, coated leather, cooled chamber, hinged sample holder.