SIST EN ISO 17236:2025

SIST EN ISO 17236:2025 specifies a standardized method to measure the extension set (permanent deformation) of leather after cyclic tensile loading. Applicable to flexible leathers, it ensures consistent and repeatable evaluation for quality control, R&D, and compliance testing, especially for upholstery leather.

Scope and Purpose

(1) Determines permanent deformation (extension set) after repeated tensile stress.

(2) Evaluates leather durability and mechanical performance for end-use applications.

Testing Principle

(1) Cyclically extend leather specimens to a defined force.

(2) Hold the leather under load, then measure residual extension after unloading.

(3) Express extension set as a percentage of the initial gauge length.

Specimen Preparation and Conditioning

(1) Cut specimens following ISO 2418 guidelines.

(2) Condition specimens per ISO 2419 standard atmospheres.

(3) Measure specimen thickness using ISO 2589 procedures for uniformity.

Apparatus Requirements

(1) Tensile testing machine calibrated to ISO 7500-1.

(2) Jaws preventing specimen slippage.

(3) Press knife for accurate specimen cutting.

(4) Ruler and thickness gauge for measurements.

(5) Stopwatch for timing tensile cycles.

Test Procedure

(1) Mark specimens with parallel lines to gauge elongation.

(2) Apply five tensile load cycles of 20 N ± 0.5 N.

(3) Maintain load for 10 seconds per cycle.

(4) Measure extension after 60 seconds post-testing.

(5) Calculate extension set percentage using the defined formula.

Results and Reporting

(1) Report specimen identification and thickness.

(2) Include environmental conditioning parameters.

(3) Record pre-load values and average extension set.

(4) Note deviations from the standard and test date.

Applications

(1) Upholstery leather quality control to ensure dimensional stability.

(2) Footwear and leather goods testing to predict performance under stress.

(3) R&D for material development and formulation improvement.

(4) Regulatory compliance and certification of leather mechanical properties.

Related Standards

(1) ISO 2418 - Leather: Specimen preparation and positioning.

(2) ISO 2419 - Conditioning and testing environments of leather specimens.

(3) ISO 2589 - Leather: Methods for measuring leather thickness.

(4) ISO 7500-1 - Calibration and verification of tensile testing machines.

Following SIST EN ISO 17236:2025 ensures reliable, standardized measurement of leather extension set, supporting product quality, durability evaluation, and R&D development.

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2026-01-07 18:19