SIST EN ISO 17236:2025

SIST EN ISO 17236:2025 – Leather: Physical and mechanical tests – Determination of extension set specifies a standardized laboratory method to evaluate the permanent deformation (extension set) of leather after cyclic tensile loading. This method is applicable to all flexible leathers, particularly upholstery leather, and provides reproducible data for quality control, R&D, and compliance testing.

Scope and Purpose

Measures leather’s permanent deformation after repeated stretching.

Supports durability assessment for upholstery, footwear, leather goods, and other applications requiring mechanical reliability.

Test Principle

Leather specimens are cyclically extended to a set force level.

Load is held for a defined time, then removed.

Residual elongation is measured and expressed as a percentage of the initial gauge length.

Specimen Preparation and Conditioning

Cut test specimens per ISO 2418.

Condition specimens under standard atmospheres per ISO 2419.

Measure thickness using ISO 2589 to ensure uniformity.

Apparatus

Tensile testing machine calibrated per ISO 7500-1.

Jaws to prevent slippage during cyclic loading.

Press knife for precise specimen cutting.

Ruler and thickness gauge for measurements.

Stopwatch for timing load cycles.

Test Procedure

Mark parallel lines on specimens to gauge elongation.

Apply five tensile load cycles to 20 N ± 0.5 N.

Hold load for 10 seconds during each cycle.

Measure residual extension after 60 seconds post-test.

Calculate extension set (%) using the standardized formula.

Results and Reporting

Include specimen identification, conditioning parameters, pre-load values, average extension set, specimen thickness, deviations, and test date.

Applications and Users

Upholstery Leather Quality Control: Ensure dimensional stability under mechanical stress.

Footwear and Leather Goods Testing: Predict product performance during wear and handling.

Research and Development: Guide formulation adjustments and material innovation.

Regulatory Compliance and Certification: Provide standardized data for customer and regulatory requirements.

Related Standards

ISO 2418 – Specimen preparation and positioning.

ISO 2419 – Conditioning and testing environments.

ISO 2589 – Thickness measurement of leather.

ISO 7500-1 – Calibration and verification of tensile testing machines.

Qinsun Instruments is a professional instrument equipment manufacturer, providing one-stop solutions for leather testing and laboratory needs.

2026-01-07 18:13