ISO 3377-2:2025 – Leather Double Edge Tear Test & Apparatus

ISO 3377-2:2025 – Leather: Physical and mechanical tests – Part 2: Determination of double edge tear load defines a standardized laboratory method for measuring the tear strength of leather using a double-edge (Baumann) tear. Applicable to all types of leather, this third-edition ISO/IULTCS method specifies specimen preparation, equipment, test procedure, and reporting, ensuring reproducible and comparable results across laboratories and supply chains.

Key Topics and Technical Requirements

Test Principle:

A rectangular test piece with a specified hole is torn between the turned-up ends of two holders in a tensile testing machine. The maximum force during tearing is recorded.

Apparatus:

(1) Tensile testing machine with a force measurement accuracy of at least ±2% (Class 2 per ISO 7500-1) and jaw separation speed of 100 mm/min ±20 mm/min.

(2) Steel test piece holders and press knife capable of cutting specimens in a single operation (per ISO 2418).

(3) Thickness gauge as specified in ISO 2589.

Sampling & Specimen Preparation:

(1) Cut six test pieces from each leather sample: three with the long side parallel to the backbone, three perpendicular.

(2) Condition specimens according to ISO 2419 before testing.

(3) Measure thickness at the prescribed location and use the mean value for strength calculations.

Procedure & Calculations:

(1) Mount the specimen on holders and perform the tear test using the tensile machine.

(2) Record the maximum force for each specimen.

(3) Calculate the mean tear load (N) from three specimens per orientation.

(4) Optional: calculate mean tear strength (N/mm) by dividing mean tear load by mean thickness.

Reporting Requirements:

(1) Reference ISO 3377-2:2025.

(2) Include mean thickness, mean tear loads (parallel and perpendicular to backbone), overall mean, optional N/mm strength, conditioning atmosphere, deviations, test date, and sample identification.

Applications and Users

ISO 3377-2:2025 is primarily used by:

(1) Leather tanneries and quality control laboratories to verify tear resistance.

(2) Footwear, upholstery, automotive, and leather-goods manufacturers for material selection and specification compliance.

(3) R&D teams evaluating processing, finishes, or treatments that affect tear strength.

(4) Certification bodies and procurement teams requiring reproducible tear strength data for supplier acceptance.

Practical Benefits:

Reliable comparison of leather grades.

Informed material selection for end-use performance.

Consistent and standardized test reporting for supply-chain communication.

Related Standards

(1) ISO 2418 – Specimen cutting and positioning

(2) ISO 2419 – Conditioning of leather specimens

(3) ISO 2589 – Thickness measurement

(4) ISO 7500-1 – Calibration/verification of tensile machines

(5) Other parts of the ISO 3377 series and IULTCS/IUP 8 methods

Recommended Testing Instruments

(1) Universal Tensile Testing Machine – With programmable speed, load cell accuracy ±2%, suitable for tensile and tear tests.

(2) Baumann Tear Holders – Steel holders with bent ends to support double-edge tear specimens.

(3) Press Knife – For precise specimen cutting per ISO 2418.

(4) Digital Thickness Gauge – For accurate leather thickness measurement according to ISO 2589.

(5) Conditioning Chamber – Maintains temperature and humidity per ISO 2419 requirements.

Frequently Asked Questions

(1) What types of leather can be tested using ISO 3377-2:2025?

All leather types, including upholstery, garment, glove, footwear, and automotive leathers.

(2) How many specimens should be tested for each sample?

Six specimens: three with the long edge parallel to the backbone and three perpendicular.

(3) Can this test determine the absolute tear resistance of leather?

It provides standardized, reproducible values for comparison, but actual in-use performance may vary based on conditions.

(4) What is the importance of specimen conditioning?

Conditioning per ISO 2419 ensures moisture and temperature equilibrium, which affects tear strength.

(5) How is the mean tear strength calculated?

Mean tear strength (N/mm) = mean tear load ÷ mean thickness of the specimen.

(6) Is the test applicable for finished leather only or also unfinished leather?

Applicable to both; it can evaluate raw, semi-finished, or finished leather.

(7) What type of reporting is required?

Reports should include mean thickness, tear loads (parallel/perpendicular), overall mean, optional N/mm, conditioning, deviations, date, and sample ID.

(8) Can the test results be used for supplier comparison?

Yes, standardized results enable objective comparison of leather from different suppliers.

(9) What maintenance is required for the instruments?

Regular calibration of the tensile machine, proper cleaning of holders and press knife, and verification of thickness gauges are essential.

(10) Can this method be automated?

Yes, modern tensile testers allow automated tear testing with digital recording for higher throughput and consistency.

Qinsun Instruments is a professional instrument equipment manufacturer, providing one-stop solutions.

2026-01-06 17:44