ISO 23910_{Leather - Physical and mechanical tests -Measurement of stitch tear resistance}

Test summary

This ISO Standard specifies a method for determining the stitch tear resistance of leather.  It can be used on all leathers but is particualy suitable for leathers over 1.2 mm in thickness

A leather test piece is pulled against a mandrel of specified shape and dimensions inserted through a slit in the leather and the force required to tear the leather is recorded.

Test apparatus

Force testing stand with suitable loadcell capable of measuring displacement while applying a constant speed of grip separation.  Complimentary software for recording load and displacement and calculating results

Metal test piece holder as specified in the standard.

Grips with minimum length of 25 mm in the direction of the load designed to apply a constant clamping force by mechanical of pneumatic means.

Cutting apparatus

A thickness gauge

Preparation

From the sample, cut at least three test pieces to the dimensions given in the standard with the long axis parallel to the backbone, and three test pieces perpendicular to the backbone

Measure the thickness of the test piece in accordance with ISO 2589 at a single point on each of the test pieces. This measurement should be taken at a point approximately 10 mm from the cut end of the slit.

Test method

Place the perforated end of the test piece between the arms of the test piece holder and pass the mandrel through both the holes in the test piece holder and the slit in the test piece.

Clamp the free end of the test piece in the lower jaw of the tensile testing machine.

Start the test stand moving at a constant speed of grip separation at 100 mm/min.

Continue applying force at a constant speed until the sample breaks.

Record the the maximum force in newtons during the tearing

Report  the thickness on the leather in mm, the mean tear force in newtons for the test pieces cut parallel to the backbone, and for the test pieces cut perpendicular to the backbone,