BS EN ISO 17235:2002 Leather – Physical and mechanical tests – Determination of softness
The text of ISO 17235:2002 has been approved by CEN as EN ISO 17235:2002 w ithout any modifications.
NOTE: Nor mative references to International Standards are listed in Annex ZA (normative).
1.0Scope
This International Standard specifies a non-destructive method for determining the softness of a leather. It is applicable to all non-rigid leathers e.g. shoe upper leather, upholstery leather, leathergoods leather and apparel leather.
2.0Normative References
The follow ing referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 2418Leather – Chemical, physical and mechanical and fastness tests – Sampling location
ISO 2419Leather – Physical and mechanical tests – Sample preparation and conditioning
3.0Principle
A cylindrical rod of defined mass is low ered at a specified rate onto a securely clamped area of leather. The distension of the leather produced is recorded as the softness.
4.0Apparatus
4.1Test machine, show n diagrammatically in Figure 1, including the parts described in 4.1.1 to 4.1.7.
4.1.1Circular aperture, A, diameter 35,0mm ± 0,1mm.
4.1.2Metal rings, able to fit into aperture A and reduce the diameter of the aperture to 25,0mm ± 0,1mm and 20,0mm ± 0,1mm respectively.
NOTE: The apertures described above are more conveniently referred to by their nominal diameters of 35mm, 25mm and 20mm respectively.
4.1.3Clamps, B, capable of holding the leather securely both before the load pin is released and w hen the maximum force is applied, w hilst leaving the portion over the aperture free to move.
4.1.4Cylindrical load pin, C, diameter 4,9mm ± 0,1mm and length 11, 5mm ± 0,1mm rigidly attached to a cylindr ical mass, D. The total mass of load pin and cylindrical mass shall be 530g ± 10g.
4.1.5Means of guiding the load pin, such that the load pin acts perpendicularly to the leather surface and the vertical travel of the load pin in restricted to a distance 11,5mm ± 0,1mm.
4.1.6Means of lowering the load pin, such that the load pin travels its full permitted distance of 11,5mm ± 0,1mm in 1,5s ± 0,5s.
4.1.7Gauge, reading to 0,1mm, to directly measure the distension of the leather by the load pin.
Figure 1 – Diagrammatic layout of the test machine
4.2Flat rigid metal disc, minim um diameter 60mm .
5.0Sampling and Sample Preparation
Condition the leather in accordance w ith ISO 2419
NOTE: It may be possible to take measurements w ithout physically cutting a sample from the hide or skin.
6.0Procedure
6.1Select the aperture from 35mm, 25mm or 20mm.
NOTE: It is suggested that the apertures are used as follow s:
▪35mm – measurement of firmer leathers, for example, shoe upper leather;
▪25mm – measurement of leathers of moderate softness, for example, upholstery leathers and softer shoe upper leathers;
▪20mm – measurement of softer leathers, for example, apparel leathers.
6.2Open the test machine, and place the metal disc (4.2) over the circular aperture.
6.3Raise the load pin and close the test machine to clamp the metal disc in position.
6.4Release the load pin, allow the reading on the gauge to become steady and set to zero. Open the test machine and remove the metal disc.
6.5Place the area of the leather defined in ISO 2418 over the aperture ensuring that the leather lies flat, there are no obvious defects such as flay cuts or scar tissue over the aperture and that there is sufficient leather to allow effective clamping.
6.6Raise the load pin and close the test machine to clamp the leather in position.
6.7Release the load pin, allow the reading on the gauge to become steady and record the reading. Open the test machine and remove the leather.
6.8Take three readings and report the mean and the range.
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