ISO 17131-2020 pdf free.Leather —Identification of leatherwith microscopy.
This document specifies a method using microscopy to identify leather and distinguish it from othermaterials. The method is not applicable for identifying specific leathers (e.g.sheep leather).
The following documents are referred to in the text in such a way that some or all of their contentconstitutes requirements of this document.For dated references, only the edition cited applies.Forundated references, the latest edition of the referenced document (including any amendments) applies.
A cross-section of the material is cut perpendicular to the surface.The material structure is comparedwith typical pictures or known samples by means of microscopy.The method should be carried out by operators experienced in material identification by microscopy.
Light microscope (optical,phase-contrast or stereo) or scanning electron microscope,capable of giving a normal magnification of at least 20×.
NOTE For some materials it is necessary to use a microscope with a magnification of 500. Razor blade, capable of cutting a clean cross-section in leather, if the microscope illuminates fromabove or a scanning electron microscope is used.Cryomicrotome, if the microscope illuminates from below or a phase-contrast microscope is used.Coating unit, sputter or evaporation, including a suitable element or alloy (e.g.gold) for coating, ifa scanning electron microscope is used.Specimen stubs, suitable for a scanning electron microscope, if used.
From the material being tested, cut two test pieces approximately 10 mm × 10 mm using a suitablecutting device and then section each of the test pieces in accordance with 6.2 or 6.3.Place the cutting edge of the razor blade (5.2) with the blade perpendicular to the surface andpress the blade through the whole thickness of the test piece, ensuring that the blade remains verticaland the section is cleanly cut. If the test piece is considered to be leather, make the cut with the flesh orinner side uppermost.NOTE 1 lt is useful to prepare the second test piece section perpendicular to the first.
NOTE2 A section made as in 6.2 is suitable for examination under a microscope illuminated from above or byscanning electron microscopy.Place the leather sample soaked in water in a cryomicrotome (5.3〕 and cut a slice of appropriatethickness.
NOTE A section made as in 6.3 is suitable for examination under a microscope illuminated from below or aphase-contrast optical-microscope. lt is useful with a dark sample or a sample with transparent coating.When using a scanning electron microscope, ensure that the prepared section adheres to aspecimen stub(5.5) with the cut surface uppermost. Coat the stub and section in the coating unit (5.4) sothat good image quality can be obtained.
Place the sections under the microscope and compare the material structure with Figures A.1 toA.12 in Annex A (scanning electron microscope photos),Figures B.1 to B.12 in Annex B (light microscopephotos] and/or Figures C.1 to C.3 in Annex C (phase contrast cross-section photos), or with knownreference materials (5.6).Use a suitable magnification to distinguish the typical fibre structure of leatherfrom other materials. Consider the appropriate terms for leather defined in EN 15987.For the absolute identification of leather it is necessary to identify the more or less intact originalfibrous structure.ISO 17131 pdf download.