ASTM D6075-13(R2020) pdf free download

ASTM D6075-13(R2020) pdf free download.Standard Test Method for Cracking Resistance of Leather
1. Scope
1.1 This test method covers the determination of the resis- tance of leather to cracking when the leather is bent or folded with the grain (or finish) surface on the outside of the bend. Heavy leathers (for example, harness, belt, strap, bag, case, and so forth) are usually bent around a mandrel using either mechanical resistance (for example, clamp, vise, and so forth) or by hand. Lighter leathers (for example, shoe upper, upholstery, garment, glove, and so forth) are usually given a sharp double-fold (crosswise) bend after cooling to a low temperature. This test method does not apply to wet blue. 1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.4 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
4. Summary of Test Method
4.1 A specimen of leather is conditioned and then bent by one of three procedures. The grain (or finish) surface of the bent specimen is then examined for the appearance of any cracks or ruptures in the area around the bend. 4.1.1 One bending procedure for heavier leathers involves a mandrel rod, a metal bar with thickness equal to the diameter of the mandrel, and a large clamp or vise to force and hold the leather in the bent configuration around the mandrel with the metal bar placed between the flesh surfaces of the bent leather. 4.1.2 A second bending procedure for heavier leathers involves bending the leather around a mandrel by hand and forcing and holding the leather so the flesh surfaces of the bent leather are in contact. 4.1.3 A third bending procedure for lighter leathers involves cooling the leather specimen and then creating a sharp double (crosswise) fold while the specimen remains in the cold chamber.
5. Significance and Use
5.1 This test method is designed to determine the cracking resistance of the grain or finish surface of leather on a pass/fail basis. This test method attempts to replicate the conditions that may be encountered by leather that is bent around a buckle frame or other anchoring device, folded over in seams or welts, and so forth. The cracking resistance ofleather is influenced by many factors such as quantity, location, and type of fatliquor- ing materials; moisture content; thickness; the presence of defects or scar tissue, or both; the presence of processing damages to the skin or hide tissue; finish system formulation, and so forth. This test method is useful for manufacturing control in the tannery, specification acceptance, and quality control in the end product manufacturing plant.
6. Apparatus
6.1 Vise or Clamp, shall have plain (that is, smooth and not knurled or roughened) jaws not less than 7 cm (2 3 ⁄ 4 in.) wide. 6.2 Mandrel, shall be a rod approximately 15 cm (6 in.) in length and shall have a diameter as specified in the material specification. 6.3 Metal Bar, shall be approximately 15 cm (6 in.) in length, 1.9 cm ( 3 ⁄ 4 in.) in width, and shall have a thickness equal to the diameter ofthe mandrel as specified in the material specification. 6.4 Low-temperature Chamber, shall be capable of main- taining the required temperature (usually 0°C) to within 6 1°C and equipped so as to permit insertion of hands to hold and manipulate the leather specimen within the chamber.