ASTM_D_6075_-_13.pdf

Designation:D607513Standard Test Method forCracking Resistance of Leather1This standard is issued under the fixed designation D6075;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This test method covers the determination of the resis-tance of leather to cracking when the leather is bent or foldedwith the grain(or finish)surface on the outside of the bend.Heavy leathers(for example,harness,belt,strap,bag,case,andso forth)are usually bent around a mandrel using eithermechanical 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 asharp double-fold(crosswise)bend after cooling to a lowtemperature.This test method does not apply to wet blue.1.2 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D1517 Terminology Relating to LeatherD1610 Practice for Conditioning Leather and Leather Prod-ucts for TestingD1813 Test Method for Measuring Thickness of LeatherTest Specimens3.Terminology3.1 For definitions of general leather terms used in this testmethod,refer to Terminology D1517.3.2 Definitions:3.2.1 finish crackingthe appearance of cracks(that is,ruptures)in the finish of leather which may extend through thefinish layer to the surface of the crust leather or deeper.3.2.2 grain crackingthe appearance of cracks(that is,ruptures of the grain enamel)on the grain surface of the leatherwhich may even extend deeper into the leather cross section.4.Summary of Test Method4.1 A specimen of leather is conditioned and then bent byone of three procedures.The grain(or finish)surface of thebent specimen is then examined for the appearance of anycracks or ruptures in the area around the bend.4.1.1 One bending procedure for heavier leathers involves amandrel rod,a metal bar with thickness equal to the diameterof the mandrel,and a large clamp or vise to force and hold theleather in the bent configuration around the mandrel with themetal bar placed between the flesh surfaces of the bent leather.4.1.2 A second bending procedure for heavier leathersinvolves bending the leather around a mandrel by hand andforcing and holding the leather so the flesh surfaces of the bentleather are in contact.4.1.3 Athird bending procedure for lighter leathers involvescooling the leather specimen and then creating a sharp double(crosswise)fold while the specimen remains in the coldchamber.5.Significance and Use5.1 This test method is designed to determine the crackingresistance of the grain or finish surface of leather on a pass/failbasis.This test method attempts to replicate the conditions thatmay be encountered by leather that is bent around a buckleframe or other anchoring device,folded over in seams or welts,and so forth.The cracking resistance of leather is influenced bymany factors such as quantity,location,and type of fatliquor-ing materials;moisture content;thickness;the presence ofdefects or scar tissue,or both;the presence of processingdamages to the skin or hide tissue;finish system formulation,and so forth.This test method is useful for manufacturing1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.01 on Vegetable Leather.Thistest method is a combination of three methods(that is,Methods 4011,4021,and 7211)that were part of Federal Test Method Standard No.311.This test methodwas developed in cooperation with the U.S.Defense Personnel Support Center,Directorate of Clothing and Textiles,Philadelphia,PA and the U.S.Army NatickResearch,Development and Engineering Center Natick,MA.Current edition approved May 1,2013.Published May 2013.Originallyapproved in 1997.Last previous edition approved in 2010 as D6075 00(2010).DOI:10.1520/D6075-13.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 control in the tannery,specification acceptance,and qualitycontrol in the end product manufacturing plant.6.Apparatus6.1 Vise or Clamp,shall have plain(that is,smooth and notknu