ASTM_D_6077_-_10.pdf

Designation:D607710Standard Test Method forTrapezoid Tearing Strength of Leather1This standard is issued under the fixed designation D6077;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.1.Scope1.1 This test method covers the measurement of the tearingload of nonwoven fabrics by the trapezoid method for leather.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:2D1610 Practice for Conditioning Leather and Leather Prod-ucts for TestingD2813 Practice for Sampling Leather for Physical andChemical Tests3.Summary of Test Method3.1 An outline of a trapezoid(see Fig.1)is marked on aspecimen cut for the determination of breaking load,and thenonparallel sides of the specimen are clamped in the jaws of atensile testing machine.A continuously increasing load isapplied to the specimen in such a way that the tear propagatesacross the specimen width.The value of the breaking load ofthe specimen is obtained from the load-elongation(stress-strain)curve recorded autographically.4.Significance and Use4.1 The trapezoid tearing load is a tension test in which thetest strength is determined primarily by the interlockingstructure of the fibers.It is useful for estimating relative ease oftearing of leather.4.2 The procedure can also be used to determine if there isany appreciable difference in the relative strength of the leatherin the parallel and the perpendicular directions to the backbone.5.Apparatus5.1 Tensile Testing Machine,constant-rate-of-traverse type,equipped with an autographic recorder to register the appliedload.5.2 Clamps,with faces measuring 25 by 75 mm(1 by 3 in.)with the longer dimension perpendicular to the direction ofapplication of the load.5.3 Template,optional,having the dimensions shown in Fig.1.5.4 Pawls,bolt on a machine to allow motion in only onedirection.6.Sampling6.1 Unless otherwise specified,sample as directed,paralleland perpendicular to backbone or parallel and perpendicular tothe cut part.Sampling per Practice D2813.7.Test Specimens7.1 Unless otherwise specified,test ten specimens.7.2 Cut the test specimens parallel and perpendicular tobackbone or parallel and perpendicular to the cut part.8.Conditioning8.1 Condition the test specimens for 24 h at 21 6 2C(706 2F)and 50 6 5%relative humidity or in accordance withPractice D1610.(The customer may specify.)9.Procedure9.1 Test properly conditioned test specimens in the standardatmosphere for testing.9.2 Set the clamps at the start of the test 25 6 1 mm(1 60.05 in.)apart and operate the machine at 300 6 10 mm(12 60.40 in.)/min.Select the load range of the testing machine suchthat the break occurs between 10 and 90%of the full-scaleload.1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.05 on Upholstery.Current edition approved April 1,2010.Published May 2010.Originallyapproved in 1997.Last previous edition approved in 2005 as D6077-00(2005).DOI:10.1520/D6077-10.2For 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 9.3 Secure the test specimen in the machine,clamping alongthe nonparallel sides of the trapezoid with the cut halfwaybetween the clamps.Hold the short edge taut and let the longedge lie in folds.9.4 Start the machine with pawls disengaged,and record thetearing load on the autographic recorder.The tearing load willnot be a single value,but will appear as a series of maxima andminima.10.Calculation10.1 Visually fit a straight line parallel to the elongation axisthrough the maxima,and use this as the maximum load.Repeatthis for the minima.Take the average of these two values as thetearing load for that specimen.10.2 Separately calculate the average of the tearing load ofthe five parallel direction test specimens and the average of thefive perpendicular direction test specimens.11.Report11.1 Report the following information:11.1.1 Describe the material or product samples,11.1.2 Describe the method of sampling used,11.1.3 Report thickness,and11.1.4 tearing load.12.Precision and Bias12.1 PrecisionA coefficient of v