ASTM_D_5733_-_99.pdf

Designation:D 5733 99Standard Test Method forTearing Strength of Nonwoven Fabrics by the TrapezoidProcedure1This standard is issued under the fixed designation D 5733;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(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the measurement of the tearingstrength of nonwoven fabrics by the trapezoid procedure usinga recording constant-rate-of-extension(CRE)tensile testingmachine.1.1.1 The CRE-type tensile testing machine has become thepreferred test apparatus for determining trapezoid tearingstrength.It is recognized that some constant-rate-of-traverse(CRT)tensile testing machines continue to be used.As aconsequence,these test instruments may be used when agreedupon between the purchaser and the supplier.The conditionsfor the CRT-type tensile tester as used with this test areincluded in Appendix X1.1.2 This test method applies to most nonwoven fabricsincluding those that are treated or untreated,heavily sized,coated,or resin-treated.This test method may not be useful forhighloft nonwoven fabrics.1.3 Trapezoid tear strength as measured in this test methodis the maximum tearing force required to continue or propagatea tear started previously in the specimen.The reported value isnot directly related to the force required to initiate or start atear.1.4 The values stated in SI units are to be regarded as thestandard.The inch-pound units given in parentheses may beapproximate.1.5 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:D 76 Specification for Tensile Testing Machines for Tex-tiles2D 123 Terminology Relating to Textiles2D 1776 Practice for Conditioning Textiles for Testing2D 2904 Practice for Interlaboratory Testing of a Textile TestMethod That Produces Normally Distributed Data2D 4848 Terminology of Force,Deformation,and RelatedProperties of Textiles33.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 lengthwise direction,nin textiles,the direction in amachine-made fabric parallel to the direction of movement thefabric followed in the manufacturing machine.3.1.1.1 DiscussionFor nonwovens,an easily distinguish-able pattern for orientation may not be apparent,especially ifremoved from the roll.Care should be taken to maintain thedirectionality by clearly marking the direction.3.1.2 nonwoven fabric,na textile structure produced bybonding or interlocking of fibers,or both,accomplished bymechanical,chemical,thermal,or solvent means,or combina-tion thereof.3.1.3 tearing force,nthe average force required to con-tinue a tear previously started in a fabric.3.1.3.1 DiscussionFor nonwovens,the tearing force isrecorded as the maximum force required to continue a tearpreviously started in a fabric.The tearing force may appear asa single peak or a series of peaks on a force-extension curve,depending on the nature of the material.Typically for non-woven fabrics,if a small decrease in force occurs at a timewhen the applied force is increasing,it is not considered as apeak unless the indicated force exceeds the force required tobreak,individually or collectively,the fibers,fiber bonds,orfiber interlocks.Lower shifts corresponding to fiber movementdo not qualify as peaks since the fibers,fiber bonds,or fiberinterlocks are not broken.The trapezoid tearing force may becalculated from a single-peak or multiple-peak force-extensioncurve.3.1.4 tearing strength,nthe force required either to startor to continue or propagate a tear in a fabric followed in themanufacturing process.3.1.5 widthwise direction,nin textiles,the direction in amachine-made fabric perpendicular to the direction of move-ment the fabric followed in the manufacturing machine.3.2 DefinitionsFor definitions of other terms related toforce and deformation of textiles used in this test method,referto Terminology D 4848.For definitions of other textile terms,refer to Terminology D 123.1This test method is under the jurisdiction ofASTM Committee D-13 on Textilesand is the direct responsibility of Subcommittee D13.64 on Nonwoven Fabric.Current edition approved Nov.10,1999.Published January 2000.Originallypublished as D 5733 95.Last previous edition D 5733 95.2Annual Book of ASTM Standards,Vol 07.01.3Annual Book of ASTM Standards,Vol 07.02.1Copyright ASTM,100 Barr Harbor Drive,West Conshohocken,PA 19428-2959,United States.4.Summary of Test Method4.1 An outline of an isosceles trapezoid is marked on arectangular specimen cut for the determination of tearingstrength(see Fig.1).The specimen is slit at the center of thesmal