Designation:D2731−21StandardTestMethodforElasticPropertiesofElastomericYarns(CRETypeTensileTestingMachines)1ThisstandardisissuedunderthefixeddesignationD2731;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversthedeterminationofelasticpropertiesof“asproduced”elastomericyarnsmadefromrubber,spandexorotherelastomers.Elasticpropertiesincludeforceatspecifiedelongations,permanentdeformationandstressdecay.Otherhysteresisrelatedpropertiescanbecalcu-lated.NOTE1—Foramethoddesignedspecificallyfortestingrubberthreads,refertoTestMethodD2433.1.2Thistestmethodisnotapplicabletocovered,wrapped,orcore-spunyarnsoryarnsspunfromelastomericstaple.1.3Thistestmethodisapplicabletoelastomericyarnshavingarangeof40to3200dtex(36to2900denier).1.4ThevaluesstatedineitherSIunitsorU.S.Customaryunitsaretoberegardedseparatelyasstandard.Withinthetext,theU.S.Customaryunitsareinparentheses.Thevaluesstatedineachsystemarenotexactequivalents;therefore,eachsystemshallbeusedindependentlyoftheother.1.5Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafety,health,andenvironmentalpracticesanddeter-minetheapplicabilityofregulatorylimitationspriortouse.1.6Thisinternationalstandardwasdevelopedinaccor-dancewithinternationallyrecognizedprinciplesonstandard-izationestablishedintheDecisiononPrinciplesfortheDevelopmentofInternationalStandards,GuidesandRecom-mendationsissuedbytheWorldTradeOrganizationTechnicalBarrierstoTrade(TBT)Committee.2.ReferencedDocuments2.1ASTMStandards:2D76SpecificationforTensileTestingMachinesforTextilesD123TerminologyRelatingtoTextilesD1776PracticeforConditioningandTestingTextilesD2258PracticeforSamplingYarnforTestingD2433TestMethodsforRubberThread(Withdra...
