Designation:D6720−07(Reapproved2012)StandardTestMethodforEvaluationofRecoverableStretchofStretchYarns(SkeinMethod)1ThisstandardisissuedunderthefixeddesignationD6720;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversthedeterminationoftherecov-erablestretchofcommercialtexturedyarns,coveredelasto-mericyarnsandotherstretchyarnsusingskeins.Thistestmethodisparticularlyvaluableforyarnsthatdevelopaddi-tionalcrimpuponexposuretohot,wetconditions.Therecoverablestretchisarelativemeasureoftherecoverypowertheyarncanbeexpectedtoprovideinafinishedfabric.1.2Thistestmethodisapplicabletocontinuousfilamentyarnsandissuitableforyarnsthatdevelopadditionalstretchpotentialuponexposuretoheat.1.3Thismethodisapplicabletoyarns500denierorfiner.1.4ThevaluesstatedinSIunitsaretoberegardedasstandard.Thevaluesgiveninparenthesesareprovidedforinformationonly.1.5Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2D123TerminologyRelatingtoTextilesD1776PracticeforConditioningandTestingTextilesD4849TerminologyRelatedtoYarnsandFibers3.Terminology3.1ForallterminologyrelatingtoD13.58,YarnsandFibers,refertoTerminologyD4849.3.1.1Thefollowingtermsarerelevanttothisstandard:elastomericyarn,recoverablestretch,stretchyarn.3.2Forallothertermsarerelatedtotextiles,refertoTerminologyD123.4.SummaryofTestMethod4.1Askeinofyarnispreparedbywindingaprescribednumberofturnsonareelinordertoobtaina5000gskein.Theskeinisimmersedinboilingwaterfor15minandairdriedtoallowtheyarnskeintofullydevelopitsstretch(crimp)potential.Theskeinisexercisedunderaspecifiedtensionanditsextended...
