Designation:D3768−11StandardTestMethodforMicrocellularUrethanes—FlexuralRecovery1ThisstandardisissuedunderthefixeddesignationD3768;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope*1.1Thistestmethodcoverstheprocedureandapparatusformeasuringtheflexuralrecoveryofmicrocellularurethanes.1.2ThevaluesstatedinSIunitsaretoberegardedasstandard.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.NOTE1—ThereisnoknownISOequivalenttothisstandard.2.ReferencedDocuments2.1ASTMStandards:2D3040PracticeforPreparingPrecisionStatementsforStan-dardsRelatedtoRubberandRubberTesting(Withdrawn1987)3E691PracticeforConductinganInterlaboratoryStudytoDeterminethePrecisionofaTestMethod3.SignificanceandUse3.1Thistestmethodisusedtoindicatetheabilityofamaterialtorecoveraftera180°bendarounda12.7-mm(0.5-in.)diametermandrelatroomtemperature.3.2Beforeproceedingwiththistestmethod,referenceshouldbemadetothespecificationofthematerialbeingtested.Anytestspecimenpreparation,conditioning,ordimensions,orcombinationthereof,andtestingparameterscoveredinthematerialsspecificationshalltakeprecedenceoverthosemen-tionedinthesetestmethods.Iftherearenomaterialspecifications,thenthedefaultconditionsapply.NOTE2—Thistestmethodisapplicabletosolidurethanes.4.Apparatus4.1FlexuralRecoveryTestFixture—Thetestfixtureshallconsistofa12.7-mmdiametermandrelmountedtoabaseequippedwithaprotractor.AdrawingofatypicaltestfixtureisshowninFig.1.4.2Timer,capableofindicatingseconds.4.3ThicknessIndicator,accurateto0.03mm.5.TestSpecimens5.1Thetestspecimensshallbecutfrommoldedplaquesorparts.Therecommendedstandardtestspecimenis4mminthickness...
