Designation:D2227−96(Reapproved2020)StandardSpecificationforNaturalRubber(NR)TechnicalGrades1ThisstandardisissuedunderthefixeddesignationD2227;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope1.1Thisspecificationcoversminimumphysicalandchemi-calqualityrequirementsorspecificationsforfivegradesofrawnaturalrubber.1.2Thisinternationalstandardwasdevelopedinaccor-dancewithinternationallyrecognizedprinciplesonstandard-izationestablishedintheDecisiononPrinciplesfortheDevelopmentofInternationalStandards,GuidesandRecom-mendationsissuedbytheWorldTradeOrganizationTechnicalBarrierstoTrade(TBT)Committee.2.ReferencedDocuments2.1ASTMStandards:2D1278TestMethodsforRubberfromNaturalSources—ChemicalAnalysisD1485PracticeforRubberfromNaturalSources—SamplingandSamplePreparationD1646TestMethodsforRubber—Viscosity,StressRelaxation,andPre-VulcanizationCharacteristics(MooneyViscometer)D3157TestMethodforRubberfromNaturalSources—ColorD3194TestMethodforRubberFromNaturalSources—PlasticityRetentionIndex(PRI)D3533TestMethodforRubber—NitrogenContent(With-drawn2006)33.DetailedRequirementsforGrades3.1TherubbershallconformtotherequirementsinTable1.3.2AnyrubbernotmeetingalltherequirementsforoneofthefivegradesinTable1cannotbeconsideredatechnicallygradedrubber.4.SignificanceandUse4.1Thegeneralend-usequalityofmanufacturedrubberproductsdependsonthephysicalandchemicalpropertiesoftherubber.5.Classification5.1Types—Table1coversthephysicalandchemicalre-quirementsforfivegradesofnaturalrubber:GradesL,CV,5,10,and20.6.Sampling6.1Thesamplingandsamplepreparationshallbeinaccor-dancewithPracticeD1485.7.TestMethods7.1Determinethepropertiesenumeratedinthisspecifica-tioninaccordancewithTestMethodsD1278,D3533,D3194,D3157,andD1646....
