Designation:C581−15AnAmericanNationalStandardStandardPracticeforDeterminingChemicalResistanceofThermosettingResinsUsedinGlass-Fiber-ReinforcedStructuresIntendedforLiquidService1ThisstandardisissuedunderthefixeddesignationC581;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope1.1Thispracticeisdesignedtoevaluate,inanunstressedstate,thechemicalresistanceofthermosettingresinsusedinthefabricationofreinforcedthermosettingplastic(RTP)lami-nates.Thispracticeprovidesforthedeterminationofchangesintheproperties,describedasfollows,ofthetestspecimensandtestreagentafterexposureofthespecimenstothereagent:hardnessofspecimens,weightchangethickness,appearanceofspecimens,appearanceofimmersionmedia,andflexuralstrengthandmodulus.1.1.1Thispracticeisalsousefultoevaluateotherfactors,suchassurfacingveilsandtheeffectofresinadditives,onthechemicalresistanceoftheresin.1.2Thevaluesstatedininch-poundunitsaretoberegardedasstandard.ThevaluesgiveninparenthesesaremathematicalconversionstoSIunitsthatareprovidedforinformationonlyandarenotconsideredstandard.NOTE1—ThereisnoknownISOequivalenttothisstandard.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2D790TestMethodsforFlexuralPropertiesofUnreinforcedandReinforcedPlasticsandElectricalInsulatingMateri-alsD883TerminologyRelatingtoPlasticsD2563PracticeforClassifyingVisualDefectsinGlass-ReinforcedPlasticLaminatePartsD2583TestMethodforIndentationHardnessofRigidPlas-ticsbyMeansofaBarcolImpressorD2584TestMethodforIgnitionLossofCuredReinforcedRes...
