Designation:D4640−86(Reapproved2022)StandardTestMethodforDeterminingStrokeCureTimeofThermosettingPhenol-FormaldehydeResins1ThisstandardisissuedunderthefixeddesignationD4640;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversthedeterminationofthecurerateatanyspecifiedtemperatureforathermosettingphenol-formaldehyderesin.Thetimeatthattemperaturerequiredtomakeafluidmixturechangeintoahardimmovablemassindicatesspeedofcure.1.2Thevaluesstatedininch-poundunitsaretoberegardedasstandard.ThevaluesgiveninparenthesesaremathematicalconversionstoSIunitsthatareprovidedforinformationonlyandarenotconsideredstandard.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafety,health,andenvironmentalpracticesanddeter-minetheapplicabilityofregulatorylimitationspriortouse.1.4Thisinternationalstandardwasdevelopedinaccor-dancewithinternationallyrecognizedprinciplesonstandard-izationestablishedintheDecisiononPrinciplesfortheDevelopmentofInternationalStandards,GuidesandRecom-mendationsissuedbytheWorldTradeOrganizationTechnicalBarrierstoTrade(TBT)Committee.2.Terminology2.1DefinitionsofTermsSpecifictoThisStandard:2.1.1strokecuretime,n—thetimerequiredforaresinbeingheldataspecifiedtemperatureonahotplateandbeingstrokedwithaspatula,toadheretothehotplateandnottothespatula.3.SummaryofTestMethod3.1Thistestmethodemploystheuseofcontrolledheatandathinlayerofresintodeterminethetimeinsecondsrequiredtochangefromafluidstagetoacuredimmovablestage.4.SignificanceandUse4.1Thismethodissignificantasaprocesscontrolforpolymerizationtime.4.2Whenthecuretimesaredeterminedatseveraltempera-turesandplottedastimeversustemperature,differentresinscanbecomparedforcuringcharacteristics.5.App...
