Designation:F1921/F1921M−12´1StandardTestMethodsforHotSealStrength(HotTack)ofThermoplasticPolymersandBlendsComprisingtheSealingSurfacesofFlexibleWebs1ThisstandardisissuedunderthefixeddesignationF1921/F1921M;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ε1NOTE—DesignationwascorrectededitoriallyinOctober2013.1.Scope1.1Thesetwotestmethodscoverlaboratorymeasurementofthestrengthofheatsealsformedbetweenthermoplasticsurfacesofflexiblewebs,immediatelyafterasealhasbeenmadeandbeforeitcoolstoambienttemperature(hottackstrength).1.2Thesetestmethodsarerestrictedtoinstrumentedhottacktesting,requiringatestingmachinethatautomaticallyheatsealsaspecimenandimmediatelydeterminesstrengthofthehotsealatapreciselymeasuredtimeafterconclusionofthesealingcycle.Anadditionalprerequisiteisthattheoperatorshallhavenoinfluenceonthetestafterthesealingsequencehasbegun.Thesetestmethodsdonotcovernon-instrumentedmanualproceduresemployingsprings,levers,pulleysandweights,wheretestresultscanbeinfluencedbyoperatortechnique.1.3Twovariationsoftheinstrumentedhottacktestaredescribedinthesetestmethods,differingprimarilyintworespects:(a)rateofgripseparationduringtestingofthesealedspecimen,and(b)whetherthetestingmachinegeneratesthecoolingcurveofthematerialundertest,orinsteadmakesameasurementofthemaximumforceobservedfollowingasetdelaytime.Bothtestmethodsmaybeusedtotestallmaterialswithinthescopeofthesetestmethodsandwithintherangeandcapacityofthemachineemployed.TheyaredescribedinSection4.1.4SIunitsarepreferredandshallbeusedinrefereedecisions.Valuesstatedhereinininch-poundunitsaretoberegardedseparatelyandmaynotbeexactequivalentstoSIunits.Therefore,eachsystemshallbeusedindependentlyoftheother.Combiningvaluesfromthetwosystemsmayresultinnon-conformancewiththestandard.1.5Thisstandarddoesnotpurporttoaddressall...
