ASTM_C_771_-_14.pdf

Designation:C77114Standard Test Method forWeight Loss After Heat Aging of Preformed Tape Sealants1This standard is issued under the fixed designation C771;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers a laboratory procedure fordetermining the weight loss after heat aging of preformed tapesealants.NOTE1Test Method C681 describes a weight loss or volatility test forknife-grade glazing compounds.1.2 The values stated in acceptable metric units are to beregarded as the standard.The values given in parentheses arefor information only.1.3 The subcommittee with jurisdiction is not aware of anysimilar ISO standard.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2C681 Test Method for Volatility of Oil-and Resin-Based,Knife-Grade,Channel Glazing CompoundsC717 Terminology of Building Seals and SealantsE145 Specification for Gravity-Convection and Forced-Ventilation Ovens3.Terminology3.1 DefinitionsFor definitions of terms used in this testmethod,see Terminology C717.4.Summary of Test Method4.1 The preformed tape sealant to be tested is placed on atared metal plate and weighed.After heat aging,the specimenis weighed again.The difference in weight indicates thevolatile content of the tape sealant.5.Significance and Use5.1 Preformed tape sealants are tacky,deformable solidsthat are used under compression between two substrates in avariety of sealing applications.Compared to other types ofsealants,that is,gunnable sealants and caulks,sealing tapes aredesigned to be essentially 100%solids materials.In use,thesetapes are intended to give long service with minimal weightloss or volatility.This procedure will give a measure of theweight loss of a preformed tape sealant after a controlledperiod of exposure at an elevated temperature.6.Apparatus6.1 Balance,calibrated to weigh specimens to the nearest0.01 g.6.2 Thin Plates of Aluminum or Other Metal,two,not lessthan 51 mm(2 in.)wide by 152 mm(6 in.)long,for each tapeto be tested.6.3 Vented Air Circulating Oven,that complies with Speci-fication E145 and is capable of aging samples at 100 6 2C(212 6 3.6F).7.Sampling7.1 Use a fresh roll of preformed tape sealant for testing.Remove a section of preformed tape sealant approximately 61cm(2 ft)long from the roll and discard.7.2 Remove release paper as required in order to fashion asuitable test specimen.8.Procedure8.1 For each preformed tape sealant to be tested,preparetwo test specimens as follows:8.1.1 Clean and dry two metal plates,weigh them,andrecord the tare weight for each to the nearest 0.01 g.8.1.2 Cut the preformed tape sealant into 127-mm(5.0-in.)lengths.Ply strips together to form on each specimen plate asolid block of preformed tape sealant not less than 38 mm(1.5in.)wide by 3 mm(0.12 in.)thick by 127 mm(5.0 in.)long.8.1.3 Weigh the plates with the preformed tape sealant onthem,subtract the tare weights of the plates;determine andrecord the initial net weight for each test specimen to thenearest 0.01 g.1This test method is under the jurisdiction ofASTM Committee C24 on BuildingSeals and Sealants and is the direct responsibility of Subcommittee C24.20 onGeneral Test Methods.Current edition approved Jan.1,2014.Published January 2014.Originallyapproved in 1974.Last previous edition approved in 2009 as C771 03(2009).DOI:10.1520/C0771-14.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 8.2 Place both specimens in an air circulating oven preset to100 6 2C(212 6 3.6F)and condition them for 1 week at thistemperature.8.3 After conditioning,remove the specimens from the ovenand allow them to cool at room temperature for 1 h.8.4 Reweigh each specimen to the nearest 0.01 g and record.8.5 Subtract the respective tare weights of the plates fromthe weight of the specimens to determine the net weight of thetape specimen after heat aging,and record these weights to thenearest 0.01 g.9.Calculation9.1 For each specimen,determine the weight loss of thepreformed tape sealant by subtracting the net weight of thepreformed tape sealant after heat aging from its initial netweight.9.2 Calculate the percent weight loss for each test specimenby dividing the weight loss by the initial net weight of the tapespecimen