ASTM_C_765_-_97_2015.pdf

Designation:C76597(Reapproved 2015)Standard Test Method forLow-Temperature Flexibility of Preformed Tape Sealants1This standard is issued under the fixed designation C765;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 fortesting the low-temperature flexibility of preformed tape seal-ants.1.2 The values stated in SI units are to be regarded as thestandard.The values in parentheses are for information only.1.3 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:2C717 Terminology of Building Seals and SealantsE145 Specification for Gravity-Convection and Forced-Ventilation Ovens3.Terminology3.1 DefinitionsThe definitions of the following terms usedin this test method are found in Terminology C717:preformedtape sealant,sealant.4.Summary of Test Method4.1 The preformed tape sealant to be tested is applied to analuminum panel.The assembly is heat aged,then placed in thefreezer where the panel is quickly bent over a mandrel.Thespecimen is examined for cracking and loss of adhesion.5.Significance and Use5.1 Preformed tape sealants are tacky,deformable solidsthat are used under compression between two substrates in avariety of sealing applications.This procedure is not intendedto simulate an actual use condition,but it will give someindication of the flexibility and adhesion of a tape at lowtemperature.It can serve to differentiate between flexible tapesthat can take some movement and those that tend to harden orembrittle on aging and crack or lose adhesion when flexed atlow temperature.It will also aid in identifying sealants thathave poor flexibility because they are overextended andcontain a low level of binder as well as those sealants havingbinders that will embrittle at low temperature.6.Apparatus6.1 Freezer Unit,capable of maintaining a temperature of23 6 2C(10 6 3.6F).6.2 Aluminum Panel(unpolished),approximately 0.635 mm(0.025 in.)thick,76 mm(3 in.)wide,and 152 mm(6 in.)long.6.3 Steel Mandrel,25.4 mm(1 in.)in diameter,withsupporting holder or rack.6.4 Vented Air Circulating Oven,that complies with Speci-fication E145 and is capable of maintaining a temperature of 706 2C(158 6 3.6F).7.Sampling7.1 Samples to be tested shall be taken from a fresh roll oftape sealant after first removing and discarding approximatelythe first 0.61 m(2 ft)of the roll.8.Test Specimen8.1 Prepare the test specimen as follows:8.1.1 Clean the 76-mm by 152-mm(3-in.by 6-in.)alumi-num panel with methyl ethyl ketone or similar solvent.8.1.2 Place a 102-mm(4-in.)length of tape in the center ofthe panel with its length paralleling that of the panel,leavingthe release paper in place on the preformed tape sealant.8.1.3 Apply light finger pressure to ensure intimate contactof the preformed tape sealant with the panel.8.1.4 Remove the release paper from the test specimen.9.Conditioning9.1 Place the specimen in a horizontal position in a forced-draft oven and condition for 14 days at 70 6 2C(158 63.6F).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 June 1,2015.Published July 2015.Originally approvedin 1973.Last previous edition approved in 2011 as C76597(2011).DOI:10.1520/C0765-97R15.2For 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 9.2 Remove the test specimen from the oven and immedi-ately place it in a horizontal position in a freezer unitmaintained at 236 2C(10 6 3.6F)for 4 h.9.3 Condition the steel mandrel with its holder or rack in thefreezer in the same manner.10.Procedure10.1 After the specimen and mandrel have been conditionedfor 4 h and while they are still in the freezer at 23 6 2C(106 3.6F),bend the test specimen 180 around the mandrel,with the aluminum panel next to the mandrel,using no morethan 2 s to make the bend.10.2 Visually examine the specimen for cracking or loss ofadhesion of tape to panel,or both,and estimate the area of suchadhesion loss to the nearest 64.5 mm2(0.1 in.2).11.Report11.1 Report the following information:11.1.1 Identification of the preformed tape sealant,that is,the name,lot number,and any other identifying char