ASTM_C_961_-_15.pdf

Designation:C96115Standard Test Method forLap Shear Strength of Sealants1This standard is issued under the fixed designation C961;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 lap shear strength of sealants.It also providesinformation on the adhesive bond of the sealants to the testedsubstrates.1.2 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.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.1.4 The subcommittee with jurisdiction of this standard isnot aware of any similar or equivalent ISO standard.2.Referenced Documents2.1 ASTM Standards:2C717 Terminology of Building Seals and Sealants3.Terminology3.1 DefinitionsRefer to Terminology C717 for definitionsof the following terms used in this test method:adhesivefailure,cohesive failure,sealant,standard conditions,andsubstrate.4.Summary of Test Method4.1 The sealant is placed between two glass substrates.Thesample is placed in a tensile tester and pulled at a constant rateto failure.The maximum shear force and mode of failure isnoted.Maximum shear stress is calculated and reported.5.Significance and Use5.1 Sealants are generally subjected to longitudinal andlateral shear stresses in end use applications.This test methodmeasures the cohesive strength of sealants when subjected toshear stresses,and also provides information regarding theadhesive bond to the substrates being tested.6.Apparatus6.1 Sealant Applicator or Oven,capable of maintaining thesealant within 62.8C(65F)of the specified temperature.6.2 Substrates,of annealed glass that are 25.4 mm wide by76.2 mm long and 6.35 mm thick(1 by 3 by 0.25 in.).Othersubstrates may be used when specified(Fig.1).6.3 Template,to provide 3.18-mm(18-in.)sealant thickness(Fig.2).6.4 Hot Knife or Spatula.6.5 Tension Testing Machine,capable of pulling a specimenat a rate of 12.7 mm(0.5 in.)/min.7.Sampling7.1 Sealant shall be free of external surface contaminantssuch as talc,oil,dust,and moisture.Handling of the sealantsurfaces in contact with the substrate shall be minimized.7.2 A 1.0-kg(2.2-lb)representative sample shall be takenfrom bulk stock for testing.8.Test Specimens8.1 Prepare six test specimens from the bulk sample byusing the applicator or the oven method.8.1.1 Applicator Method:8.1.1.1 Clean the substrate surface with soap and waterfollowed by a water rinse and solvent wipe with methyl ethylketone(MEK).NOTE1At the request of the sealant manufacturer,an alternativecleaning procedure may be used.8.1.1.2 Using an appropriate die or nozzle,apply a 25.4 by25.4-mm(1 by 1-in.)layer of sealant onto one end of thesubstrate surface at a thickness that when compressed willcomply with 8.1.1.4.Substrates shall be at standard conditions.Apply the sealant at the specified temperature 62.8C(65F)(Fig.1).1This test method is under the jurisdiction ofASTM Committee C24 on BuildingSeals and Sealants and is the direct responsibility of Subcommittee C24.30 onAdhesion.Current edition approved Dec.1,2015.Published January 2015.Originallyapproved in 1981.Last previous edition approved in 2011 as C96106(2011).DOI:10.1520/C0961-15.2For 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 8.1.1.3 Immediately after sealant application place a secondsubstrate onto the sealant to form an overlap of 6.45 cm2(1in.2)(Fig.1).8.1.1.4 Using a template(Fig.2),compress the overlayedsealant to form the 3.18-mm(18-in.)thick overlap(Fig.3).8.1.1.5 Remove excess sealant from the specimen with a hotknife or spatula.8.1.2 Oven Method:8.1.2.1 Clean the substrate surface with soap and waterfollowed by a water rinse and solvent wipe with MEK(Note1).8.1.2.2 Place sufficient sealant onto the substrate so thatwhen compressed,a 6.45-cm2(1-in.2)overlap that will complywith 8.1.2.4 is obtained.8.1.2.3 Separately place both the substrate with sealant andthe overlapping substrate into an oven and condition for 30 minat the specified temperature.8.1.2.4 Immediately upon removing the substrates from theoven,place the second substrate onto the sealant on the firstsubstrate(Fig.1).Using the template(Fig.2),compress theoverlayed sealant to form a 3.18-mm(18-in.)thick overlap