ASTM_F_904_-_98_2008.pdf

Designation:F90498(Reapproved 2008)Standard Test Method forComparison of Bond Strength or Ply Adhesion of SimilarLaminates Made from Flexible Materials1This standard is issued under the fixed designation F904;the number immediately following the designation indicates the year of originaladoption or,in the case of revision,the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon()indicates an editorial change since the last revision or reapproval.INTRODUCTIONIt has been widely discussed in the literature that bond strength of flexible multi-ply materials isimpossible to measure with current technology.The above is recognized and accepted,since all knownmethods of measurement include the force required to bend the separated layers,in addition to thatrequired to separate them.However,useful information can be obtained when one realizes that thebending force is included and that direct comparisons between different materials,or even between thesame materials of different thicknesses,cannot be made.Also,conditioning that affects the softness ormoduli of the plies will be reflected in the bond strength measurement.1.Scope1.1 This test method covers a procedure for comparing thebond strength or ply adhesion of similar laminates made fromflexible materials such as cellulose,paper,plastic film,and foil.This includes laminates made by various processes:adhesivelaminates,extrusion coatings,extrusion laminates,and coex-trusion.1.2 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are provided forinformation purposes only.1.3 This standard does not purport to address all of thesafety problems,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.Specific precau-tionary statements are given in 7.1.1.2.Referenced Documents2.1 ASTM Standards:2D882 Test Method for Tensile Properties of Thin PlasticSheetingD1898 Practice for Sampling of Plastics(Withdrawn 1998)3E691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 Definitions:3.1.1 adhesive failurefailure at the interface of two adja-cent layers.3.1.2 cohesive failurefailure within one of the two adja-cent layers comprising the bonded area under test.3.1.3 bond strengthamount of force or energy required toseparate plies of material or materials plus the force to bend theplies.3.1.4 neckinglocalized reduction in cross section whichmay occur in a material under tensile stress.3.1.5 webrefers to roll stock after it has been unwoundfrom the roll.4.Summary of Test Method4.1 Ply separation is initially started mechanically by theapplication of heat or by using a solvent.The separated plies ofthe test specimen are placed into the grips of a tensile testingmachine.The grips are then separated and the force required tofurther separate the plies is defined as bond strength.Alterna-tively,the energy may be used.NOTE1The force to bend the separated plies is included.1This test method is under the jurisdiction ofASTM Committee F02 on FlexibleBarrier Packaging and is the direct responsibility of Subcommittee F02.20 onPhysical Properties.Current edition approved April 1,2008.Published May 2008.Originallyapproved in 1984.Last previous edition approved in 2003 as F904 98(2003).DOI:10.1520/F0904-98R08.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.Significance and Use5.1 Laminates are made by bonding together two or morelayers of material or materials.Their performance is oftendependent on the ability of the laminate to function as a singleunit.If the plies have not been properly bonded together,theperformance may be adversely affected.Laminates may main-tain adequate bond strength under standard test conditions,butunder conditions of use may exhibit an increase or decrease inbond strength.Applying heat,such as in boilable pouchapplications,may adversely affect bond strength,as may coldtemperatures,such as those encountered in freezer storage offoods.Fats and oils may also influence bond strength as well asthe softness or moduli of the plies.This test method can beused to compare bond strength of similar materials and to studychanges under these and other conditions of end use,providingcaution is used with respect to the effects of the included forceto bend the separated plies.6.Apparatus6.1 GripsA gripping system that minimizes both slippageand uneven stress distribution is required.Grips lined with thinrubber,