ASTM_D_1938_-_19.pdf

Designation:D193819Standard Test Method forTear-Propagation Resistance(Trouser Tear)of Plastic Filmand Thin Sheeting by a Single-Tear Method1This standard is issued under the fixed designation D1938;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.Scope*1.1 This test method covers the determination of the forcenecessary to propagate a tear in plastic film and thin sheeting(thickness of 1 mm(0.04 in.)or less)by a single-tear method.The method is not applicable for film or sheeting materialwhere brittle failures occur during testing.NOTE1Film has been arbitrarily defined as sheeting having nominalthickness not greater than 0.25 mm(0.010 in.).1.2 Constant-Rate-of-Grip Separation TestThis testmethod employs a constant rate of separation of the gripsholding the test specimen.1.2.1 Specimen extension may be measured in this testmethod by grip separation.1.3 The values stated in SI units are to be regarded asstandard.The values given in parentheses are provided forinformation only.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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.NOTE2This standard is similar to ISO 6383-1,but is not consideredtechnically equivalent.The specimen size for ISO 6383-1 is larger,and themethod specifies different test speeds.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD882 Test Method for Tensile Properties of Thin PlasticSheetingD883 Terminology Relating to PlasticsD4000 Classification System for Specifying Plastic Materi-alsD5947 Test Methods for Physical Dimensions of SolidPlastics SpecimensD6988 Guide for Determination of Thickness of Plastic FilmTest SpecimensE4 Practices for Force Verification of Testing MachinesE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ISO Standard:ISO 6383-1 Film and SheetingDetermination of Tear Re-sistance Part 1 Trouser Tear Method33.Terminology3.1 DefinitionsFor definitions of terms used in this testmethod,refer to Terminology D883.4.Summary of Test Method4.1 The force to propagate a tear across a film or sheetingspecimen is measured using a constant-rate-of-grip separationmachine as described in Test Methods D882 and is calculatedfrom the load-time chart.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.19 on Film,Sheeting,andMolded Products.Current edition approved April 1,2019.Published May 2019.Originallyapproved in 1962.Last previous edition approved in 2014 as D1938 14.DOI:10.1520/D1938-19.2For 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.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 5.Significance and Use5.1 This test method is of value in rating the tear-propagation resistance of various plastic films and thin sheetingof comparable thickness.For highly extensible film or sheetingthe deformation energy of the specimen legs is significantlygreater than the tearing energy.The tear-propagation resistancein slightly extensible or non-extensible film or sheeting isdistinguished from the tear-propagation resistance in highlyextensible film or sheeting by the load-time or load-displacement data,(Fig.1 and Fig.2).The tear-propagationforce for slightly extensible or non-extensible material isdetermined from the average tear force versus the initial andpeak force for a highly extensible material.5.2 This test method shall be