ASTM_D_3420_-_14.pdf

Designation:D342014Standard Test Method forPendulum Impact Resistance of Plastic Film1This standard is issued under the fixed designation D3420;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 resistanceof film to impact-puncture penetration.Knowledge of how theimpact energy is absorbed by the specimen while it is deform-ing under the impact loading,and the behavior of the specimenafter yielding,is not provided by this test.No provision is madefor nonambient temperatures in this test method.1.2 The values stated in SI units are to be regarded as thestandard.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.Specific hazardsstatements are given in Section 7.NOTE1There is no known ISO equivalent to this standard.2.Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD883 Terminology Relating to PlasticsD1709 Test Methods for Impact Resistance of Plastic Filmby the Free-Falling Dart MethodD1922 Test Method for Propagation Tear Resistance ofPlastic Film and Thin Sheeting by Pendulum MethodD4272 Test Method for Total Energy Impact of Plastic FilmsBy Dart DropD6988 Guide for Determination of Thickness of Plastic FilmTest SpecimensE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 DefinitionsDefinitions of terms relating to plastics nototherwise described in this test method shall be in accordancewith Terminology D883.3.2 Definitions of Terms Specific to This Standard:3.2.1 failure completion energythe energy necessary toinitiate failure plus the energy necessary to cause completerupture to the test specimen.3.2.2 failure initiated energythe energy necessary to beginfailure of the test specimen.3.2.3 pendulum impact resistancethe resistance to failureof plastic film is measured by loss in mechanical work capacitydue to the expenditure of kinetic energy by a pendulum.4.Summary of Test Method4.1 The energy necessary to burst and penetrate the centerof a specimen,mounted between two plates with a circularaperture,is measured by the loss in mechanical work-capacitydue to the expenditure of kinetic energy by a pendulum,therounded probe of which passes through the test specimen.Corrections for“toss factor”or kinetic energy imparted to thepuncture fragment of the test specimen are not made,as onlytiny masses are involved.The pendulum head hits the speci-men with a maximum velocity of about 74 m/min and amaximum energy of about 5 J(50 cmkgf).5.Significance and Use5.1 Like other techniques to measure toughness,this testmethod provides a means to determine parameters of a materialat strain rates closer to some end-use applications than pro-vided by low-speed uniaxial tensile tests.Dynamic tensilebehavior of a film is important,particularly when the film isused as a packaging material.The same uncertainties aboutcorrelations with thickness that apply to other impact tests alsoapply to this test(see section 3.4 of Test Methods D1709).Hence,no provision for rationalizing to unit thickness isprovided.Also,no provision is made for testing at non-ambienttemperatures.5.2 This test method includes two procedures,similar ex-cept with regard to sample size:Procedure A for 60-mmdiameter and Procedure B for 89-mm diameter(commonlycalled the“Spencer”).The data have not been shown relatableto each other.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 Dec.1,2014.Published December 2014.Originallyapproved in 1975.Last previous edition approved in 2008 as D3420 08a.DOI:10.1520/D3420-14.2For 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.*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 States1 5.3 Several impact test methods are used for film.It issometimes desirable to know the relationships among testresults derived by different methods.A study was conducted inwhich four films made from two resins(polypropylene andlinear low-density polyethylene),with two film thicknesses foreach resin,were impacted using Test