1、Designation:D545995(Reapproved 2012)Standard Test Method forMachine Direction Elastic Recovery and PermanentDeformation and Stress Retention of Stretch Wrap Film1This standard is issued under the fixed designation D5459;the number immediately following the designation indicates the year oforiginal a
2、doption 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 the measurement of recoveryfrom extension,permanent
3、deformation,and stress retention ofstretch wrap film.1.2 Several levels of extension are included to ascertain theeffect of both small and large extensions.1.3 The values stated in inch-pound units are to be regardedas the standard.The SI units given in parentheses are forinformation only.1.4 This s
4、tandard 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 AS
5、TM Standards:2D882 Test Method for Tensile Properties of Thin PlasticSheetingD1898 Practice for Sampling of Plastics(Withdrawn 1998)3D996 Terminology of Packaging and Distribution Environ-mentsD2103 Specification for Polyethylene Film and SheetingE122 Practice for Calculating Sample Size to Estimate
6、,WithSpecified Precision,the Average for a Characteristic of aLot or ProcessE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 DefinitionsGeneral definitions for packaging and dis-tribution environments are found in Terminology D996.3.2 D
7、efinitions of Terms Specific to This Standard:3.2.1 elastic recoverythe percentage of a given deforma-tion that behaves elastically,after 180 s when subjected to theextensions prescribed in this test method.3.2.2 permanent deformationthe increase in length,ex-pressed as a percentage of the original
8、length,by which anelastic material fails to return to original length after subjectedto the extensions prescribed in the test procedure in thismethod.3.2.3 stress retentionthe percentage of stress retained 60 sor 24 h,or both,after application.4.Summary of Test Method4.1 Elastic properties of the fi
9、lms are determined by sub-jecting specimens to known extensions and by measuring thequantity of recovery and the permanent change with respect tothe original dimensions.5.Significance and Use5.1 Elastic recovery is related to the ability of a package toresume its original shape after being distended
10、 during its usecycle.5.2 Elastic recovery also relates to the tightness or snugnessof a package.5.3 Stress retention is related to the tightness or snugness ofa package.6.Apparatus6.1 Tensile Testing Machine,with a reversible chart,com-plying with the requirements listed for Method A of Test1This te
11、st method is under the jurisdiction of ASTM Committee D10 onPackaging and is the direct responsibility of Subcommittee D10.25 on Palletizingand Unitizing of Loads.Current edition approved April 1,2012.Published May 2012.Originallyapproved in 1994.Last previous edition approved in 2007 as D5459 95(20
12、07).DOI:10.1520/D5459-95R12.2For 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 his
13、torical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 Methods D882 with grips satisfactory for the purpose.Refer tosection on grips in Test Methods D882.6.2 Specimen Cutter,capable of producing nick
14、-free 1 60.001 in.(25.4 6 0.03 mm)testing strips,with a precision of1 6 0.001 in.(25.4 6 0.03 mm).46.3 Micrometer,capable of measuring the thickness ofspecimens to 0.001 in.(0.03 mm)as described in 8.9.1.1 ofSpecification D2103.7.Sampling7.1 Acceptance SamplingSampling shall be in accordancewith Pra
15、ctice D1898.7.2 Sampling for Other PurposesThe sampling and thenumber of test specimens depend on the purposes of thetesting.Practice E122 is recommended.Test specimens aretaken from several rolls of film,and when possible,fromseveral production runs of a product.Strong conclusions abouta specific p
16、roperty of a film cannot be based on a single roll ofproduct.8.Specimen Preparation8.1 Cut five strips parallel to the machine direction that are1.0 in.(25.4 mm)wide and long enough to provide for aninitial grip separation of 5 in.(127 mm).8.2 Measure the thickness of each specimen at five equallyspaced points in the area that will be between the grips to thenearest 0.001 in.(0.003 mm)and record the values.9.Preparation of Apparatus9.1 Select a load range so that the scans cover approxi-mately t