1、Designation: D5459 95 (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 oforigin
2、al 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 the measurement of recoveryfrom extension
3、, permanent 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 o
4、nly.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 and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenc
5、ed Documents2.1 ASTM Standards:2D882 Test Method for Tensile Properties of Thin PlasticSheetingD1898 Practice for Sampling of Plastics3D996 Terminology of Packaging and Distribution Environ-mentsD2103 Specification for Polyethylene Film and SheetingE122 Practice for Calculating Sample Size to Estima
6、te,With Specified Precision, the Average for a Characteristicof a Lot or ProcessE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 Definitions: General definitions for packaging and dis-tribution environments are found in Terminology D99
7、6.3.2 Definitions 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
8、original 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 propert
9、ies of the films 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 b
10、eing distended 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
11、A of TestMethods D882 with grips satisfactory for the purpose. Refer tosection on grips in Test Methods D882.6.2 Specimen Cutter, capable of producing nick-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 t
12、hickness ofspecimens to 0.001 in. (0.03 mm) as described in 8.9.1.1 ofSpecification D2103.1This test 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.
13、 Published May 2012. Originallyapproved in 1994. Last previous edition approved in 2007 as D5459 95 (2007).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 inform
14、ation, refer to the standards Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.4A JDC-1-10 precision cutter is available from Thwing-Albert Instrument Co.,10960 Dutton Rd. Philadelphia, PA 19154, or similar manufa
15、cturers.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7. Sampling7.1 Acceptance SamplingSampling shall be in accordancewith Practice D1898.7.2 Sampling for Other PurposesThe sampling and thenumber of test specimens depend on the pu
16、rposes 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 property of a film cannot be based on a single roll ofproduct.8. Specimen Preparation8.1 Cut five st
17、rips 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 r
18、ecord the values.9. Preparation of Apparatus9.1 Select a load range so that the scans cover approxi-mately two-thirds of the chart width.9.2 Calibrate the strain gage as directed by the manufacturerof the machine. Set the rate of grip separation at 5 in./min (127mm/min) and the initial grip separati
19、on at 5 in. (127 mm).10. Conditioning10.1 Sample ConditioningCondition the test specimens atthe standard atmospheric condition for not less than 24 h priorto testing, as described in Practice E691.10.2 Test ConditionsTesting shall be conducted under thecondition specified for specimen conditioning i
20、n 10.1.11. Procedure11.1 Clamp the first specimen in the grips so that it is freeto slack but is not under tension.11.2 Start the testing machine and chart, and elongate thespecimen at 5 in./min (127 mm/min) to an extension of 15, 50,100, 150 or 200 % and stop the testing machine and chart. (InFig.
21、1, at extension AE, curve AB is generated.)11.3 Wait 60 s or 24 h, during which time the specimen willrelax. See Note 1. (In Fig. 1, extension BG is generated.)NOTE 1Slack in the specimen and misalignment of the grips are themajor causes of non-linearity of the early part of the load-extensioncurves
22、.11.3.1 When testing materials of unknown response, inves-tigate a series of times for recovery.11.4 Return the crosshead to the original grip separation,simultaneously reversing the chart. (In Fig. 1, curve GCA isgenerated.)11.5 Wait 180 s.11.6 Re-elongate the specimen to the same extension asused
23、originally in 11.2. (In Fig. 1, curve ADX is generated.)11.7 Repeat the procedure described in 11.1-11.6 on theother four specimens.12. Calculation (See Fig. 1)12.1 Determine the length of AD and AE in chart units.Calculate the permanent deformation in percent using Eq 1:permanent deformation,%5 AD/
24、AE! 3 100 (1)12.2 Determine the lengths of DE and AE in chart units.Calculate the elastic recovery in percent using Eq 2 (see Note2):elastic recovery,%5 DE/AE! 3 100 (2)NOTE 2Percent of permanent deformation plus percent of elasticrecovery = 100 %.12.3 Determine the length of BE and GE in chart unit
25、s.Calculate the stress retention in percent using Eq 3:stress retention,%5 GE/BE! 3 100 (3)12.4 Read and record the force at point G in grams-force,lbs-force, or Newtons.12.5 Calculate the average, standard deviation, and 95 %confidence limits of the average for each factor measured,including thickn
26、ess, for each set of five specimens tested.13. Report13.1 Report the following information:13.1.1 Complete sample identification,13.1.2 Extensions tested,13.1.3 Number of specimens tested,13.1.4 Permanent deformation of each specimen and time ifdifferent than 180 s,13.1.5 Elastic recovery of each sp
27、ecimen and time if differ-ent than 180 s,13.1.6 Stress retention in both percentage and grams-forceor pounds-force and time if different in 60 s. (Stress retentioncan be reported as a plot of GE versus time),13.1.7 Thickness of each specimen, and13.1.8 Average results, standard deviations, and confi
28、dencelimits where applicable.14. Precision and Bias14.1 PrecisionThe following summaries involve five ma-terials tested by six laboratories, based on a round robinconducted in 1989, in accordance with Practice E691. EachFIG. 1 Determination of the Elastic Properties of FilmsD5459 95 (2012)2material
29、was tested at two different stretch percentages, 50 and150 %. Slabs of material were removed from each film roll,with one slab of each type being sent to each participating lab.One layer of film was removed from a slab for each repetition,and five repetitions were conducted for each test result.14.1
30、.1 Stress Retention Data at 50 % ElongationTheaverage stress retention at 50 % elongation was 70.4 % with astandard deviation of 2.6 percentage points within each labo-ratory and a standard deviation of 4.4 percentage pointsbetween laboratories; other materials may have higher or lowervariability. B
31、ased on this, the estimated 95 % repeatabilitylimits are 7.1 percentage points and the estimated reproduc-ibility limits are 12.2 percentage points.14.1.2 Stress Retention Data at 150 % ElongationTheaverage stress retention at 150 % elongation was 69.4 % witha standard deviation of 1.6 percentage po
32、ints within eachlaboratory and a standard deviation of 3.3 percentage pointsbetween laboratories; other materials may have higher or lowervariability. Based on this, the estimated 95 % repeatabilitylimits are 4.4 percentage points and the estimated reproduc-ibility limits are 9.3 percentage points.1
33、4.1.3 Permanent Deformation Data at 50 % ElongationThe average permanent deformation at 50 % elongation was24 % with a standard deviation of 1.5 percentage points withineach laboratory and a standard deviation of 1.9 percentagepoints between laboratories; other materials may have higheror lower vari
34、ability. Based on this, the estimated 95 % repeat-ability limits are 4.2 percentage points and the estimatedreproducibility limits are 5.4 percentage points.14.1.4 Permanent Deformation Data at 150 %ElongationThe average permanent deformation at 150 %elongation was 40.1 % with a standard deviation o
35、f 1.0percentage points within each laboratory and a standarddeviation of 2.7 percentage points between laboratories; othermaterials may have higher or lower variability. Based on this,the estimated 95 % repeatability limits are 2.9 percentagepoints and the estimated reproducibility limits are 7.5 pe
36、rcent-age points.14.1.5 Elastic Recovery Data at 50 % ElongationTheaverage elastic recovery at 50 % elongation was 64.4 % with astandard deviation of 1.5 percentage points within each labo-ratory and a standard deviation of 2.5 percentage pointsbetween laboratories; other materials may have higher o
37、r lowervariability. Based on this, the estimated 95 % repeatabilitylimits are 4.2 percentage points and the estimated reproduc-ibility limits are 7.1 percentage points.14.1.6 Elastic Recovery Data at 150 % ElongationTheaverage elastic recovery at 150 % elongation was 59.9 % witha standard deviation
38、of 1.0 percentage points within eachlaboratory and a standard deviation of 2.7 percentage pointsbetween laboratories; other materials may have higher or lowervariability. Based on this, the estimated 95 % repeatabilitylimits are 2.9 percentage points and the estimated reproduc-ibility limits are 7.5
39、 percentage points.14.2 BiasThe procedure in this test method has no biasbecause the values of elastic recovery, permanent deformation,and stress retention are defined in the terms of this method.15. Keywords15.1 elastic recovery; permanent deformation; stress reten-tion; stretch wrap; thin filmsAST
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43、on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D5459 95 (2012)3
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