1、Designation: D5419 14aStandard Test Method forEnvironmental Stress Crack Resistance (ESCR) of ThreadedPlastic Closures1This standard is issued under the fixed designation D5419; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the y
2、ear 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 determines the susceptibility ofthreaded plastic closures to failure due to environmental str
3、esscracking (ESC).1.2 In use, threaded plastic closures can contact agents thatappreciably reduce the stress at which cracks form. Examplesof such agents are: soaps, detergents, oils, and liquid bleaches.1.3 Major factors that influence environmental stress crackresistance (ESCR) of threaded plastic
4、 closures include theclosure material(s), closure design, molded-in stress, andapplied stress.1.4 This procedure can be applied to all closures, but isparticularly applicable to closures made from plastics based onpolypropylene (PP) or polystyrene (PS).1.5 The values stated in inch-pound units are t
5、o be regardedas the standard. The values given in parentheses are forinformation only.1.6 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 a
6、nd determine the applica-bility of regulatory limitations prior to use. Specific precau-tionary statements are given in Section 8 and 6.2.NOTE 1There is no known ISO equivalent to this standard.2. Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD883 Termino
7、logy Relating to PlasticsD1600 Terminology forAbbreviated Terms Relating to Plas-ticsD2911 Specification for Dimensions and Tolerances forPlastic BottlesE145 Specification for Gravity-Convection and Forced-Ventilation OvensE691 Practice for Conducting an Interlaboratory Study toDetermine the Precisi
8、on of a Test Method3. Terminology3.1 DefinitionsExcept for those terms below, see Termi-nologies D883 and D1600.3.2 Definitions of Terms Specific to This Standard:3.2.1 assemblyclosure applied to a bottle finish.3.2.2 failureduring this test, any visible crack.3.2.2.1 DiscussionA crack does not have
9、 to penetrate theclosure wall to be considered a failure.3.2.3 finishfixture representing the threaded portion of thebottle.3.2.4 threaded closurepart applied to seal bottle as speci-fied in Specification D2911.4. Summary of Test Method4.1 This test method consists of applying closures at aspecified
10、 application torque to rigid finishes (of polysulfone orother appropriate resin), immersing the assembly in a potentialstress-cracking agent, and observing and reporting time-to-failure.5. Significance and Use5.1 This test method compares closures for ESCR. Suitablevariables are: closure materials,
11、closure designs, processes,applied torque, and stress-crack agents.5.2 Results can be used for estimating shelf life of closuresin terms of ESCR. This requires that the user has calibratedfailure time in this test to failure time in the field for actualpackaging systems.6. Apparatus6.1 Wide-Mount Ga
12、llon Jars, glass, PET, or other suitablematerial. Must have lined closures to ensure air-tight seal. Useone jar per sample.1This test method is under the jurisdiction ofASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.19 on Film, Sheeting, andMolded Products.Current
13、 edition approved Dec. 1, 2014. Published December 2014. Originallyapproved in 1993. Last previous edition approved in 2014 as D5419 14. DOI:10.1520/D5419-14A.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of
14、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 States16.2 Circulating-Air Ove
15、n, capable of maintaining a tem-perature of 50 6 1C (critical in this application). SeeSpecification E145 for a procedure for confirming satisfactoryuniformity of temperature within the oven. There is no air-flowrequirement in this application. An environmental room withthese properties is also suit
16、able. (WarningA high-temperature safety switch is highly recommended on this oven.Some test liquids can cause extreme pressure to build up uponheating. Under these conditions it is possible that the test jarswill rupture with explosive force. Set the override cutoff switchto turn off the oven if the
17、 test temperature is exceeded by 10Cor more.)6.3 Tongs, for sample removal and inspection.6.4 Bottle Finishes, polysulfone or other material of equiva-lent stiffness and thermal coefficient of expansion, to whichclosures are applied. These can be made by injection moldingor by machining rod stock. S
18、ee Fig. 1 for a drawing of a typicalfixture. Use an appropriate size based on closure and bottlespecifications.6.5 Torque Meter, with capacity of at least 5 torque Nm,calibrated or verified within the past 12 months.6.6 Plastic Test Closures, lined or unlined closure based onspecifications.NOTE 2To
19、ensure that full crystallization has essentially beenachieved, PP-based closures should condition for at least three weeksbefore testing and PS closures for at least 16 h.NOTE 3To convert lbf-in. torque to Nm torque, multiply by 0.113.7. Reagents and Materials7.1 Test SolutionUse solution for which
20、the closure isintended.8. Hazards8.1 Always wear protective equipment, such as goggles,gloves, and aprons, appropriate to the product hazard whensetting up or inspecting closures.9. Test Specimens9.1 Normal sample size is 20 closures, typical of lots to betested. It is strongly advisable to run the
21、test in duplicate (twosets of 20) or to sample more than one lot.9.2 Visually inspect each closure to be tested. Replace anythat appear defective or irregular.NOTE 1Tolerances for Dimensions T, E, and S shall be in accordance with Specification D2911.FIG. 1 Typical FixtureD5419 14a210. Conditioning1
22、0.1 ConditioningAfter aging in accordance with 6.6,condition closures and bottle finishes at 23 6 2C and 50 610 % relative humidity for not less than 40 h prior to test, inaccordance with Procedure A of Practice D618 unless other-wise specified by agreement or the relevant ASTM materialspecification
23、. Condition test solution at 50 6 1C until itreaches 50 6 1C (16 h normally required).10.2 Test ConditionsConduct all tests at 50 6 2C, unlessinstructed otherwise.11. Procedure11.1 Apply closures to bottle finishes. Unless otherwisespecified, apply torque to a tolerance of 65 % using one of thefollo
24、wing values:11.1.1 A value corresponding to the upper limit of immedi-ate removal torque in production (rule of thumb: applicationtorque = 1.05 immediate removal torque), or11.1.2 A nominal value based on the closure diameter (ruleof thumb: torque, Nm = closure diameter, mm 0.08), or11.1.3 A value a
25、greed upon between the laboratory and thecustomer.11.1.4 Firmly position the bottle finish between the fourposts on the torque tester in such a manner that the axis ofrotation of the cap is concentric with the center of the movableplate on which the bottle finish rests.11.1.5 Grip the closure by han
26、d, avoiding any contact withthe bottle finish, and twist clockwise while closely watchingthe gauge. Apply torques smoothly and consistently, at aconstant rate consistent with accurate reading of the gauge.11.1.6 Apply torque continuously until the desired torque asindicated by the needle on the gaug
27、e is reached.11.2 Place 20 assemblies in jars. Fill jars with enough testsolution at 50 6 1C to cover all assemblies. Wipe any testsolution from jar-finish area. Cap jars and hand tighten.11.3 Place jars on test at 50 6 1C. Check and record thetemperature of test area daily and maintain it within th
28、especified limits.11.4 Inspect the assemblies daily except on weekends.Move jars from test condition to inspection area. Do not allowto be off test more than 60 min. Remove the assembliesindividually, using tongs on the bottle finishes, not the closures.NOTE 4It is recommended that the inspection fr
29、equency be increasedduring periods of known high-failure rates. Delaying the start of thesecond duplicate sample facilitates this; however, frequency of torquereapplication should remain at daily intervals except on weekends.11.5 After inspection, set aside failures. Reapply initialtorque to nonfail
30、ing closures, return them to jars and move jarsback to test condition. Do not remove or loosen closures. If testsolution degrades with age, replace it often enough that thefailure rate is not significantly reduced. If closure cracks onretorqueing, count this as a failure on the next inspection.11.6
31、For each failure, note the time, description, and loca-tion of failure.11.7 Any sample (jar) can be removed and the test termi-nated when there have been failures on at least two inspections,and a total of at least 11 out of 20 closures have failed. Recordinspections even on days when there are no f
32、ailures.NOTE 5If testing against an F50specification, the test may beterminated if no more than 1 closure out of 20 fails by the specificationtime.12. Calculation12.1 Calculate closures predicted to fail at any given timeby the following equation:failures, % 5 n 2 0.5!/N# 3100 (1)where:n = cumulativ
33、e number of closures that have failed as ofthe given time, andN = number of closures tested (20 unless otherwise stated).12.2 F25Failure TimePlot the data on Weibull probabilitygraph paper with days on the log scale and percent failure onthe probability scale. When more than one closure fails on agi
34、ven inspection, use the average % failing on that inspectionfor the plotting position (see the example in Appendix X1).Draw the best fitting straight line for the plot. The daysindicated at the intersection of the data line with the 50 %failure level probability line shall be reported as the F50fail
35、uretime. See Fig. 2 for example.NOTE 6The plot or calculations, or both, may be made on computerwith suitable software.13. Report13.1 Report the following information:FIG. 2 F50Failure TimeD5419 14a313.1.1 Closure identification, specification number (ifapplicable), manufacturer, molding location, m
36、olding date, lotnumber, liner description (if applicable), molding machine,resin, mold and cavity number(s), process conditions,13.1.2 Test solution name and composition/analysis,13.1.3 Application torque,13.1.4 Date and time of each inspection and location of eachfailure, and13.1.5 Failure time (F5
37、0).14. Precision and Bias314.1 PrecisionTable 1 is based on a round robin con-ducted in 1995 in accordance with Practice E691, involvingone material tested by 12 laboratories. All of the samples wereprepared at one source. Each test result was based on 20individual determinations. Each laboratory ob
38、tained two testresults for each material. (WarningThe following explana-tions of r and R (14.1.1.1 14.1.1.3) are only intended topresent a meaningful way of considering the approximateprecision of this test method. Do not apply the data in Table 1rigorously to the acceptance or rejection of material
39、, as thosedata are specific to the round robin and are not necessarilyrepresentative of other lots, conditions, materials, or laborato-ries. Users of this test method need to apply the principlesoutlined in Practice E691 to generate data specific to theirlaboratory and materials or between specific
40、laboratories. Theprinciples of 14.1.1.1 14.1.1.3 would then be valid for suchdata.)14.1.1 Concept of r and Rif Srand SRhave been calculatedfrom a large enough body of data,14.1.1.1 Repeatability, (r)(Comparing two test results forthe same material, obtained by the same operator using thesame equipme
41、nt on the same day.) Judge the two test results asnot equivalent if they differ by more than the r value for thatmaterial.14.1.1.2 Reproducibility, (R)(Comparing two test resultsfor the same material, obtained by different operators usingdifferent equipment on different days.) Judge the two testresu
42、lts as not equivalent if they differ by more than the R valuefor that material.14.1.1.3 Any judgment determined in accordance with14.1.1.1 and 14.1.1.2 would have an approximate 95 % (0.95)probability of being correct.14.2 BiasThere are no recognized standards by which toestimate the bias of this te
43、st method.15. Keywords15.1 closures; environmental stress crack resistance(ESCR); failure; plastic; stress crack; threaded plastic closuresAPPENDIX(Nonmandatory Information)X1. EXAMPLE OF GRAPHICAL DETERMINATION OF F50X1.1 Data (See Table X1.1):X1.2 Plotting Positions for n = 20 (See Table X1.2):X1.
44、3 X-Axis Values for Example:X1.3.1 First failures occurred at 5 days, so the first X valueis 5 days.X1.3.2 The second X value is 6 days.X1.3.3 The test terminated after 6 days (19 failures).X1.4 Y-Axis Values for Example:3A research report is currently being written.TABLE 1 F50, DaysClosures Testedi
45、n BleachAverage SrASRBrCRD28 mm-Polypropylene5.1 0.8 1.5 2.2 4.1ASris the within-laboratory standard deviation.BSRis the between-laboratories standard deviation.Cr is the within-laboratory repeatability limit = 2.8 Sr.DR is the between-laboratory reproducibility limit = 2.8 SR.TABLE X1.1 DataNo. of
46、Dayson TestNo. of Closures Failingon This DateTotal No. of ClosuresFailed to Date30 040510 169 9TABLE X1.2 Plotting Positions for n =20No. of Closures Failed Plotting Position, %12.5273 12.54 17.55 22.56 27.57 32.58 37.59 42.510 47.511 52.512 57.513 62.514 67.515 72.516 77.517 82.518 87.519 92.520 9
47、7.5D5419 14a4X1.4.1 For the first point, the Y value is the average of theplot position for 1 and 10 closures failed5 2.5147.5!/2 5 25% (X1.1)X1.4.2 For the second point, the Y value is the average ofthe plot position for 11 and 19 closures failed5 52.5192.5!/2 5 72.5% (X1.2)X1.4.3 Graph (See Fig. 2
48、):X1.5 Determination of F50Interpolate the line at the“percent failing” value of 50 on the Y-axis, and read of f “daysto failure” on the X-axis.SUMMARY OF CHANGESCommittee D20 has identified the location of selected changes to this standard since the last issue (D5419 - 14)that may impact the use of
49、 this standard. (December 1, 2014)(1) Deleted reference toASTM D3198 since it was withdrawn.(2) Added appropriate directions to Section 11 (Procedure) toaddress application of closures to bottle finish.Committee D20 has identified the location of selected changes to this standard since the last issue (D5419 - 09)that may impact the use of this standard. (November 15, 2014)(1) Editorially changed the wording of the warning note in 6.2.(2) Clarified the standard units statement in 1.5.(3) Added units of measurement to Fig. 1.ASTM Intern
