1、Designation: D 5419 95 (Reapproved 2003)Standard Test Method forEnvironmental Stress Crack Resistance (ESCR) of ThreadedPlastic Closures1This standard is issued under the fixed designation D 5419; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、 of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method determines the susceptibility ofthreaded plastic closures to failure due t
3、o environmental stresscracking (ESC).1.2 Threaded plastic closures in use may contact agents thatappreciably reduce the stress at which cracks form. Examplesof such agents are: soaps, detergents, oils, and liquid bleaches.1.3 Other major factors that influence environmental stresscrack resistance (E
4、SCR) of threaded plastic closures are theclosure material(s), closure design, molded-in stress, andapplied stress.1.4 This procedure applies particularly to closures madefrom plastics based on polypropylene (PP) or polystyrene (PS).It may also apply to other polymers.1.5 The values stated in SI unit
5、s are to be regarded as thestandard.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 and determine the applica-bility of regulatory limi
6、tations prior to use. Specific precau-tionary statements are given in Section 8 and Note 2.NOTE 1There are no ISO standards covering the primary subject ofthis test method.2. Referenced Documents2.1 ASTM Standards:D 618 Practice for Conditioning Plastics for Testing2D 883 Terminology Relating to Pla
7、stics2D 1600 Terminology for Abbreviated Terms Relating toPlastics2D 2911 Specification for Dimensions and Tolerances forPlastic Bottles3D 3198 Test Method for Application and Removal Torqueof Threaded or Lug-Style Closures3E 145 Specification for Gravity-Convection and Forced-Ventilation Ovens4E 69
8、1 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method43. Terminology3.1 DefinitionsExcept for those terms below, see Termi-nologies D 883 and D 1600.3.2 Definitions of Terms Specific to This Standard:3.2.1 assemblyclosure applied to a bottle finish.3.2.2 failu
9、reduring this test, any visible crack.3.2.2.1 DiscussionA crack does not have 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 D 2911.4. Summary
10、of Test Method4.1 This test method consists of applying closures at aspecified 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
11、 method compares closures for ESCR. Suitablevariables are: closure materials, 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 failu
12、re time in the field for actualpackaging systems.6. Apparatus6.1 Wide-Mount Gallon Jars, glass, PET, or other suitablematerial. Must have lined closures to ensure air-tight seal. Useone jar per sample.6.2 Circulating-Air Oven, capable of maintaining a tem-perature of 50 6 1C (critical in this applic
13、ation). See1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.20 on Plastic Products.Current edition approved July 10, 2003. Published September 2003. Originallyapproved in 1993. Last previous edition approved in 1995 as
14、D 5419 95.2Annual Book of ASTM Standards, Vol 08.01.3Annual Book of ASTM Standards, Vol 15.09.4Annual Book of ASTM Standards, Vol 14.02.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Specification E 145 for a procedure for confirmin
15、g satisfactoryuniformity of temperature within the oven. There is no air-flowrequirement in this application. An environmental room withthese properties is also suitable.NOTE 2Caution: A high-temperature safety switch is highly recom-mended on this oven. Some test liquids can cause extreme pressure
16、tobuild up upon heating. Under these conditions the test jars may rupturewith explosive force. The override cutoff switch should be set to turn offthe oven if the test temperature is exceeded by 10C or more.6.3 Tongs, for sample removal and inspection.6.4 Bottle Finishes, polysulfone or other materi
17、al of equiva-lent stiffness and thermal coefficient of expansion, to whichclosures are applied. May be made by injection molding or bymachining rod stock. See Fig. 1 for drawing of typical fixture.Use appropriate size based on closure and bottle specifications.6.5 Torque Meter, with capacity of at l
18、east 5 torque Nm,calibrated or verified within the past 12 months.6.6 Plastic Test Closures, lined or unlined closure based onspecifications. PP-based closures should be at least 3 weeks oldbefore testing, and PS closures at least 16 h old. This is toensure that full crystallization has essentially
19、been achieved.NOTE 3To convert lbf-in. torque to Nm torque, multiply by 0.113.7. Reagents and Materials7.1 Test SolutionUse solution for which the closure isintended.8. Hazards8.1 Always wear protective equipment appropriate to theproduct hazard when setting up or inspecting closures. Thismay includ
20、e goggles, gloves, and aprons.9. Test Specimens9.1 Normal sample size is 20 closures, typical of lots to betested. It is strongly advisable to run the 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
21、irregular.10. Conditioning10.1 ConditioningAfter aging in accordance with 6.6,condition closures and bottle finishes at 23 6 2C and 50 65 % relative humidity for not less than 40 h prior to test, inaccordance with Procedure A of Practice D 618. Condition testsolution at 50 6 2C until it reaches 50 6
22、 2C (16 h normallyrequired).NOTE 1Tolerances for Dimensions T, E, and S shall be in accordance with Specification D 2911.FIG. 1 Typical FixtureD 5419 95 (2003)210.2 Test ConditionsConduct all tests at 50 6 2C, unlessinstructed otherwise.11. Procedure11.1 Apply closures to bottle finishes (see Test M
23、ethodD 3198). Application torque should be either of the following:11.1.1 That corresponding to the upper limit of immediateremoval torque in production (rule of thumb: applicationtorque = 1.05 3 immediate removal torque), or11.1.2 A nominal value based on the closure diameter (ruleof thumb: torque,
24、 Nm = closure diameter, mm 3 0.08), or11.1.3 A value agreed upon between the laboratory and thecustomer.11.2 Tolerance for the torque should be 65%.11.3 Place 20 assemblies in jars. Fill jars with enough testsolution at 50 6 2C to cover all assemblies. Wipe any testsolution from jar-finish area. Cap
25、 jars and hand tighten.11.4 Place jars on test at 50 6 2C. Check temperature oftest area daily and maintain within limits. Record the tempera-ture of the oven or room.11.5 Inspect the assemblies daily except on weekends.Move jars from test condition to inspection area. Do not allowto be off test mor
26、e than 60 min. Remove the assembliesindividually, using tongs on the bottle finishes, not the closures.NOTE 4Inspection frequency may be increased during periods ofknown high-failure rate. Delaying the start of the second duplicate samplefacilitates this; however, frequency of torque reapplication s
27、hould remainat daily except on weekends.11.6 After inspection, set aside failures. Reapply initialtorque to nonfailing 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
28、is not significantly reduced. If closure cracks onretorqueing, count this as a failure on the next inspection.11.7 For each failure, note the time, description, and loca-tion of failure.11.8 Any sample (jar) may be taken off test when there havebeen failures on at least two inspections, and a total
29、of at least11 out of 20 closures have failed. Record inspections even ondays when there are no failures.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
30、at any given timeby the following equation:failures, % 5 n 2 0.5!/N 3 100 (1)where:n = cumulative number of closures that have failed as ofthe given time, andN = number of closures tested (20 unless otherwisestated).12.2 F25Failure TimePlot the data on Weibull probabilitygraph paper with days on the
31、 log scale and percent failure onthe probability scale. When more than one closure fails on agiven 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 intersectio
32、n of the data line with the 50 %failure level probability line shall be reported as the F50failuretime. 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:13.1.1 Closure identification, specifi
33、cation number (if appli-cable), manufacturer, molding location, molding 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 i
34、nspection and location of eachfailure, and13.1.5 Failure time (F50).14. Precision and Bias514.1 PrecisionTable 1 is based on a round robin con-ducted in 1995 in accordance with Practice E 691, involvingone material tested by 12 laboratories. All of the samples wereprepared at one source. Each test r
35、esult was based on 20individual determinations. Each laboratory obtained two testresults for each material.5A research report is currently being written.FIG. 2 F50Failure TimeD 5419 95 (2003)3NOTE 7Caution: The following explanations of r and R (14.1.1.1-14.1.1.3) are only intended to present a mean
36、ingful way of considering theapproximate precision of this test method. The data in Table 1 should notbe applied rigorously to the acceptance or rejection of material, as thosedata are specific to the round robin and may not be representative of otherlots, conditions, materials, or laboratories. Use
37、rs of this test method shouldapply the principles outlined in Practice E 691 to generate data specific totheir laboratory and materials or between specific laboratories. Theprinciples of 14.1.1.1-14.1.1.3 would then be valid for such data.14.1.1 Concept of r and Rif Srand SRhave been calcu-lated fro
38、m 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 equipment on the same day.) The two test results shouldbe judged not equivalent if they differ by more than the r valuefor that material.14.1.1.2 Rep
39、roducibility, (R)(Comparing two test resultsfor the same material, obtained by different operators usingdifferent equipment on different days.) The two test resultsshould be judged not equivalent if they differ by more than theR value for that material.14.1.1.3 Any judgment determined in accordance
40、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 test method.15. Keywords15.1 closures; environmental stress crack resistance(ESCR); failure; plastic; stress crack; threaded pla
41、stic 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):X1.3 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
42、is 6 days.X1.3.3 The test terminated after 6 days (19 failures).X1.4 Y-Axis Values for Example:X1.4.1 For the first point, the Y value is the average of theplot position for 1 and 10 closures failed5 2.5 1 47.5!/2 5 25 % (X1.1)X1.4.2 For the second point, the Y value is the average ofthe plot positi
43、on for 11 and 19 closures failed5 52.5 1 92.5!/2 5 72.5 % (X1.2)X1.4.3 Graph (See Fig. 2):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.TABLE 1 F50, DaysThickness or OtherMaterial ConditionValues in units
44、 of _Average SrASRBrCRD28 mm 5.1 0.8 1.5 2.2 4.1PolypropyleneTested in CloroxBleachASris 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.TAB
45、LE X1.1 DataNo. of 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.
46、518 87.519 92.520 97.5D 5419 95 (2003)4ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the
47、riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of
48、this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldma
49、ke your views known to the ASTM Committee 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).D 5419 95 (2003)5
