ASTM D2561-17 Standard Test Method for Environmental Stress-Crack Resistance of Blow-Molded Polyethylene Containers.pdf

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1、Designation: D2561 17Standard Test Method forEnvironmental Stress-Crack Resistance of Blow-MoldedPolyethylene Containers1This standard is issued under the fixed designation D2561; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the

2、 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 Under certain conditions of stress, and in the presence ofenvironments such as soaps, wetting agents, oils,

3、or detergents,blow-molded polyethylene containers exhibit mechanical fail-ure by cracking at stresses appreciably below those that wouldcause cracking in the absence of these environments.1.2 This test method measures the environmental stresscrack resistance of blow-molded containers, which is thesu

4、mmation of the influence of container design, resin, blow-molding conditions, post treatment, or other factors that canaffect this property. Three procedures are provided as follows:1.2.1 Procedure A, Stress-Crack Resistance of Containers toPotential Stress-cracking LiquidsThis procedure is particu-

5、larly useful for determining the effect of container design onstress-crack resistance or the stress-crack resistance of aproposed container that contains a liquid product.1.2.2 Procedure B, Stress-Crack Resistance of a SpecificContainer to Polyoxyethylated Nonylphenol (CAS 68412-54-4), a Stress-Crac

6、king AgentThe conditions of test describedin this procedure are designed for testing containers made fromClass 3 polyethylene Specification D4976. Therefore, thisprocedure is recommended for containers made from Class 3polyethylene only. This procedure is particularly useful fordetermining the effec

7、t of resin on the stress-crack resistance ofthe container.1.2.3 Procedure C, Controlled Elevated Pressure Stress-Crack Resistance of a Specific Container to PolyoxyethylatedNonylphenol (CAS 68412-54-4), a Stress-Cracking AgentThe internal pressure is controlled at a constant elevated level.NOTE 1The

8、re are environmental concerns regarding the disposal ofPolyoxyethylated Nonylphenol (Nonylphenoxy poly(ethyleneoxy) etha-nol (CAS 68412-54-4), for example, Igepal CO-630). Users are advised toconsult their supplier or local environmental office and follow theguidelines provided for the proper dispos

9、al of this chemical.1.3 These procedures are not designed to test the propensityfor environmental stress cracking in the neck of containers,such as when the neck is subjected to a controlled strain byinserting a plug.1.4 The values stated in SI units are to be regarded asstandard.NOTE 2There is no k

10、nown ISO equivalent to this standard.1.5 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 lim

11、itations prior to use. Specific precau-tionary statements are given in Section 8 and Note 1.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standa

12、rds, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD4976 Specification for Polyethylene Plastics Molding andExtrusion MaterialsD5947 Test Meth

13、ods for Physical Dimensions of SolidPlastics SpecimensE145 Specification for Gravity-Convection and Forced-Ventilation Ovens3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 failureduring this test method, the formation of anyimperfection, such as a crack, which results in a los

14、s ofpressurizing gas or stress-cracking agent.3.1.1.1 DiscussionA container has failed when:It has lost pressure through any aperture other than heat1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.19 on Film, Sheeting,

15、 andMolded Products.Current edition approved May 1, 2017. Published May 2017. Originallyapproved in 1966. Last previous edition approved in 2012 as D2561 - 12. DOI:10.1520/D2561-17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.or

16、g. 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 StatesTh

17、is international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (

18、TBT) Committee.1seal areas; or, in Procedure C, when there is a detectable flowof supply air into the bottle, there is any visible crackcompletely through the container wall, there is evidence ofthe contained liquid on the outside of the container throughany aperture other than one at the heat-seal

19、area, or thecontained liquid volume has been reduced.3.1.2 potential stress-cracking liquidsa liquid that cancontain stress-cracking agents, which have the potential toinduce a stress crack in the test containers.3.1.2.1 DiscussionUnder certain conditions of stress andin the presence of potential st

20、ress-cracking liquids such assoaps, wetting agents, oils, or detergents, ethylene plastics mayexhibit mechanical failure by cracking.3.1.3 stress crackdefined as a failure.4. Summary of Test Method4.1 Procedure A consists of exposing any filled, sealed,blow-molded container to the action of a potent

21、ial stress-cracking agent within the container, at an elevated temperature.The time to failure is observed.4.2 Procedure B consists of exposing a sealed blow-moldedstandard container, partly filled to one third of overflowcapacity, to the action of polyoxyethylated nonylphenol, astress-cracking agen

22、t, within the container, as well as to theaction of this agent as an external environment, at an elevatedtemperature. The time to failure is observed.4.3 Procedure C consists of exposing a blow-molded stan-dard container, partly filled to one fourth of overflow capacity,to the action of polyoxyethyl

23、ated nonylphenol, a stress-cracking agent, within the container, as well as to a constantelevated pressure internally applied and at an elevated tem-perature. The time-to-failure can be determined in a tactual-visual manner, or instrumentally.NOTE 3Partial filling, that is, one third of nominal capa

24、city, has beenfound to increase the severity of the test with many test liquids. Thus, thepartial fill can be used to accelerate the test. The use of an elevatedcontrolled pressure as in Procedure C can also accelerate the test.5. Significance and Use5.1 When properly used, these procedures serve to

25、 isolatesuch factors as material, blow-molding conditions, post-treatment, and so forth, on the stress-crack resistance of thecontainer.5.2 Environmental stress cracking of blow-molded contain-ers is governed by many factors. Since variance of any of thesefactors can change the environmental stress-

26、crack resistance ofthe container, the test results are representative only of a giventest performed under defined conditions in the laboratory. Thereproducibility of results between laboratories on containersmade on more than one machine from more than one mold hasnot been established.5.3 Results ca

27、n be used for estimating the shelf life ofblow-molded containers in terms of their resistance to envi-ronmental stress cracking provided this is done against arigorous background of practical field experience and repro-ducible test data.6. Apparatus6.1 For Procedures A, B, and C:6.1.1 Circulating-Ai

28、r Oven, consistent with ovens pre-scribed in Specification E145, except for size, capable ofmaintaining a temperature of 60 6 1C (140 6 1.8F) and anairflow rate of 8.5 to 17 m3/min (300 to 600 ft3/min).(Warning A high-temperature safety switch is highly rec-ommended on this oven. Some test liquids c

29、an cause extremepressure buildup upon heating. Under these conditions bottlescan rupture with explosive force. This condition can causeinjury to the operator as well as damage to the ovens. Theoverride cutoff switch should be set to turn off the oven heat ifthe test temperature is exceeded by as muc

30、h as 10C (18F). )6.1.2 Balance, accurate to within 61.0 g (for weighingcontainers and contents) or a volumetric filling apparatusaccurate to 61 mL.6.2 For Procedures A and B Only:6.2.1 Heat-Seal Laminate for sealing the containers.6.2.2 Heat-Sealing Unit.6.2.3 Torque Meter.6.2.4 Glass Beakers, large

31、 enough to hold the contents ofone test container.6.3 For Procedures A and C Only:6.3.1 Polyethylene Bags, approximately 0.038-mm (1.5-mil) thick, large enough to enclose completely a test container.The bag should fit loosely around the container and be longenough so that the bag opening can be clos

32、ed above thecontainer closure.6.4 For Procedure C Only:FIG. 1 Apparatus for Procedure CD2561 1726.4.1 The essential parts of this apparatus are schematicallyshown in Fig. 1.Additional refinements in failure detection canbe added as shown in Fig. 2. The necessary equipment is asfollows:6.4.1.1 Clear

33、Air Supply of sufficient pressure to operateregulator and maintain regulated pressure to manifold.6.4.1.2 Air Filter, to remove oil, water, dust, and othercontaminants.6.4.1.3 Pressure Regulator, to reduce line pressure to 34.56 1.72 kPa (5.0 6 0.25 psig).6.4.1.4 Pressure Gauges, calibrated to indic

34、ate a pressure of34.5 kPa (5.0 psig) with a precision of 0.34 kPa (0.05 psig).NOTE 4A non-mercury manometer is of benefit in calibrating thepressure gauges, and monitoring precise pressure measurements.6.4.1.5 Air Valves.6.4.1.6 Restricting Line Orifice or Needle ValveThis re-striction retards the f

35、low of air to the bottle so that supplypressure remains constant after bottle failure, enabling anumber of bottles to be pressurized from a single regulatedsupply. Pressure drop on the bottle side of this restriction is oneindication of bottle failure. The orifice size or restriction usedwill depend

36、 upon the sensitivity of the pressure switch orgauge. Orifices that pass 300 cm3/min at 6.9 kPa (1 psi)differential pressure have been found satisfactory. Needlevalves, which can be adjusted to flow rates as low as 5.0cm3/min, can be useful in cases where greater sensitivity tosmall failures is desi

37、red.6.4.1.7 Bottle Cap AssembliesEach bottle must be se-curely sealed and attached to the test fixture. Assembliesessentially like those shown in Fig. 3 have been foundsatisfactory.7. Reagents7.1 For Procedure AAny reagent or proprietary liquid thatis potentially an environmental stress-cracking age

38、nt.7.2 For Procedure B:7.2.1 Polyoxyethylated Nonylphenol (CAS 68412-54-4), astress-cracking agent.NOTE 5Polyoxyethylated nonylphenol is hygroscopic and the undi-luted agent should be kept tightly stoppered.7.2.2 Polyoxyethylated Nonylphenol SolutionPrepare a10 % solution, by volume, of the stress-c

39、racking agent indistilled or deionized water in sufficient volume to fill aminimum of fifteen 473-mL (16-oz) containers to one third ofoverflow capacity (178 mL).NOTE 6It has been found to be helpful due to the viscosity of thestress-cracking agent, to prepare the solution at an elevated temperature

40、.A temperature of 50C (120F) has been found suitable.7.2.3 Dye Indicator SolutionAdd 0.1 % by weight of awetting agent (Dioctyl sodium sulfosuccinateCAS Number577-11-7) to distilled or deionized water. Dissolve 0.001 % byweight of Gentian Violet in the water.NOTE 7Since only about 0.1 mL (2 drops) o

41、f this solution is added toeach bottle, only a small volume is needed.7.3 For Procedure C:7.3.1 Polyoxyethylated Nonylphenol, a stress-crackingagent. See Note 5.7.3.2 Polyoxyethylated Nonylphenol SolutionPrepare a3313 % solution by volume, of the stress-cracking agent indistilled or deionized water

42、in sufficient volume to fill aminimum of fifteen 473-mL (16-oz) containers to one fourth ofthe overflow capacity (133 mL). See Note 6.8. Safety Precautions8.1 Proper precautions are required to prevent overheatingof the containers during testing since some products tested byProcedure A can create an

43、 extreme pressure buildup in thecontainer causing the container to rupture explosively. Propersafety measures against over-heating are described in thewarning note at the end of 6.1.1.8.2 A container can also fail by means of a small pinhole.Since the container is under pressure during the test, liq

44、uid canbe forced out of the opening spraying the inside of the oven andthe operator, if an inspection is being made. Precautions toprevent this from happening are described in 11.1.5.8.3 Care it to be taken in handling the stress-cracking agentsince there is a possibility of its causing dermatitis.8

45、.4 Proper precautions are to be taken in handling com-pressed air equipment when following Procedure C.9. Test Specimen9.1 For Procedure AA minimum of 15 blow-moldedcontainers, representative of the lot to be tested, and fitted witha screw closure affording a leakproof seal, shall be selected.9.2 Fo

46、r Procedures B and CA standard blow-moldedcontainer shall be used for this test. It is a 473-mL (16-oz)cylindrical bottle weighing approximately 20 g, as shown inFig. 4. A minimum of 15 containers shall be selected as in 9.1.The minimum wall thickness of the container shall be not lessthan 0.305 mm

47、(12 mil). The pinch-off area of the containershall not extend into the chime radius.FIG. 2 Apparatus for Procedure C, Including Refinements in Failure DetectionD2561 173NOTE 8Test Methods D5947, modified to use a ball tip micrometer,can be used to measure the thickness of the container.10. Condition

48、ing10.1 ConditioningCondition the test specimens at 23 62C (73.4 6 3.6F) for not less than 40 h prior to test inaccordance with Procedure A of Practice D618 unless in-structed otherwise. In cases of disagreement, the tolerance shallbe 61C (61.8F).10.2 Test ConditionsConduct all tests at 60C, unlessi

49、nstructed otherwise.FIG. 3 Bottle Pressure Seal and TubeNOTE 1Dimensions are in millimetres with inches in parentheses.FIG. 4 Standard 473-mL (16-oz) Blown ContainerD2561 17411. Procedure11.1 Procedure A:11.1.1 Obtain a minimum of 15 containers of the type andsize chosen for test. Fill each to nominal capacity with thechosen test liquid, usually a potential stress-cracking liquid oran aqueous solution of polyoxyethylated nonylphenol. Avoidspilling the solution on the outside of the container since thismight lead to prema