1、Designation: D 2561 95 (Reapproved 2005)Standard Test Method forEnvironmental Stress-Crack Resistance of Blow-MoldedPolyethylene Containers1This standard is issued under the fixed designation D 2561; the number immediately following the designation indicates the year oforiginal adoption or, in the c
2、ase 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 Under certain conditions of stress, and in the presence ofenvironments such as soaps, we
3、tting agents, oils, or detergents,blow-molded polyethylene containers may exhibit mechanicalfailure by cracking at stresses appreciably below those thatwould cause cracking in the absence of these environments.1.2 This test method measures the environmental stresscrack resistance of containers, whic
4、h is the summation of theinfluence of container design, resin, blow-molding conditions,post treatment, or other factors that can affect this property.Three procedures are provided as follows:1.2.1 Procedure A, Stress-Crack Resistance of Containers toCommercial LiquidsThis procedure is particularly u
5、seful fordetermining the effect of container design on stress-crackresistance or the stress-crack resistance of a proposed commer-cial package containing a proprietary liquid product.1.2.2 Procedure B, Stress-Crack Resistance of a SpecificContainer to Polyoxyethylated Nonylphenol, a Stress-CrackingA
6、gentThe conditions of test described in this procedure aredesigned for testing containers made from Class 3 polyethyleneSpecification D 4976. Therefore, this procedure is recom-mended for containers made from Class 3 polyethylene only.This procedure is particularly useful for determining the effecto
7、f resin on the stress-crack resistance of the container.1.2.3 Procedure C, Controlled Elevated Pressure Stress-Crack Resistance of a Specific Container to PolyoxyethylatedNonylphenol, a Stress-Cracking AgentThe internal pressureis controlled at a constant elevated level.1.3 These procedures are not
8、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 1There is no similar or equivalent ISO standard.1.5 This standa
9、rd 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. Specific precau-tionary state
10、ments are given in Section 8 and Note 1 and Note8.2. Referenced Documents2.1 ASTM Standards:2D 374 Test Methods for Thickness of Solid Electrical Insu-lationD 618 Practice for Conditioning Plastics for TestingD 4976 Specification for Polyethylene Plastics Molding andExtrusion MaterialsE 145 Specific
11、ation for Gravity-Convection and Forced-Ventilation Ovens3. Terminology3.1 Definitions of Terms Specific to This Standard:3.2 failureduring this test method, the formation of anyimperfection, such as a crack, which results in a loss ofpressurizing gas or stress-cracking agent.Acontainer has failedwh
12、en:3.2.1 It has lost pressure through any aperture other thanheat seal areas; or, in Procedure C, when there is a detectableflow of supply air into the bottle,3.2.2 There is visible to an observer with normal eyesightany crack completely through the container wall, or3.2.3 There is evidence of the c
13、ontained liquid on theoutside of the container through any aperture other than one atthe heat-seal area, or the contained liquid volume has beenreduced.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.20 on Plastic Prod
14、ucts.Current edition approved July 15, 2005. Published August 2005. Originallyapproved in 1966. Last previous edition approved in 2001 as D 2561 - 95 (2001).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of AS
15、TMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4. Summary of Test Method4.1 Procedure A consists of exposing any filled, sealed,blow-mol
16、ded container to the action of a potential stress-cracking agent within the container, at an elevated temperature.The time to failure is observed.4.2 Procedure B consists of exposing a partly filled andsealed blow-molded standard container to the action of poly-oxyethylated nonylphenol,3a stress-cra
17、cking agent, within thecontainer, as well as to the action of this agent as an externalenvironment, at an elevated temperature. The time to failure isobserved.4.3 Procedure C consists of exposing a partly filled blow-molded standard container to the action of polyoxyethylatednonylphenol, a stress-cr
18、acking agent, within the container, aswell as to a constant elevated pressure internally applied and atan elevated temperature. The time-to-failure can be determinedin a tactual-visual manner, or instrumentally.5. Significance and Use5.1 When properly used, these procedures may serve toisolate such
19、factors as material, blow-molding conditions,post-treatment, and so forth, on the stress-crack resistance ofthe container.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-crack resistan
20、ce 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 can be used for
21、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.5.4 Before proceeding with this test method, referenceshould be made to the s
22、pecification of the material being tested.Any test specimen preparation, conditioning, dimensions, ortesting parameters, or a combination thereof, covered in thematerials specification shall take precedence over those men-tioned in this test method. If there are no material specifica-tions, then the
23、 default conditions apply.6. Apparatus6.1 For Procedures A, B, and C:6.1.1 Circulating-Air Oven, consistent with ovens pre-scribed in Specification E 145, 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
24、A high-temperature safety switch is highly recom-mended on this oven. Some test liquids can 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 sw
25、itch should be set to turn off the oven heat ifthe test temperature is exceeded by as much 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 Laminate4for seal
26、ing the containers.6.2.2 Heat-Sealing Unit.5,66.2.3 Torque Meter.7,66.2.4 Glass Beakers, large 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
27、 should fit loosely around the container and be longenough so that the bag opening can be closed above thecontainer closure.6.4 For Procedure C Only:6.4.1 The essential parts of this apparatus are schematicallyshown in Fig. 1. Additional refinements in fail detection can beadded as shown in Fig. 2.
28、The necessary equipment is asfollows:6.4.1.1 Clear Air Supply of sufficient pressure to operateregulator and maintain regulated pressure to manifold.3The sole source of supply of the Igepal CO-630 (Antarox CO-630) known tothe committee at this time is GAF Corp., Dyestuff and Chemical Div., 140 W. 51
29、 St.,New York, NY 10020.4The sole source of supply of the polyethylene-foil laminate (aluminum seal)known to the committee at this time is Berlin Packaging, 111 North Canal St., Suite300, Chicago, IL 60606.5The sole source of supply of the Selector Hand Sealing Iron (165 W) known tothe committee at
30、this time is Selector of Shelton, CT.6If you are aware of alternative suppliers, please provide this information toASTM International Headquarters. Your comments will receive careful consider-ation at a meeting of the responsible technical committee,1which you may attend.7The sole source of supply o
31、f the Model 25 Owens-Illinois Spring Torque Testerknown to the committee at this time is Owens-Illinois Glass Co., Toledo, OH.FIG. 1 Apparatus for Procedure CD 2561 95 (2005)26.4.1.2 Air Filter, to remove oil, water, dust, and othercontaminants.6.4.1.3 Pressure Regulator, to reduce line pressure to
32、34.56 1.72 kPa (5.0 6 0.25 psig).6.4.1.4 Pressure Gages, calibrated to indicate a pressure of34.5 kPa (5.0 psig) with a precision of 0.34 kPa (0.05 psig).NOTE 2A mercury manometer is of benefit in calibrating the pressuregages, and monitoring precise pressure measurements.6.4.1.5 Air Valves.6.4.1.6
33、Restricting Line Orifice or Needle ValveThis re-striction retards the flow 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 oneindica
34、tion of bottle failure. The orifice size or restriction usedwill depend upon the sensitivity of the pressure switch or gage.Orifices that pass 300 cm3/min at 6.9 kPa (1 psi) differentialpressure have been found satisfactory. Needle valves, whichmay be adjusted to flow rates as low as 5.0 cm3/min, ma
35、y beuseful in cases where greater sensitivity to small failures isdesired.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 prop
36、rietary liquidthat is potentially an environmental stress-cracking agent.7.2 For Procedure B:7.2.1 Polyoxyethylated Nonylphenol, a stress-crackingagent.3NOTE 3Polyoxyethylated nonylphenol is hygroscopic and the undi-luted agent should be kept tightly stoppered.7.2.2 Polyoxyethylated Nonylphenol Solu
37、tionPrepare a10 % solution, by volume, of the stress-cracking agent indistilled water in sufficient volume to fill a minimum of fifteen473-mL (16-oz) containers to one third of overflow capacity(178 mL).NOTE 4It has been found to be helpful due to the viscosity of thestress-cracking agent, to prepar
38、e the solution at an elevated temperature.A temperature of 50C (120F) has been found suitable.7.2.3 Dye Indicator SolutionAdd 0.1 % by weight of awetting agent8to distilled water. Dissolve 0.001 % by weightof Gentian Violet in the water.NOTE 5Since only about 0.1 mL (2 drops) of this solution is add
39、ed toeach bottle, only a small volume is needed.7.3 For Procedure C:7.3.1 Polyoxyethylated Nonylphenol, a stress-crackingagent.3See Note 3.7.3.2 Polyoxyethylated Nonylphenol SolutionPrepare a3313 % solution by volume, of the stress-cracking agent indistilled water in sufficient volume to fill a mini
40、mum of fifteen473-mL (16-oz) containers to one fourth of the overflowcapacity (133 mL). See Note 4.8. Safety Precautions8.1 Proper precautions should be taken to prevent overheat-ing of the containers during testing since some products whichmay be tested by Procedure A may cause an extreme pressureb
41、uildup in the container and could cause the container torupture explosively. Proper safety measures against over-heating are described in the warning note at the end of 6.1.1.8.2 Sometimes a container will fail by means of a smallpinhole. Since the container is under pressure during the test,liquid
42、may be forced out of the opening spraying the inside ofthe oven and the operator, if an inspection is being made.Precautions to prevent this from happening are described in11.1.4.8.3 Care should be taken in handling the stress-crackingagent since there is some possibility of its causing dermatitis.8
43、.4 Proper precautions should 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
44、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
45、(12 mil). The pinch-off area of the containershall not extend into the chime radius.8The sole source of supply of the Aerosol OT Solution known to the committeeat this time is Fisher Scientific Corp., 203 Fisher Building, Pittsburgh, PA 15219.FIG. 2 Apparatus for Procedure C, Including Refinements i
46、n Failure DetectionD 2561 95 (2005)3NOTE 6Test Methods D 374, modified to use a ball tip micrometer,may be used to measure the thickness of the container.10. Conditioning10.1 ConditioningCondition the test specimens at 23 62C (73.4 6 3.6F) and 50 6 5 % relative humidity for not lessthan 40 h prior t
47、o test in accordance with Procedure A ofPractice D 618 for those tests where conditioning is required.In cases of disagreement, the tolerances shall be 61C(61.8F) and 62 % relative humidity.FIG. 3 Bottle Pressure Seal and TubeNOTE 1Dimensions are in millimetres with inches in parentheses.FIG. 4 Stan
48、dard 473-mL (16-oz) Blown ContainerD 2561 95 (2005)410.2 Test ConditionsConduct all tests at 60C, unlessinstructed otherwise.11. 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
49、 proprietary liquid product or anaqueous solution of polyoxyethylated nonylphenol.NOTE 7Partial filling, that is, one third of nominal capacity, has beenfound to increase the severity of the test with many test liquids. Thus, thepartial fill may be used to accelerate the test. The use of an elevatedcontrolled pressure as in Procedure C may also accelerate the test.11.1.2 Heat-seal the containers with a suitable triple lami-nate, polyethylene side to bottle. Apply a polyethylene orsuitably lined closure with sufficient torque to ensure a doubleseal
