1、Designation: D2561 95 (Reapproved 2005) D2561 12Standard 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, i
2、n 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. Scope Scope*1.1 Under certain conditions of stress, and in the presence of environments suc
3、h as soaps, wetting agents, oils, or detergents,blow-molded polyethylene containers may exhibit mechanical failure by cracking at stresses appreciably below those that wouldcause cracking in the absence of these environments.1.2 This test method measures the environmental stress crack resistance of
4、containers, which is the summation of the influenceof container design, resin, blow-molding conditions, post treatment, or other factors that can affect this property. Three proceduresare provided as follows:1.2.1 Procedure A, Stress-Crack Resistance of Containers to Commercial LiquidsThis procedure
5、 is particularly useful fordetermining the effect of container design on stress-crack resistance or the stress-crack resistance of a proposed commercialpackage containing a proprietary liquid product.1.2.2 Procedure B, Stress-Crack Resistance of a Specific Container to Polyoxyethylated Nonylphenol,
6、Nonylphenol (CAS68412-54-4), a Stress-Cracking AgentThe conditions of test described in this procedure are designed for testing containers madefrom Class 3 polyethylene Specification D4976. Therefore, this procedure is recommended for containers made from Class 3polyethylene only. This procedure is
7、particularly useful for determining the effect of resin on the stress-crack resistance of thecontainer.1.2.3 Procedure C, Controlled Elevated Pressure Stress-Crack Resistance of a Specific Container to PolyoxyethylatedNonylphenol, Nonylphenol (CAS 68412-54-4), a Stress-Cracking AgentThe internal pre
8、ssure is controlled at a constant elevatedlevel.NOTE 1There are environmental concerns regarding the disposal of Polyoxyethylated Nonylphenol (Nonylphenoxy poly(ethyleneoxy) ethanol (CAS68412-54-4), for example, Igepal CO-630). Users are advised to consult their supplier or local environmental offic
9、e and follow the guidelines providedfor the proper disposal of this chemical.1.3 These procedures are not designed to test the propensity for environmental stress cracking in the neck of containers, suchas when the neck is subjected to a controlled strain by inserting a plug.1.4 The values stated in
10、 SI units are to be regarded as standard.NOTE 2There is no known ISO equivalent to this standard.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health
11、practices and determine the applicability of regulatorylimitations prior to use. Specific precautionary statements are given in Section 8 and Note 12 and Note 89.2. Referenced Documents2.1 ASTM Standards:2D374 Test Methods for Thickness of Solid Electrical InsulationD618 Practice for Conditioning Pl
12、astics for TestingD4976 Specification for Polyethylene Plastics Molding and Extrusion MaterialsD5947 Test Methods for Physical Dimensions of Solid Plastics Specimens1 This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.19
13、on Film, Sheeting, and MoldedProducts.Current edition approved July 15, 2005Aug. 1, 2012. Published August 2005September 2012. Originally approved in 1966. Last previous edition approved in 20012005as D2561 - 95 (2001).(2005). DOI: 10.1520/D2561-95R05.10.1520/D2561-12.2 For referenced ASTM standards
14、, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM
15、 standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published b
16、y ASTM is to be considered the official document.*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 States1E145 Specification for Gravity-Convection and Forced-Ventilation Ovens3.
17、 Terminology3.1 Definitions of Terms Specific to This Standard:3.2 failureduring this test method, the formation of any imperfection, such as a crack, which results in a loss of pressurizinggas or stress-cracking agent. A container has failed when:3.2.1 It has lost pressure through any aperture othe
18、r than heat seal areas; or, in Procedure C, when there is a detectable flowof supply air into the bottle,3.2.1 DiscussionA container has failed when:It has lost pressure through any aperture other than heat seal areas; or, in Procedure C, when there is a detectable flow ofsupply air into the bottle,
19、 there is any visible crack completely through the container wall, there is evidence of the containedliquid on the outside of the container through any aperture other than one at the heat-seal area, or the contained liquid volumehas been reduced.3.2.2 There is visible to an observer with normal eyes
20、ight any crack completely through the container wall, or3.2.3 There is evidence of the contained liquid on the outside of the container through any aperture other than one at theheat-seal area, or the contained liquid volume has been reduced.4. Summary of Test Method4.1 Procedure A consists of expos
21、ing any filled, sealed, blow-molded container to the action of a potential stress-cracking agentwithin the container, at an elevated temperature. The time to failure is observed.4.2 Procedure B consists of exposing a partly filled and sealed blow-molded standard container to container, partly filled
22、 to onethird of overflow capacity, to the action of polyoxyethylated nonylphenol, a stress-cracking agent, within the container, as well asto the action of this agent as an external environment, at an elevated temperature. The time to failure is observed.4.3 Procedure C consists of exposing a partly
23、 filled blow-molded standard container to blow-molded standard container, partlyfilled to one fourth of overflow capacity, to the action of polyoxyethylated nonylphenol, a stress-cracking agent, within thecontainer, as well as to a constant elevated pressure internally applied and at an elevated tem
24、perature. The time-to-failure can bedetermined in a tactual-visual manner, or instrumentally.NOTE 3Partial filling, that is, one third of nominal capacity, has been found to increase the severity of the test with many test liquids. Thus, the partialfill can be used to accelerate the test. The use of
25、 an elevated controlled pressure as in Procedure C can also accelerate the test.5. Significance and Use5.1 When properly used, these procedures may serve to isolate such factors as material, blow-molding conditions,post-treatment, and so forth, on the stress-crack resistance of the container.5.2 Env
26、ironmental stress cracking of blow-molded containers is governed by many factors. Since variance of any of thesefactors can change the environmental stress-crack resistance of the container, the test results are representative only of a given testperformed under defined conditions in the laboratory.
27、 The reproducibility of results between laboratories on containers made onmore than one machine from more than one mold has not been established.5.3 Results can be used for estimating the shelf life of blow-molded containers in terms of their resistance to environmentalstress cracking provided this
28、is done against a rigorous background of practical field experience and reproducible test data.5.4 Before proceeding with this test method, reference should be made to the specification of the material being tested. Any testspecimen preparation, conditioning, dimensions, or testing parameters, or a
29、combination thereof, covered in the materialsspecification shall take precedence over those mentioned in this test method. If there are no material specifications, then the defaultconditions apply.6. Apparatus6.1 For Procedures A, B, and C:6.1.1 Circulating-Air Oven, consistent with ovens prescribed
30、 in Specification E145, except for size, capable of maintaining atemperature of 60 6 1C (140 6 1.8F) and an airflow rate of 8.5 to 17 m3/min (300 to 600 ft3/min). (Warning Ahigh-temperature safety switch is highly recommended on this oven. Some test liquids can cause extreme pressure buildup uponhea
31、ting. Under these conditions bottles can rupture with explosive force. This condition can cause injury to the operator as wellas damage to the ovens. The override cutoff switch should be set to turn off the oven heat if the test temperature is exceeded byas much as 10C (18F). )D2561 1226.1.2 Balance
32、, accurate to within 61.0 g (for weighing containers and contents) or a volumetric filling apparatus accurate to61 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 enough to hold the conte
33、nts of one 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 bagshould fit loosely around the container and be long enough so that the bag opening can be closed above the container
34、 closure.6.4 For Procedure C Only:6.4.1 The essential parts of this apparatus are schematically shown in Fig. 1. Additional refinements in failfailure detection canbe added as shown in Fig. 2. The necessary equipment is as follows:6.4.1.1 Clear Air Supply of sufficient pressure to operate regulator
35、and maintain regulated pressure to manifold.6.4.1.2 Air Filter, to remove oil, water, dust, and other contaminants.6.4.1.3 Pressure Regulator, to reduce line pressure to 34.5 6 1.72 kPa (5.0 6 0.25 psig).6.4.1.4 Pressure Gages, calibrated to indicate a pressure of 34.5 kPa (5.0 psig) with a precisio
36、n of 0.34 kPa (0.05 psig).NOTE 4A mercurynon-mercury manometer is of benefit in calibrating the pressure gages, and monitoring precise pressure measurements.6.4.1.5 Air Valves.6.4.1.6 Restricting Line Orifice or Needle ValveThis restriction retards the flow of air to the bottle so that supply pressu
37、reremains constant after bottle failure, enabling a number of bottles to be pressurized from a single regulated supply. Pressure dropon the bottle side of this restriction is one indication of bottle failure. The orifice size or restriction used will depend upon thesensitivity of the pressure switch
38、 or gage. Orifices that pass 300 cm3 /min at 6.9 kPa (1 psi) differential pressure have been foundsatisfactory. Needle valves, which may be adjusted to flow rates as low as 5.0 cm3/min, may be useful in cases where greatersensitivity to small failures is desired.6.4.1.7 Bottle Cap AssembliesEach bot
39、tle must be securely sealed and attached to the test fixture. Assemblies essentially likethose shown in Fig. 3 have been found satisfactory.7. Reagents7.1 For Procedure AAny reagent or proprietary liquid that is potentially an environmental stress-cracking agent.7.2 For Procedure B:7.2.1 Polyoxyethy
40、lated Nonylphenol, Nonylphenol (CAS 68412-54-4), a stress-cracking agent.NOTE 5Polyoxyethylated nonylphenol is hygroscopic and the undiluted agent should be kept tightly stoppered.7.2.2 Polyoxyethylated Nonylphenol SolutionPrepare a 10 % solution, by volume, of the stress-cracking agent in distilled
41、 ordeionized water in sufficient volume to fill a minimum of fifteen 473-mL (16-oz) containers to one third of overflow capacity (178mL).NOTE 6It has been found to be helpful due to the viscosity of the stress-cracking agent, to prepare the solution at an elevated temperature. Atemperature of 50C (1
42、20F) has been found suitable.7.2.3 Dye Indicator SolutionAdd 0.1 % by weight of a wetting agent (Dioctyl sodium sulfosuccinateCAS Number577-11-7) to distilled or deionized water. Dissolve 0.001 % by weight of Gentian Violet in the water.NOTE 7Since only about 0.1 mL (2 drops) of this solution is add
43、ed to each bottle, only a small volume is needed.7.3 For Procedure C:7.3.1 Polyoxyethylated Nonylphenol, a stress-cracking agent. See Note 35.FIG. 1 Apparatus for Procedure CD2561 1237.3.2 Polyoxyethylated Nonylphenol SolutionPrepare a 3313 % solution by volume, of the stress-cracking agent in disti
44、lledor deionized water in sufficient volume to fill a minimum of fifteen 473-mL (16-oz) containers to one fourth of the overflowcapacity (133 mL). See Note 46.8. Safety Precautions8.1 Proper precautions should be taken are required to prevent overheating of the containers during testing since some p
45、roductswhich may be tested by Procedure A may causecan create an extreme pressure buildup in the container and could cause causingthe container to rupture explosively. Proper safety measures against over-heating are described in the warning note at the end of6.1.1.8.2 Sometimes a container will A co
46、ntainer can also fail by means of a small pinhole. Since the container is under pressureduring the test, liquid maycan be forced out of the opening spraying the inside of the oven and the operator, if an inspection isbeing made. Precautions to prevent this from happening are described in 11.1.411.1.
47、5.8.3 Care should it to be taken in handling the stress-cracking agent since there is somea possibility of its causing dermatitis.8.4 Proper precautions should are to be taken in handling compressed air equipment when following Procedure C.9. Test Specimen9.1 For Procedure AA minimum of 15 blow-mold
48、ed containers, representative of the lot to be tested, and fitted with a screwclosure affording a leakproof seal, shall be selected.9.2 For Procedures B and CA standard blow-molded container shall be used for this test. It is a 473-mL (16-oz) cylindricalbottle weighing approximately 20 g, as shown i
49、n Fig. 4. A minimum of 15 containers shall be selected as in 9.1. The minimumwall thickness of the container shall be not less than 0.305 mm (12 mil). The pinch-off area of the container shall not extend intothe chime radius.FIG. 2 Apparatus for Procedure C, Including Refinements in Failure DetectionFIG. 3 Bottle Pressure Seal and TubeD2561 124NOTE 8Test Methods D374D5947, 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 6 2C (73.4 6 3.6
