ASTM D2561-17(2023)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D2561 − 17 (Reapproved 2023)
Standard Test Method for
Environmental Stress-Crack Resistance of Blow-Molded
Polyethylene Containers
This standard is issued under the fixed designation D2561; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.3 These procedures are not designed to test the propensity
for environmental stress cracking in the neck of containers,
1.1 Under certain conditions of stress, and in the presence of
such as when the neck is subjected to a controlled strain by
environments such as soaps, wetting agents, oils, or detergents,
inserting a plug.
blow-molded polyethylene containers exhibit mechanical fail-
1.4 The values stated in SI units are to be regarded as
ure by cracking at stresses appreciably below those that would
standard.
cause cracking in the absence of these environments.
NOTE 2—There is no known ISO equivalent to this standard.
1.2 This test method measures the environmental stress
1.5 This standard does not purport to address all of the
crack resistance of blow-molded containers, which is the
safety concerns, if any, associated with its use. It is the
summation of the influence of container design, resin, blow-
responsibility of the user of this standard to establish appro-
molding conditions, post treatment, or other factors that can
priate safety, health, and environmental practices and deter-
affect this property. Three procedures are provided as follows:
mine the applicability of regulatory limitations prior to use.
1.2.1 Procedure A, Stress-Crack Resistance of Containers to
Specific precautionary statements are given in Section 8 and
Potential Stress-cracking Liquids—This procedure is particu-
Note 1.
larly useful for determining the effect of container design on
1.6 This international standard was developed in accor-
stress-crack resistance or the stress-crack resistance of a
dance with internationally recognized principles on standard-
proposed container that contains a liquid product.
ization established in the Decision on Principles for the
1.2.2 Procedure B, Stress-Crack Resistance of a Specific
Development of International Standards, Guides and Recom-
Container to Polyoxyethylated Nonylphenol (CAS 68412-54-
mendations issued by the World Trade Organization Technical
4), a Stress-Cracking Agent—The conditions of test described
Barriers to Trade (TBT) Committee.
in this procedure are designed for testing containers made from
Class 3 polyethylene Specification D4976. Therefore, this
2. Referenced Documents
procedure is recommended for containers made from Class 3
2.1 ASTM Standards:
polyethylene only. This procedure is particularly useful for
D618 Practice for Conditioning Plastics for Testing
determining the effect of resin on the stress-crack resistance of
D4976 Specification for Polyethylene Plastics Molding and
the container.
Extrusion Materials
1.2.3 Procedure C, Controlled Elevated Pressure Stress-
D5947 Test Methods for Physical Dimensions of Solid
Crack Resistance of a Specific Container to Polyoxyethylated
Plastics Specimens
Nonylphenol (CAS 68412-54-4), a Stress-Cracking Agent—
E145 Specification for Gravity-Convection and Forced-
The internal pressure is controlled at a constant elevated level.
Ventilation Ovens
NOTE 1—There are environmental concerns regarding the disposal of
Polyoxyethylated Nonylphenol (Nonylphenoxy poly(ethyleneoxy) etha- 3. Terminology
nol (CAS 68412-54-4), for example, Igepal CO-630). Users are advised to
3.1 Definitions of Terms Specific to This Standard:
consult their supplier or local environmental office and follow the
3.1.1 failure—during this test method, the formation of any
guidelines provided for the proper disposal of this chemical.
imperfection, such as a crack, which results in a loss of
pressurizing gas or stress-cracking agent.
This test method is under the jurisdiction of ASTM Committee D20 on Plastics
and is the direct responsibility of Subcommittee D20.19 on Film, Sheeting, and
Molded Products. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 1, 2023. Published November 2023. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1966. Last previous edition approved in 2017 as D2561 - 17. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D2561-17R23. the ASTM website.
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D2561 − 17 (2023)
3.1.1.1 Discussion—A container has failed when: ronmental stress cracking provided this is done against a
It has lost pressure through any aperture other than heat rigorous background of practical field experience and repro-
seal areas; or, in Procedure C, when there is a detectable flow ducible test data.
of supply air into the bottle, there is any visible crack
6. Apparatus
completely through the container wall, there is evidence of
the contained liquid on the outside of the container through
6.1 For Procedures A, B, and C:
any aperture other than one at the heat-seal area, or the
6.1.1 Circulating-Air Oven, consistent with ovens pre-
contained liquid volume has been reduced.
scribed in Specification E145, except for size, capable of
maintaining a temperature of 60 6 1°C (140 6 1.8°F) and an
3.1.2 potential stress-cracking liquids—a liquid that can
3 3
airflow rate of 8.5 to 17 m /min (300 to 600 ft /min).
contain stress-cracking agents, which have the potential to
(Warning— A high-temperature safety switch is highly rec-
induce a stress crack in the test containers.
ommended on this oven. Some test liquids can cause extreme
3.1.2.1 Discussion—Under certain conditions of stress and
pressure buildup upon heating. Under these conditions bottles
in the presence of potential stress-cracking liquids such as
can rupture with explosive force. This condition can cause
soaps, wetting agents, oils, or detergents, ethylene plastics may
injury to the operator as well as damage to the ovens. The
exhibit mechanical failure by cracking.
override cutoff switch should be set to turn off the oven heat if
3.1.3 stress crack—defined as a failure.
the test temperature is exceeded by as much as 10°C (18°F). )
6.1.2 Balance, accurate to within 61.0 g (for weighing
4. Summary of Test Method
containers and contents) or a volumetric filling apparatus
accurate to 61 mL.
4.1 Procedure A consists of exposing any filled, sealed,
blow-molded container to the action of a potential stress-
6.2 For Procedures A and B Only:
cracking agent within the container, at an elevated temperature.
6.2.1 Heat-Seal Laminate for sealing the containers.
The time to failure is observed.
6.2.2 Heat-Sealing Unit.
6.2.3 Torque Meter.
4.2 Procedure B consists of exposing a sealed blow-molded
6.2.4 Glass Beakers, large enough to hold the contents of
standard container, partly filled to one third of overflow
one test container.
capacity, to the action of polyoxyethylated nonylphenol, a
stress-cracking agent, within the container, as well as to the
6.3 For Procedures A and C Only:
action of this agent as an external environment, at an elevated 6.3.1 Polyethylene Bags, approximately 0.038-mm (1.5-
temperature. The time to failure is observed.
mil) thick, large enough to enclose completely a test container.
The bag should fit loosely around the container and be long
4.3 Procedure C consists of exposing a blow-molded stan-
enough so that the bag opening can be closed above the
dard container, partly filled to one fourth of overflow capacity,
container closure.
to the action of polyoxyethylated nonylphenol, a stress-
cracking agent, within the container, as well as to a constant 6.4 For Procedure C Only:
6.4.1 The essential parts of this apparatus are schematically
elevated pressure internally applied and at an elevated tem-
perature. The time-to-failure can be determined in a tactual- shown in Fig. 1. Additional refinements in failure detection can
be added as shown in Fig. 2. The necessary equipment is as
visual manner, or instrumentally.
follows:
NOTE 3—Partial filling, that is, one third of nominal capacity, has been
6.4.1.1 Clear Air Supply of sufficient pressure to operate
found to increase the severity of the test with many test liquids. Thus, the
regulator and maintain regulated pressure to manifold.
partial fill can be used to accelerate the test. The use of an elevated
6.4.1.2 Air Filter, to remove oil, water, dust, and other
controlled pressure as in Procedure C can also accelerate the test.
contaminants.
6.4.1.3 Pressure Regulator, to reduce line pressure to 34.5
5. Significance and Use
6 1.72 kPa (5.0 6 0.25 psig).
5.1 When properly used, these procedures serve to isolate
6.4.1.4 Pressure Gauges, calibrated to indicate a pressure of
such factors as material, blow-molding conditions, post-
34.5 kPa (5.0 psig) with a precision of 0.34 kPa (0.05 psig).
treatment, and so forth, on the stress-crack resistance of the
NOTE 4—A non-mercury manometer is of benefit in calibrating the
container.
pressure gauges, and monitoring precise pressure measurements.
5.2 Environmental stress cracking of blow-molded contain-
6.4.1.5 Air Valves.
ers is governed by many factors. Since variance of any of these
6.4.1.6 Restricting Line Orifice or Needle Valve—This re-
factors can change the environmental stress-crack resistance of
striction retards the flow of air to the bottle so that supply
the container, the test results are representative only of a given
pressure remains constant after bottle failure, enabling a
test performed under defined conditions in the laboratory. The
number of bottles to be pressurized from a single regulated
reproducibility of results between laboratories on containers
supply. Pressure drop on the bottle side of this restriction is one
made on more than one machine from more than one mold has
indication of bottle failure. The orifice size or restriction used
not been established.
will depend upon the sensitivity of the pressure switch or
5.3 Results can be used for estimating the shelf life of gauge. Orifices that pass 300 cm /min at 6.9 kPa (1 psi)
blow-molded containers in terms of their resistance to envi- differential pressure have been found satisfactory. Needle
D2561 − 17 (2023)
FIG. 1 Apparatus for Procedure C
FIG. 2 Apparatus for Procedure C, Including Refinements in Failure Detection
valves, which can be adjusted to flow rates as low as 5.0 7.3.2 Polyoxyethylated Nonylphenol Solution—Prepare a
cm /min, can be useful in cases where greater sensitivity to 33 ⁄3 % solution by volume, of the stress-cracking agent in
small failures is desired. distilled or deionized water in sufficient volume to fill a
6.4.1.7 Bottle Cap Assemblies—Each bottle must be se- minimum of fifteen 473-mL (16-oz) containers to one fourth of
curely sealed and attached to the test fixture. Assemblies the overflow capacity (133 mL). See Note 6.
essentially like those shown in Fig. 3 have been found
satisfactory. 8. Safety Precautions
8.1 Proper precautions are required to prevent overheating
7. Reagents
of the containers during testing since some products tested by
7.1 For Procedure A—Any reagent or proprietary liquid that
Procedure A can create an extreme pressure buildup in the
is potentially an environmental stress-cracking agent.
container causing the container to rupture explosively. Proper
7.2 For Procedure B: safety measures against over-heating are described in the
warning note at the end of 6.1.1.
7.2.1 Polyoxyethylated Nonylphenol (CAS 68412-54-4), a
stress-cracking agent.
8.2 A container can also fail by means of a small pinhole.
NOTE 5—Polyoxyethylated nonylphenol is hygroscopic and the undi- Since the container is under pressure during the test, liquid can
luted agent should be kept tightly stoppered.
be forced out of the opening spraying the inside of the oven and
the operator, if an inspection is being made. Precautions to
7.2.2 Polyoxyethylated Nonylphenol Solution—Prepare a
prevent this from happening are described in 11.1.5.
10 % solution, by volume, of the stress-cracking agent in
distilled or deionized water in sufficient volume to fill a
8.3 Care it to be taken in handling the stress-cracking agent
minimum of fifteen 473-mL (16-oz) containers to one third of
since there is a possibility of its causing dermatitis.
overflow capacity (178 mL).
8.4 Proper precautions are to be taken in handling com-
NOTE 6—It has been found to be helpful due to the viscosity of the
pressed air equipment when following Procedure C.
stress-cracking agent, to prepare the solution at an elevated temperature.
A temperature of 50°C (120°F) has been found suitable.
9. Test Specimen
7.2.3 Dye Indicator Solution—Add 0.1 % by weight of a
wetting agent (Dioctyl sodium sulfosuccinate—CAS Number 9.1 For Procedure A—A minimum of 15 blow-molded
577-11-7) to distilled or deionized water. Dissolve 0.001 % by
containers, representative of the lot to be tested, and fitted with
weight of Gentian Violet in the water. a screw closure affording a leakproof seal, shall be selected.
NOTE 7—Since only about 0.1 mL (2 drops) of this solution is added to
9.2 For Procedures B and C—A standard blow-molded
each bottle, only a small volume is needed.
container shall be used for this test. It is a 473-mL (16-oz)
7.3 For Procedure C: cylindrical bottle weighing approximately 20 g, as shown in
7.3.1 Polyoxyethylated Nonylphenol, a stress-cracking Fig. 4. A minimum of 15 containers shall be selected as in 9.1.
agent. See Note 5. The minimum wall thickness of the container shall be not less
D2561 − 17 (2023)
FIG. 3 Bottle Pressure Seal and Tube
NOTE 1—Dimensions are in millimetres with inches in parentheses.
FIG. 4 Standard 473-mL (16-oz) Blown Container
NOTE 8—Test Methods D5947, modified to use a ball tip micrometer,
than 0.305 mm (12 mil). The pinch-off area of the container
can be used to measure the thickness of the container.
shall not extend into the chime radius.
D2561 − 17 (2023)
10. Conditioning 11.2.1 Fill a minimum of 15 containers to one third of
overflow capacity (178 mL) with the stress-cracking solution
10.1 Conditioning—Condition the test specimens at 23 6
described in 7.2.2. Avoid spilli
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