ASTM D1975-95
(Test Method)Standard Test Method for Environmental Stress Crack Resistance of Plastic Injection Molded Open Head Pails
Standard Test Method for Environmental Stress Crack Resistance of Plastic Injection Molded Open Head Pails
SCOPE
1.1 This test method provides procedures for an indication of the environmental stress crack resistance of plastic injection molded open head pails, covers, and components as a summation of the effects of container design, resin, manufacturing conditions, field performance, and other factors.
1.2 This test method may be used to evaluate a container's resistance to mechanical failure by cracking when in the presence of chemical and physical stresses.
1.3 Two procedures are provided as follows:
1.3.1 Procedure A, Specified Stress-Crack Resistance Test Method—This procedure is particularly useful for quality control since the conditions of the test are specified.
1.3.2 Procedure B, User Selected Stress-Crack Resistance Test Method—This procedure allows individual selection of test levels and is particularly useful as a design and development tool.
1.4 These procedures are not designed to test the ability of the cover gasketing material or closure to retain the test reagent. Loss or leakage of the reagent through these openings does not constitute container failure. However, this may indicate an internal pressure loss that might affect test results.
1.5 The values stated in inch-pound units are to be regarded as the standard. The SI units given in parentheses are for information only.
1.6 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific warning statements are given in 6.2, 10.2.3, 10.2.6, and 10.2.8.
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NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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Designation: D 1975 – 95
Standard Test Method for
Environmental Stress Crack Resistance of Plastic Injection
Molded Open Head Pails
This standard is issued under the fixed designation D 1975; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope Package Components for Testing
E 122 Practice for Choice of Sample Size to Estimate a
1.1 This test method provides procedures for an indication
Measure of Quality for a Lot or Process
of the environmental stress crack resistance of plastic injection
molded open head pails, covers, and components as a summa-
3. Terminology
tion of the effects of container design, resin, manufacturing
3.1 Definitions—Reference Terminology D 996 for defini-
conditions, field performance, and other factors.
tions applicable to this test method.
1.2 This test method may be used to evaluate a container’s
3.2 Definitions of Terms Specific to This Standard:
resistance to mechanical failure by cracking when in the
3.2.1 environmental stress crack—an external or internal
presence of chemical and physical stresses.
crack that develops when a container is exposed to chemical or
1.3 Two procedures are provided as follows:
physical stresses, or both.
1.3.1 Procedure A, Specified Stress-Crack Resistance Test
3.2.2 stress crack failure—any environmental stress crack
Method—This procedure is particularly useful for quality
that causes a loss or leakage of the test reagent shall be
control since the conditions of the test are specified.
interpreted as container failure.
1.3.2 Procedure B, User Selected Stress-Crack Resistance
Test Method—This procedure allows individual selection of
4. Summary of Test Method
test levels and is particularly useful as a design and develop-
4.1 The environmental stress-crack resistance is determined
ment tool.
by subjecting an injection molded open head pail and cover
1.4 These procedures are not designed to test the ability of
that is filled and sealed with a stress-crack reagent to a
the cover gasketing material or closure to retain the test
mechanical top load at elevated temperatures. The time to
reagent. Loss or leakage of the reagent through these openings
stress-crack failure is observed.
does not constitute container failure. However, this may
4.1.1 Procedure A exposes a minimum of three containers to
indicate an internal pressure loss that might affect test results.
specified levels of chemical and physical stresses.
1.5 The values stated in inch-pound units are to be regarded
4.1.2 Procedure B exposes containers to varying chemical
as the standard. The SI units given in parentheses are for
and physical stresses based on the user’s knowledge and
information only.
objectives.
1.6 This standard does not purport to address all of the
safety problems, if any, associated with its use. It is the
5. Significance and Use
responsibility of the user of this standard to establish appro-
5.1 These procedures provide an indication of the environ-
priate safety and health practices and determine the applica-
mental stress-crack resistance of injection molded open head
bility of regulatory limitations prior to use. Specific caution
pails, covers, and components from a selected group or lot.
statements are given in Note 1, Note 4, Note 6, Note 10, and
Provided the thermal history of each container is constant, this
Note 12.
test method may be used for determining the applicability of
various plastic resins and mold designs for injection molding of
2. Referenced Documents
open head pails and covers.
2.1 ASTM Standards:
5.2 The environmental stress-crack that occurs is indicative
D 996 Terminology of Packaging and Distribution Environ-
2 of what results when a container is exposed to agents such as
ments
soaps, organics, or any surface active solutions while under
D 4332 Practice for Conditioning Containers, Packages, or
environmental conditions of stress.
5.3 Environmental stress-cracking is the mechanism of
This test method is under the jurisdiction of ASTM Committee D-10 on
chemical attack that is highly dependent upon the test reagent,
Packaging and is the direct responsibility of Subcommittee D10.23 on Storage Test
resin, container molding history, exposure temperature, applied
Methods.
Current edition approved Sept. 10, 1995. Published November 1995. Originally
published as D 1975 – 91. Last previous edition D 1975 – 91.
2 3
Annual Book of ASTM Standards, Vol 15.09. Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 1975
stress, and other factors. The combination of these factors may 9. Conditioning
result in eventual stress-crack failure.
9.1 Condition empty test containers at 73 6 2°F (23 6
5.4 Procedure A minimizes the potential for test variability
1.3°C) 506 3 % relative humidity for 48 h prior to testing (see
by providing the user with rigidly defined test conditions. This
Practice D 4332).
test method may be used for production quality control of
10. Procedure
injection molded open head containers.
5.5 Procedure B allows the user to select and evaluate
10.1 Procedure A—Specified Stress-Crack Resistance
extreme individual elements or the interaction of several test
Method:
levels on container performance. These conditions are estab-
10.1.1 Place the oven set point control at 122 6 2°F (50 6
lished based on laboratory experience and available knowledge
1.3°C) and allow it to reach equilibrium. Fill each test
of the distribution environment. This test method may be used
specimen to 98 % of the container’s total volumetric capacity
for identifying critical stresses which could aid in container
with the test reagent. Apply the cover to the pail firmly and
design or help in minimizing the occurrence of these stresses
evenly using a method similar to the assembly technique used
during distribution.
during actual production.
5.6 This test method is intended only as a pass/fail proce-
10.1.2 Place test specimens in the oven on an even horizon-
dure in accordance with the user’s specification, or as agreed
tal surface. Place an identical pail filled to rated capacity with
upon between the user and the supplier. It is not intended as a
sand or water on top of each test specimen. Apply additional
predictor or indicator of field performance regarding time to
weight to the top of the pail filled with sand or water to bring
failure.
the total top load weight (sand or water pail plus weight) up to
the values specified in Table 1. Record the time and date the
6. Apparatus
test was started.
6.1 Oven—The oven should be capable of maintaining a
10.1.3 Inspect the test pails and covers daily for any
temperature control of 62.5°F (61.4°C) of set point. For best
evidence of stress-crack failure. Inspection is performed with-
circulation and a constant temperature throughout, a forced air
out removing the top load from the test container. Stress crack
system is recommended.
may be more easily detected by placing the pail on top of a
6.2 Top Load—Requires a pail identical to the test pail be
moisture indicating medium, such as paper. The moisture
filled to rated capacity or weight and then nested above the test
indicating medium will allow the detection of small leaks that
pail. Free weights are then placed above in amounts necessary
otherwise may evaporate. Record the time, date, and location
to equal the specified top load. A calibrated pneumatic or
of any failure that occurs.
hydraulic cylinder may be substituted for the additional free
10.2 Procedure B—User Selected Stress-Crack Resistance
weights.
Method:
10.2.1 The following are individual elements that may
NOTE 1—Caution: The potential exists for catastrophic stress-crack
failure causing an instability of the applied top load. Precautionary steps attribute to the weakening of a polymer and eventual stress-
should be taken (that is, through restraining or guiding of the top load) to
crack failure. Use these guidelines in establishing and selecting
reduce the chance for injury to the operators or dama
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