Significance and Use
These procedures provide an indication of the environmental stress-crack resistance of injection molded open head pails, covers, and components from a selected group or lot. Provided the thermal history of each container is constant, this test method may be used for determining the applicability of various plastic resins and mold designs for injection molding of open head pails and covers.
The environmental stress-crack that occurs is indicative of what results when a container is exposed to agents such as soaps, organics, or any surface active solutions while under environmental conditions of stress.
Environmental stress-cracking is the mechanism of chemical attack that is highly dependent upon the test reagent, resin, container molding history, exposure temperature, applied stress, and other factors. The combination of these factors may result in eventual stress-crack failure.
Procedure A minimizes the potential for test variability by providing the user with rigidly defined test conditions. This test method may be used for production quality control of injection molded open head containers.
Procedure B allows the user to select and evaluate extreme individual elements or the interaction of several test levels on container performance. These conditions are established based on laboratory experience and available knowledge of the distribution environment. This test method may be used for identifying critical stresses which could aid in container design or help in minimizing the occurrence of these stresses during distribution.
This test method is intended only as a pass/fail procedure in accordance with the user's specification, or as agreed upon between the user and the supplier. It is not intended as a predictor or indicator of field performance regarding time to failure.
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 standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
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, 10.2.4, 10.2.6, and 10.2.8.