D5419- 09 Standard Test Method for Environmental Stress Crack Resistance (ESCR) of Threaded Plastic Closures
Significance and Use
This test method compares
closures for ESCR. Suitable variables are: closure materials, closure
designs, processes, applied torque, and stress-crack agents.
Results
can be used for estimating shelf life of closures in terms of ESCR.
This requires that the user has calibrated failure time in this test to
failure time in the field for actual packaging systems.
1. Scope
1.1
This test method determines the susceptibility of threaded plastic
closures to failure due to environmental stress cracking (ESC).
1.2
In use, threaded plastic closures can contact agents that appreciably
reduce the stress at which cracks form. Examples of such agents are:
soaps, detergents, oils, and liquid bleaches.
1.3
Major factors that influence environmental stress crack resistance
(ESCR) of threaded plastic closures include the closure material(s),
closure design, molded-in stress, and applied stress.
1.4
This procedure can be applied to all closures, but is particularly
applicable to closures made from plastics based on polypropylene (PP)
or polystyrene (PS).
1.5 The values stated in SI units are to be regarded as the standard.
1.6 This
standard does not purport to address all of the safety concerns, 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 precautionary statements are given in Section 8 and 6.2. Note 1—There is no known ISO equivalent to this test method.
2. Referenced Documents
ASTM Standards
D1600 Terminology for Abbreviated Terms Relating to Plastics
D2911 Specification for Dimensions and Tolerances for Plastic Bottles
D3198 Test Method for Application and Removal Torque of Threaded or Lug-Style Closures
D618 Practice for Conditioning Plastics for Testing
D883 Terminology Relating to Plastics
E145 Specification for Gravity-Convection and Forced-Ventilation Ovens
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
Index Terms
closures; environmental stress crack resistance (ESCR); failure;
plastic; stress crack; threaded plastic closures; Closures (threaded);
Environmental stress crack resistance (ESCR); Failure end
point--plastics; Polypropylene (PP); Polystyrene (PS);
Stress--plastics; Threaded closures
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