This part of YY/T 0681 specifies the materials and a procedure that will detect and locate a leak equal or greater than a channel formed by a 50 μm wire in package edge seals formed between a transparent film and a porous material. A dye penetrant is applied locally to the seal edge to be tested for leaks. After contact with the dye penetrant for a specified time, the package is visually inspected for dye penetration.
This test method is intended for use on packages with edge seals formed between a transparent film and a porous material. This test method is limited to porous materials which can retain the dye penetrant and prevent it from discoloring the entire seal area for a minimum of 20 s. Uncoated papers are especially susceptible to leakage and must be evaluated carefully for use with this test method.
This test method requires that the dye penetrant have good contrast to the opaque packaging material.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1
wicking
the migration of a liquid into the body of a fibrous material
2.2
dye penetrant
an aqueous solution of a coloring agent and a surfactant designed to penetrate and indicate a defect location in the time prior to the onset of wicking (which could mask its presence)
2.3
channel
a small continuous open passage across the width of a package seal through which microorganisms could pass it is the objective of this test method to visually observe the presence of these defects by the leakage of dye through them
3 Significance and use
3.1 Harmful microorganism or particulate contaminants may enter the device through leaks. These leaks are frequently found at seals between package components of the same or dissimilar materials. Leaks may also result from a pinhole in the packaging material.
3.2 This dye penetrant procedure is applicable only to individual leaks in a package seal, not to a number of small leaks found in porous packaging material, which need to be detected by other techniques.
3.3 There is no general agreement concerning the level of leakage that is likely to be deleterious to a particular package. However, since this test is designed to detect leakage, components that exhibit any indication of leakage are normally rejected.
3.4 Since leaks may change in size with different ambient conditions, comparisons between test stations are not conclusive. Therefore this method is usually employed as a pass and rejected test.
