1. Anhydrous immersion method
Ziplock bags are generally suitable for packaging where the performance of the outer material will be significantly reduced under the action of water, such as packaging with a paper material for the outer layer.
The sample is filled with test solution (such as a colored aqueous solution with obvious color difference with filter paper). After sealing, place the sample on the filter paper and observe the leakage of the test solution from the inside to the outside. To measure both positive and negative conditions, it can also be placed in a vacuum chamber and tested under negative pressure.
2. Vacuum observation method
Materials suitable for self-sealing bags are the same as above. Through vacuum suction, the internal and external pressure difference of the sample is generated, and the shape recovery of the sample after expansion and vacuum release is observed, so as to determine the sealing performance of the sample.
3. Water pressure
Ziplock bags are usually suitable for packaging where the performance of the outer material does not decrease significantly under the action of water, such as packaging with a plastic film on the outer layer. The vacuum chamber is evacuated to generate the internal and external pressure difference of the sample immersed in water, and the gas escape or water infiltration test is observed to determine the sealing performance of the sample. The most common method for determining sealing performance is the true rate test set.
