It is a common test method to test the tightness of the packaging material by vacuuming with a vacuum device. This method can be basically used except for packaging materials with larger openings. By vacuuming the vacuum device, the packaging material produces a pressure difference between inside and outside. If the packaging material has poor sealing properties, the water or material contained in the packaging material will overflow from the poorly sealed place.
The method of vacuum test packaging material tightness is to pre-fill the packaging material to be tested with about the actual filling amount of water (for oil products, it must be filled with about the actual filling amount of material body oil), weigh and mark (the reason is the same side ( Inverted) put method), lying down in a vacuum drying box to vacuum, so that it is easy to flow out when water or material leaks.
The two main control indicators of vacuum test are vacuum degree and vacuum time. Each cosmetic factory may be different. The editor used -0.06MPa, 6min. Judging from the multiple test results, the test results using the aforementioned parameters are reliable and accurate. If the vacuum is too high, most of the packaging materials will be unqualified, and the test requirements will be too high; if the vacuum is too low, it will cause the risk of material leakage in the later stage of the qualified packaging materials.
Using a special sealing tester to test, according to the performance of the outer layer material, the negative pressure air tightness test has the following two methods:
1. By evacuating the vacuum chamber to generate a pressure difference between the inside and outside of the sample immersed in water, observe the gas escape from the sample and whether there is continuous bubble generation in the water or water infiltration into the sample to determine the test Kind of sealing performance;
2. By evacuating the vacuum chamber to generate a pressure difference between the inside and outside of the sample, observe the expansion of the sample and the recovery of the sample shape after the vacuum is released to determine the sealing performance of the sample.
Use a special sealing tester to test, pressurize all the samples to be tested or the sealing place to be tested and keep the pressure in the water for an appropriate time to observe whether there is air leakage.