Packages are directly used in liquid package. Since raw material of packages is often processed with high temperature and cooling, some indexes of the raw material cannot indicate the final property of package. That is why various indexes of package should be comprehensively tested.

Being one of the important indexes of flexible package, barrier property directly influences the quality guarantee period of inner content. In fact, except for metal cans and packing box of pulp-molded aluminum, one complete package mainly consists of bottle body and bottle cap. Bottle body is the main test object of barrier property test. However, massive tests have proved that the connecting place of bottle body and bottle cap is a key point influencing barrier property of package. The barrier property test of package should include three parts. Firstly, test barrier property of bottle cap. Next is barrier property testing of bottle cap. The last one is to test barrier property of the connecting place of bottle cap and bottle body. Since bottle cap is often made of metal, it can be considered as possessing high barrier property. Therefore, barrier property testing of package can be divided into the test of bottle body and the test of bottle cap and connecting place.