然而塑料软包装材料主体结构是塑料聚合物，对气体有一定的渗透性，因此并不能完全代替金属、玻璃包装。

However, the main structure of plastic flexible packaging materials are plastic polymers, has some permeability to gas, and therefore can not fully replace the metal and glass packaging.

youdao

然而塑料软包装材料主体结构是塑料聚合物，对气体有一定的渗透性，因此并不能完全代替金属、玻璃包装。

However, the main structure of plastic flexible packaging materials are plastic polymers, has some permeability to gas, and therefore can not fully replace the metal and glass packaging.

youdao