Sterile barrier performance is lost after use
According to the research, the shelf life of sterile articles is closely related to the thickness and number of layers of non-woven fabrics. After a series of high-temperature steam sterilization and chemical washing, the fiber structure of disposable non-woven packaging materials is deformed, the holes are sparse, the thickness decreases, and even small holes that are not easy to be detected by the naked eye, and the bacteria resistance rate will suddenly decline or lose the bacteria resistance performance. The requirements for packaging materials in the disinfection technical specification are to provide bacterial barrier and maintain sterility during storage. If disposable packaging materials are used repeatedly to package the instrument, the storage after sterilization cannot reach the safe period of validity.
The internal micro properties change after sterilization
Non woven packaging materials are generally SMS composite non-woven fabrics. The main material of this kind of non-woven fabric is polypropylene, which is processed through multiple processes through melt blown and spunbonded processes, and the microstructure is fine plastic fiber (see the figure below). Shrinkage after high temperature is the characteristic of plastic goods. There is no real high-temperature resistant plastic, and high-temperature resistance is also a relative concept. Therefore, non-woven fabrics will also have corresponding shrinkage reaction on the micro level.
After high-temperature sterilization, the fine plastic fiber of the non-woven fabric will shrink to a certain extent. In use, the non-woven fabric after sterilization is more brittle and less flexible than that before sterilization. The change of non-woven packaging materials is one of the reasons why non-woven fabrics can only be used once.