According to research, the shelf life of sterile items is closely related to the thickness of the non-woven fabric and the number of layers of wrapping cloth. After a series of high-temperature steam sterilization and chemical washing of disposable non-woven packaging materials, the fiber structure is deformed, the holes are sparse, the thickness is reduced, and even small holes that are not easily detectable by the naked eye appear, the bacteria resistance rate will drop suddenly or Loss of bacteriostatic properties.
The requirements for packaging materials in the "Technical Specification for Disinfection" are: in the storage process, provide a bacterial barrier and maintain a sterile state. If the disposable packaging material is reused to wrap the device, the sterilized storage cannot reach the safe expiration date.
Non-woven packaging materials are generally composite non-woven surgical fabrics. The main material of this type of non-woven fabric is polypropylene, which is processed through multiple processes through meltblown and spunbond processes, and the microstructure is fine plastic fibers.
Shrinkage after being exposed to high temperature is a characteristic of plastic items. There is no real high temperature resistant plastic, and high temperature resistance is also a relative concept. Therefore, non-woven surgical fabrics will also have corresponding shrinkage reactions on the microscopic level.
After high temperature sterilization, the fine plastic fibers of the non-woven fabric will shrink to a certain extent, and the performance is that the non-woven polyethylene fabric after sterilization is 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.