Flexible packaging products refer to the use of soft materials such as high-barrier plastic films or metal foils and their composite films to make bags or other shapes of containers. To commercial aseptic, packaged food that can be stored at room temperature. The processing principle and art method are similar to metal cans for storing food. Common packaging containers include plastic cups and plastic bottles. Cooking bags, boxes, etc.
Because the allowable critical pressure difference of the flexible packaging material is particularly small, the pressure in the container during the sterilization process is very easy to burst after the temperature rises. The characteristic of the cooking bag is that it is afraid of rising and not pressure; and plastic cups and bottles are both afraid of rising and pressure, so it is necessary to use a reverse pressure sterilization process in sterilization. This process determines that the sterilization temperature and mortar pressure need to be controlled separately in the production of flexible packaging The sterilization equipment, such as full water type (water bath type), water spray type (top spray, side spray, full spray), steam and air mixing type sterilization, generally set various parameters by PLC for automatic control.
It should be emphasized that the four elements of the metal can sterilization process control (initial temperature, sterilization temperature, time, key factors) are also applicable to the sterilization control of flexible packaged food, and the pressure during the sterilization and cooling process must be strictly controlled.
Some companies use steam sterilization for flexible packaging sterilization. In order to prevent the cooking bag from bursting, simply input compressed air into the steam sterilization pot to apply a back pressure excitation to the packaging bag. This is a scientifically wrong practice. Because steam sterilization is carried out under pure steam conditions, if there is air in the pot, an air bag will be formed, and this air mass will travel in the sterilization pot to form some cold areas or cold spots, which makes the sterilization temperature uneven, resulting in Insufficient sterilization of some products. If you must add compressed air, you need to be equipped with a powerful fan, and the power of this fan is carefully designed to allow compressed air to be forcedly circulated by the high-power fan immediately after entering the pot. The air and steam flow are mixed, In order to ensure that the temperature in the sterilization pot is uniform, to ensure the product sterilization effect.