The preparation method of mixed cellulose ester sterile filtration membrane mainly includes the following steps:
Raw material preparation: The main raw materials are cellulose ether and cellulose ester, ensuring high purity and no impurities. At the same time, appropriate solvents (such as acetic acid, acetone, etc.), plasticizers (such as TPP and BDP plasticizer mixtures), and stabilizers should be added as needed to ensure that the physical and chemical properties of the film meet the requirements. In addition, UV absorbers, hindered amine light stabilizers, etc. may be added to improve the stability and durability of the membrane.
Solution preparation: Dissolve cellulose ether and cellulose ester in a suitable solvent in a certain proportion to form a uniform polymer solution. Then add plasticizers, stabilizers, and other additives, and mix thoroughly.
Membrane forming: The above solution is made into a thin film by phase separation, immersion, or solvent evaporation methods. This process usually involves coating or soaking a solution onto a supporting material to form a film layer. The formed filter membrane may also need to be stretched and pulled to adjust the thickness and pore size distribution of the membrane.
Drying treatment: After the film layer is formed, it needs to be dried or heated to remove solvents and enhance the mechanical strength of the film.
Surface treatment: In order to improve filtration efficiency and aseptic performance, membrane surfaces may be treated, such as surfactant treatment, antibacterial coatings, etc.
Cutting and embossing: Cut the dried film into the desired size and perform embossing treatment to improve the mechanical strength and filtration performance of the film.
Roll up and packaging: Roll up the processed filter membrane into a roll and pack it aseptically to prevent contamination during transportation and storage. During the packaging process, the membrane should be placed in a sterile environment and subjected to appropriate sterilization treatments such as ultraviolet radiation, gamma rays, or ethylene oxide gas sterilization to ensure the sterility of the filter membrane.