The difference between hollow fiber composite membranes and wet laid membranes:
1. Hollow fiber membranes refer to membranes that are fibrous in appearance and self-supporting. Hollow fiber membranes are made of polysulfone and dimethylacetamide as raw materials, processed into fiber filaments with a hollow internal cavity, and then divided into high-permeability polymers, which have selective permeability characteristics. Since water vapor, hydrogen, ammonia, and carbon dioxide penetrate quickly, while methane, nitrogen, argon, oxygen, and carbon monoxide penetrate slowly, this separates those who penetrate quickly from those who penetrate slowly. The outer diameter of hollow fiber filament is generally 500-600 pum, and the inner diameter is 200-300 pum. It is made into a fiber bundle of 3 to 6 meters and packed in a shell mmetal resistant to high pressures. The fiber bundle is sealed and the other end is coated with a specially formulated epoxy resin.
2. Lithium battery separators are generally divided into dry process and wet process according to the process. Therefore, separation products are also divided into dry process and wet process separators. The wet process mixes liquid hydrocarbons or certain small molecular substances with a polyolefin resin, heats and melts them to form a uniform mixture, then cools to perform phase separation and pressing to obtain a diaphragm. The diaphragm is then heated to a temperature close to . the melting point and biaxial stretching to give the chain orientation of molecules, and finally maintain the temperature for a certain period of time, and use volatile substances to elute the remaining solvent, pcan prepare interconnected microporous membrane materials. Since the process requires the use of paraffin oil mixed with PE to create holes and solvent extraction is required to remove it after the stretching process, the process is called wet method. Wet process technology is mainly used in the manufacturing of polyethylene separators.