Patent WO-2023068433-A1 (WO)
Title: Pvdf composite separation membrane manufacturing method, and pvdf composite separation membrane manufactured using same
Inventor: OH SOON BONG
IPC: B01D65/08
Filed: 2021-11-18
Abstract: The present invention relates to a polyvinylidene fluoride (PVDF) composite separation membrane manufacturing method, and a PVDF composite separation membrane manufactured using same, and the PVDF composite separation membrane manufacturing method comprises the steps of: mixing, with 65-95 parts by weight of a solvent, 0.1-10 parts by weight of one or more carbon structures selected from the group, which consists of carbon nanotubes and reduced graphene or graphene oxide containing a carboxyl group or a hydroxyl group, and 0.1-12 parts by weight of titanium oxide, and dispersing same through ultrasonication, thereby obtaining a first solution; mixing, with the first solution, 1-18 parts by weight of a first pore control agent, which contains a polyethylene glycol (PEG) having a molecular weight of 190-610, and 1-22 parts by weight of a second pore control agent, which contains a polyvinyl pyrrolidone (PVP) having a weight average molecular weight of 8,000-900,000, and stirring same at a temperature of 70-90°C, thereby obtaining a second solution; mixing 21-38 parts by weight of a PVDF polymer with the second solution, and stirring same at a temperature of 70-90°C, thereby obtaining a third solution; forming a film from the third solution on the other surface of a mesh, which has release paper provided on one surface thereof and has a pore size of 25-400 μm, and then casting same to have a thickness of 20-600 μm, thereby obtaining a primary film composite separation membrane; performing primary phase transition on the primary film composite separation membrane in an alcohol; performing, in distilled water, secondary phase transition on the primary film composite separation membrane having undergone primary phase transition; removing the release paper, and then washing the primary film composite separation membrane; drying the washed primary film composite separation membrane at a temperature of 80-120°C; firing the dried primary film composite separation membrane in an atmospheric furnace at a temperature of 180-220°C, so as to melt-bond, to the mesh, the PVDF of the primary film composite separation membrane, and then cooling same; forming a film of the third solution on the one surface of the mesh of the cooled primary film composite separation membrane, from which the release paper has been removed, and then casting same to have a thickness of 20-600 μm, thereby obtaining a secondary film composite separation membrane; performing primary phase transition on the secondary film composite separation membrane in an alcohol; performing, in distilled water, secondary phase transition of the secondary film composite separation membrane having undergone primary phase transition; washing the secondary film composite separation membrane; drying the washed secondary film composite separation membrane at a temperature of 80-120°C; and firing the dried secondary film composite separation membrane in an atmospheric furnace at a temperature of 230-290°C, so as to melt-bond, to the mesh, the PVDF of the secondary film composite separation membrane, and then cooling same.