Patent ID: 8070999

Claim:
A solution casting process comprising: (A) dissolving a solute in a solvent to prepare a casting solution; (B) placing a membrane-casting plate with an area of â€œSâ€ on a bracket, and adjusting the bracket to make the membrane-casting plate horizontal; (C) pouring the casting solution into the membrane-casting plate such that the casting solution is uniformly spread out in the membrane-casting plate, and a depth of the casting solution is 0.1 to 2 cm; (D) arranging a heating arrangement with an area of â€œaâ€ over the membrane-casting plate with a distance of â€œd 1 â€, a power density of the heating arrangement should be 0.1 to 0.5 W/cm2, and 0.2SÂ½â‰¦d 1 â‰¦0.4SÂ½, 1.2SÂ½â‰¦aÂ½â‰¦2SÂ½; (E) arranging a cooling side plate around the membrane-casting plate with a distance of â€œd 2 â€, arranging a cooling bottom plate below the membrane-casting plate with a distance of â€œd 3 â€, and 0.2SÂ½â‰¦d 2 â‰¦0.4SÂ½, 0.2SÂ½â‰¦d 3 â‰¦0.4SÂ½, supplying a cooling liquor to a connected interlayer of the cooling side plate and the cooling bottom plate, a starting temperature of the cooling liquor is 1 to 50Â° C., a height of the cooling liquor in the interlayer of the cooling side plate is â€œhâ€ and a thickness is â€œvâ€, and 0.2SÂ½â‰¦hâ‰¦0.4SÂ½, 0.05SÂ½â‰¦vâ‰¦0.15SÂ½; (F) enclosing the membrane-casting plate, the bracket, the heating arrangement, the cooling side plate and the cooling bottom plate inside an insulated case made by heat insulator; (G) heating the casting solution in the membrane-casting plate by driving the heating arrangement, the heating temperature should be controlled to be 10 to 30Â° C. lower than a boiling point of the solvent and a heating time should be controlled to be 1 to 10.5 hours, so as to totally evaporate the solvent in the casting solution; (H) when the solvent of the casting solution finishes evaporation, continuously heating for 10 to 200 minutes, to make more solute molecule move and arrange into a crystal lattice and further to improve crystallinity of a final membrane; and (I) stopping heating; removing a condensed solvent from the cooling bottom plate, and peeling the final membrane from the membrane-casting plate after the membrane-casting plate is cooled down.