04340479 is referenced by 253 patents and cites 6 patents.

A process is provided for preparing skinless hydrophilic alcohol-insoluble polyamide membranes by preparing a solution in a polyamide solvent of an alcohol-insoluble polyamide resin having a ratio CH.sub.2 :NHCO of methylene CH.sub.2 to amide NHCO groups within the range from about 5:1 to about 7:1 inducing nucleation of the solution by controlled addition to the solution of a nonsolvent for the polyamide resin, under controlled conditions of concentration, temperature, addition rate, and degree of agitation to obtain a visible precipitate of polyamide resin particles which may or may not thereafter partially or completely redissolve, thereby forming a casting solution; spreading the casting solution on a substrate to form a thin film thereof on the substrate; contacting and diluting the film of casting solution with a mixture of solvent and nonsolvent liquids containing a substantial proportion of the solvent liquid, but less than the proportion in the casting solution, thereby precipitating polyamide resin from the casting solution in the form of a thin skinless hydrophilic membrane; and washing and drying the resulting membrane; the alcohol-insoluble polyamide membranes obtained by this process have the unusual property of being hydrophilic, i.e., readily wetted by water, have absolute particle removal capabilities of the order of 0.1 to 5 .mu.M or more, and are useful as filter media, particularly for producing bacterially sterile filtrates.

Process for preparing hydrophilic polyamide membrane filter media and product
Application Number
Publication Number
Application Date
October 20, 1980
Publication Date
July 20, 1982
David B Pall
Roslyn Estates
Pall Corporation
B01D 31/00
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