Process for preparing liquophilic polyamide membrane filter media and product
US4340480A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 20, 1980 |
| Grant date | Jul 20, 1982 |
| Priority date | — |
| Expiry date | Oct 20, 2000 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D2325/38
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A process is provided for preparing skinless liquophilic alcohol-insoluble polyamide membranes by preparing at a first temperature a solution in a polyamide solvent having a temperature coefficient of solubility within the range from about 0.01 to about 5 weight percent per degree Centigrade 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 7:1 to about 12:1; 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; cooling the film of casting solution to a second temperature sufficiently lower than the first temperature to precipitate polyamide resin from the casting solution; contacting and diluting the film of casting solution with a nonsolvent liquid, preferably containing a substant…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.