Method of manufacturing a cellulose acetate membrane and the membrane so produced
US4744807A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 21, 1986 |
| Grant date | May 17, 1988 |
| Priority date | — |
| Expiry date | Jul 21, 2006 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D2325/022
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A cellulose acetate membrane is provided, capable of separating gaseous hydrogen from a gaseous mixture of hydrogen and hydrocarbon, by casting a 0.02 to 0.05 cm cellulose acetate film into an atmosphere at 20.degree. to 40.degree. C. and a relative humidity of 30 to 70%, from a casting solution at 0.degree. to 20.degree. C. and comprising 10 to 20 wt % cellulose acetate, 60 to 80 wt % acetone, 0.5 to 0.2 wt % magnesium perchlorate, balance water, then evaporating the solvent to form a membrane from the film, then gelling the membrane in ice cold water, then shrinking the membrane at 60.degree. to 90.degree. C. to produce a water wet membrane having an average pore radius less than 7 .ANG., then replacing the water in the membrane sequentially at the laboratory temperature (about 20.degree. to 25.degree. C.) first with aqueous alcohol (isopropyl plus water) and secondly with nonaqueous alcohol (isopropyl), then replacing the alcohol in the membrane with a nonaqueous, readily volatile organic solvent (hexane), and finally evaporating the nonaqueous solvent at laboratory temperature (about 20.degree. to 25.degree. C.) to produce a membrane having a pore radius in the range 1.5 to 5.0…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.