Composite hollow fiber-type separation membranes, processes for the preparation thereof and their use
US4664669A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 28, 1984 |
| Grant date | May 12, 1987 |
| Priority date | — |
| Expiry date | Feb 28, 2004 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/249953
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A composite hollow fiber type separation membrane which has three layers comprising a selective separation layer, an ultra-microporous layer and a porous layer, said selective separation layer, said ultra-microporous layer, said porous layer being arranged in said order commencing from the inner surface of said hollow fiber membrane; PA1 wherein said selective separation layer is formed on said ultra-microporous layer without penetrating into said ultra-microporous layer and has a non-porous, dense structure, the average thickness of said layer being 0.01-2.mu., and the coefficient of variation in thickness thereof being less than or equal to 25%; PA1 wherein said ultra-microporous layer has a surface in which the presence of pores cannot be confirmed by 24,000 .times. scanning electron microscopy, but which has a fluid permeability at least 10 times that of said selective separation layer, the thickness of said layer being less than or equal to 0.08.mu.; and PA1 wherein said porous layer is a sponge structure comprising pores having a pore diameter of 0.1-1.mu. except for macro-voids and having a porosity of at least 50%, the thickness of said layer being 10-500.mu..
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.