Composite hollow fiber type separation membranes processes for the preparation thereof and their use
US4938778A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 10, 1986 |
| Grant date | Jul 3, 1990 |
| Priority date | — |
| Expiry date | Sep 10, 2006 |
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 24,000x scanning electron microscopy, but which has 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 micro-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.