Porous membrane and method for preparing the same
US5202025A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 14, 1992 |
| Grant date | Apr 13, 1993 |
| Priority date | — |
| Expiry date | Jan 14, 2012 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D2325/36
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
In the method for preparing a porous membrane, a polymer having a low glass transition temperature is held on the surface of a porous membrane substrate and then drawing is conducted. Accordingly, the drawing at a high draw ratio can be conducted to which the substrate as such can not be subjected. As a result, not only an excellent porous membrane having an enlarged pore size and an increased void volume can be obtained but also it is possible to control the pore size and the void volume in wide ranges. Further, a hydrophilic polymer having a glass transition temperature of not more than 300 K is formed on the surface of pores of a porous membrane substrate by graft polymerization so as to bond the hydrophilic polymer on the substrate by a covalent bond. Therefore, it is possible to provide a porous membrane excellent in unbrittleness and inhibiting elution in an environmental liquid or the like.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.