Method of producing microporous polyolefin membrane
US5786396A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 24, 1997 |
| Grant date | Jul 28, 1998 |
| Priority date | — |
| Expiry date | Jul 24, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02E60/10
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A method of producing a microporous polyolefin membrane having a relatively large pore size and a high permeability, the membrane being suitable for use in water treatment, microfiltration, etc. The method comprises dissolving a polyolefin composition in a solvent to prepare a solution, extruding the solution through a die lip into a form of gel-like sheet, rapidly cooling the gel-like sheet, removing a residual solvent in the cooled sheet by a washing solvent, and drying the resultant sheet to remove the washing solvent. The polyolefin composition is a mixture of (A) an ultra high molecular weight polyolefin having a weight average molecular weight of 5.times.10.sup.5 or more and (B) a polyolefin having a weight average molecular weight less than 5.times.10.sup.5, and a weight ratio of (B)/(A) is 0.2 to 20.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.