Biaxially oriented microporous membrane
US12179469B2 · kind B2 · utility
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18References
11Claims
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Key dates
| Filing date | Feb 8, 2021 |
| Grant date | Dec 31, 2024 |
| Priority date | — |
| Expiry date | Jul 12, 2043 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/249975
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A microporous membrane is made by a dry-stretch process and has substantially round shaped pores and a ratio of machine direction tensile strength to transverse direction tensile strength in the range of 0.5 to 5.0. The method of making the foregoing microporous membrane includes the steps of: extruding a polymer into a nonporous precursor, and biaxially stretching the nonporous precursor, the biaxial stretching including a machine direction stretching and a transverse direction stretching, the transverse direction stretching including a simultaneous controlled machine direction relax.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.