Method for preparing oriented microporous film
US5238618A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 30, 1991 |
| Grant date | Aug 24, 1993 |
| Priority date | — |
| Expiry date | Aug 30, 2011 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2201/052
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A method for preparing an oriented microporous shaped article is provided. The method comprises the steps of melt blending thermoplastic polymer with a solubilizing amount of a compatible liquid to form a homogeneous solution, forming a shaped article from the solution, cooling the shaped article at a rate and to a temperature sufficient to initiate thermodynamic, non-equilibrium liquid-liquid phase separation and then to solidify the thermoplastic polymer, stretching the article in a first direction sufficient to permanently attenuate the article and effect orientation of the polymer, and removing at least a substantial portion of the compatible liquid before or after the stretching step to form an oriented microporous shaped article.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.