Extrusion head for forming polymeric hollow fiber
US5318417A · kind A · utility
Inventors
Key dates
| Filing date | Jul 9, 1990 |
| Grant date | Jun 7, 1994 |
| Priority date | — |
| Expiry date | Jul 9, 2010 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2201/052
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A process for making a polymeric, porous hollow fibre (21) by heating a mixture of a thermoplastic polymer and a solvent to a temperature and for a time for the polymer and solvent to mutually dissolve, then introducing the molten mixture into an extrusion head (FIG. 1) adapted to shape the hollow fibre. The shaped fibre is then cooled in the extrusion head to a temperature so that non-equilibrium liquid-liquid phase separation takes place to form a bi-continuous matrix of the polymer and solvent in which the polymer and solvent form two intermingled separate phases of large interfacial surface area. Finally, the solvent is removed from the polymer. The extrusion head for forming the abovementioned polymeric, porous hollow fibre has an elongated body (17, 18) defining an axial passageway (11) for receiving a lumen-forming fluid (14) and a first annular passage (12) therearound for receiving the molten mixture (15) from which the hollow fibre (21) is formed. A second annular passageway (13) is radially outward of the first annular passageway (12) and receives a coating fluid (16). A third annular passageway (19) receives a cooling fluid and has means (20) for directing the cooling f…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.