Nonwoven webs of microporous fibers and filaments
US5230949A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 20, 1991 |
| Grant date | Jul 27, 1993 |
| Priority date | — |
| Expiry date | Jun 20, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T442/696
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
Fibers and filaments of an ultra-high-molecular-weight polyolefin that have a void volume greater than about 20% and are wettable. Wettability is imparted to the fibers and filaments by incorporating a filler into the composition that is hygroscopic, has a particle size less than about 10 microns in diameter and a surface area greater than about 30 square meters per gram. The preferred fillers are those that contain surface silanol groups. The fibers and filaments are formed by the process of preparing a mixture of an ultra-high-molecular-weight polyolefin, filler and plasticizer, metering the mixture to an extruder, heating and kneading the blend in the extruder, conveying the extrudate to a fiber or filament forming type die, expressing the extrudate through the die openings to form fibers or filaments, and extracting at least a portion of the extractable plasticizer to provide the desired porosity. The fibers and filaments may be formed into nonwoven webs directly by the melt blown or spun bonded process or by airlaying or wetlaying techniques. Such webs are particularly useful as a battery separator. The filaments may also be woven into fabric.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.