EP0322169A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Microporous filaments and fibers, process of making same, and articles made therefrom
Assignee: Entek Manufacturing LLC
•
Filing: 1988-12-19
•
Granted: —
•
Expires: 2008-12-19
Abstract
Abstract Fibers and filaments of an ultrahigh 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 forming a mixture of the ultrahigh 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 spinneret-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 woven and nonwoven webs by airlaying and wetlaying techniques. Such webs are particularly useful as a battery separator.
Inventors
- 👤 Robert E. Howard
- 👤 James Young
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 16:17
CPC Classifications
D; D01; D01D; D01D5/00; D01D5/24; D01D5/247; H; H01; H01M; H01M50/00; H01M50/40; H01M50/409; H01M50/411; H01M50/414; H01M50/417; D01F; D01F6/00; D01F6/02; D01F6/04; H01M50/429; H01M50/489; H01M50/491; Y; Y02; Y02E; Y02E60/00; Y02E60/10
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
93 words
A strand-like article comprised of about 10% to about 90% by volume of an ultra high molecular weight polyolefin selected from the group consisting of homopolymers and copolymers of ethylene, propylene and butylene; about 10% to about 90% by volume of a hygroscopic filler having a particle size less than about 10 microns and a surface area greater than about 30 m²/gram; and about 1% to about 15% by volume of a plasticizer having a solubility parameter between about 7.3 and about 8.4; said article having a void volume greater than about 20%.
Claim 2
Dependent Claim
93 words
A strand-like article comprised of about 10% to about 90% by volume of an ultra high molecular weight polyolefin selected from the group consisting of homopolymers and copolymers of ethylene, propylene and butylene; about 10% to about 90% by volume of a hygroscopic filler having a particle size less than about 10 microns and a surface area greater than about 30 m²/gram; and about 1% to about 15% by volume of a plasticizer having a solubility parameter between about 7.3 and about 8.4; said article having a void volume greater than about 20%.
Claim 3
Dependent Claim
15 words
The article of claim 1 wherein the filler is a material having surface silanol groups.
Claim 4
Dependent Claim
10 words
The article of claim 2 wherein the filler is silica.
Claim 5
Dependent Claim
19 words
The article of claim 1 wherein the polyolefin is polyethylene having an inherent viscosity greater than about 5 dl/gram.
Claim 6
Dependent Claim
13 words
The article of claim 1 wherein the plasticizer is a petroleum hydrocarbon oil.
Claim 7
Dependent Claim
33 words
A nonwoven web formed of a multiplicity of the strand-like articles of claim 1, said web having a macroporosity greater than about 50% and a maximum macropore size less than about 25 microns.
Claim 8
Dependent Claim
16 words
A waterlaid paper web formed of a multiplicity of the strand like articles of claim 1.
Claim 9
Dependent Claim
9 words
The paper web of claim 1 containing cellulosic fibers.
Claim 10
Dependent Claim
14 words
A woven fabric formed of a multiplicity of the strand-like articles of claim 1.
Claim 11
Dependent Claim
47 words
A battery separator comprised of a web formed of a multiplicity of the strand-like articles of claim 1, said web having a thickness of between about 1 and about 100 mils and an electrical resistance of less than about 1.5 milliohms per square inch per mil thickness.
Claim 12
Dependent Claim
124 words
A process of forming microporous strand-like articles which are wettable comprising forming a mixture of an ultra high molecular weight polyolefin and a hygroscopic filler having a particle size less than about 10 microns and a surface area greater than about 30 m²/gram; feeding the mixture and a plasticizer having a solubility parameter between about 7.3 and about 8.4 to the feed port of an extruder; heating and mixing the blend of the mixture and plasticizer in the extruder at a temperature sufficient to plasticate the blend; feeding the extrudate from the extruder to a die suitable for forming strand-like articles; expressing strand-like articles from the die; and extracting sufficient plasticizer from the strand-like articles to achieve a void volume greater than about 20%.
Claim 13
Dependent Claim
124 words
A process of forming microporous strand-like articles which are wettable comprising forming a mixture of an ultra high molecular weight polyolefin and a hygroscopic filler having a particle size less than about 10 microns and a surface area greater than about 30 m²/gram; feeding the mixture and a plasticizer having a solubility parameter between about 7.3 and about 8.4 to the feed port of an extruder; heating and mixing the blend of the mixture and plasticizer in the extruder at a temperature sufficient to plasticate the blend; feeding the extrudate from the extruder to a die suitable for forming strand-like articles; expressing strand-like articles from the die; and extracting sufficient plasticizer from the strand-like articles to achieve a void volume greater than about 20%.
Claim 14
Dependent Claim
13 words
The process of claim 11 wherein the strand-like articles are attenuated after extraction.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.