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US5496507A
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Method of charging electret filter media
Assignee: 3M Co
•
Filing: 1994-08-17
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Granted: 1996-03-05
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Expires: 2014-08-17
Abstract
Abstract A method of charging a nonwoven web of thermoplastic microfibers to provide electret filter media is provided. The method includes impinging on a nonwoven web of thermoplastic nonconductive microfibers capable of having a high quantity of trapped charge jets of water or a stream of water droplets at a pressure sufficient to provide the web with filtration enhancing electret charge and drying said web.
Inventors
- 👤 Seyed A. Angadjivand
- 👤 Marvin E. Jones
- 👤 Daniel E. Meyer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:20
CPC Classifications
D; D06; D06M; D06M11/00; D06M11/01; D06M11/05; B; B01; B01D; B01D39/00; B01D39/08; B01D39/14; B01D39/16; B01D39/1607; B01D39/1623; D04; D04H; D04H1/00; D04H1/40; D04H1/407; D04H1/42; D04H1/4282; D04H1/4291; D04H1/4382; D04H1/43825; D04H1/43828; D04H1/43835; D04H1/43838; D04H1/44; D04H1/46; D04H1/492; D04H1/54; D04H1/56; D06M10/00; D06M10/02; D06M10/025; A; A62; A62B; A62B23/00; A62B23/02; A62B23/025; B01D2239/00; B01D2239/02; B01D2239/0216; B01D2239/0225; B01D2239/0233; B01D2239/04; B01D2239/0407; B01D2239/0435; B01D2239/06; B01D2239/0604; B01D2239/0618; B01D2239/0622; B01D2239/064; B01D2239/065; B01D2239/0654; B01D2239/0663; B01D2239/069; B01D2239/10; B01D2239/12; B01D2239/1233; B01D2239/1291; D06M2101/00; D06M2101/16; D06M2101/18; Y; Y10; Y10S; Y10S264/00; Y10S264/48; Y10S55/00; Y10S55/05; Y10S55/35; Y10S55/39; Y10T; Y10T442/00; Y10T442/60; Y10T442/608; Y10T442/614; Y10T442/626
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
74 words
A method of charging a nonwoven web of thermoplastic microfibers to provide electret filter media comprising (1) impinging on a nonwoven web of thermoplastic nonconductive microfibers which have a resistivity greater than 10 16 ohm cm and are capable of having a high quantity of trapped charge, jets of water or a stream of water droplets at a pressure sufficient to provide the web with filtration enhancing electret charge and (2) drying said web.
Claim 2
Independent Claim
74 words
A method of charging a nonwoven web of thermoplastic microfibers to provide electret filter media comprising (1) impinging on a nonwoven web of thermoplastic nonconductive microfibers which have a resistivity greater than 10 16 ohm cm and are capable of having a high quantity of trapped charge, jets of water or a stream of water droplets at a pressure sufficient to provide the web with filtration enhancing electret charge and (2) drying said web.
Claim 3
Dependent Claim
16 words
The method of claim 1 wherein said jets of water are provided by a hydroentangling device.
Claim 4
Dependent Claim
16 words
The method of claim 1 wherein said stream of water droplets is provided by a nebulizer.
Claim 5
Dependent Claim
29 words
The method of claim 1 wherein said jets of water or stream of water droplets is provided at a pressure in the range of about 69 to 3450 kPa.
Claim 6
Dependent Claim
28 words
The method of claim 1 wherein said web is subjected to corona discharge treatment prior to impingement of said jets of water or said stream of water droplets.
Claim 7
Dependent Claim
12 words
The method of claim 1 wherein said web further contains staple fiber.
Claim 8
Dependent Claim
18 words
The method of claim 6 wherein said staple fiber comprises up to 90 weight percent of said web.
Claim 9
Dependent Claim
20 words
The method of claim 1 wherein said web has a basis weight of about 5 to 500 g/m 2 .
Claim 10
Dependent Claim
17 words
The method of claim 1 wherein said web has a thickness of about 0.25 to 20 mm.
Claim 11
Dependent Claim
19 words
The method of claim 1 wherein said microfibers have an effective fiber diameter of about 3 to 30 μm.
Claim 12
Dependent Claim
14 words
The method of claim 1 wherein said microfibers are polypropylene, poly(4-methyl-1-pentene) or blends thereof.
Claim 13
Dependent Claim
12 words
The method of claim 1 wherein said microfibers comprise polypropylene and poly(4-methyl-1-pentene).
Claim 14
Dependent Claim
15 words
The method of claim 12 wherein the polypropylene and poly(4-methyl-1-pentene) are layered in said microfibers.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-03-05 | 1999-09-04 | 2000-03-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-03-05 | 2003-09-04 | 2004-03-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-03-05 | 2007-09-04 | 2008-03-05 | $7700.00 | Window Closed / Lapsed |