Patent US3110614A successfully refreshed from Google Patents.
US4513049A
Expired / Lapsed
US
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Electret article
Assignee: Mitsui Chemicals Inc
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Filing: 1983-04-26
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Granted: 1985-04-23
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Expires: 2003-04-26
Abstract
Abstract An electret article comprising an even number of electret plastics films laminated together, with the surfaces of the same polarity facing each other, said laminate having the same polarity on both external sides. It keeps its high surface charge density. It will find use in such applications as acoustic materials, filters, and medical supplies.
Inventors
- 👤 Kazuyuki Yamasaki
- 👤 Fukashi Kagawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:18
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/06; B32B27/08; B32B15/00; B32B15/04; B32B15/08; B32B27/12; B32B27/32; B32B27/36; B32B3/00; B32B3/02; B32B3/04; B32B5/00; B32B5/02; B32B5/022; B32B5/024; B32B7/00; B32B7/04; B32B7/12; H; H01; H01G; H01G7/00; H01G7/02; H01G7/021; H01G7/023; H01G7/028; B32B2307/00; B32B2307/10; B32B2307/30; B32B2307/31; Y; Y10; Y10S; Y10S55/00; Y10S55/39; Y10T; Y10T428/00; Y10T428/24; Y10T428/24777; Y10T428/24793; Y10T428/31504; Y10T428/31855; Y10T428/31909; Y10T428/31913; Y10T428/31928
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
70 words
An electret article comprising a laminate of a plurality of electret plastics films, said films being laminated together, the number of films in said plurality of films being an even number, with the juxtaposed internal surfaces of said films facing each other within said laminate being of the same polarity, said laminate having the same polarity on both external surfaces, each of said films having opposite polarities on opposite surfaces.
Claim 2
Dependent Claim
70 words
An electret article comprising a laminate of a plurality of electret plastics films, said films being laminated together, the number of films in said plurality of films being an even number, with the juxtaposed internal surfaces of said films facing each other within said laminate being of the same polarity, said laminate having the same polarity on both external surfaces, each of said films having opposite polarities on opposite surfaces.
Claim 3
Dependent Claim
17 words
An electret article as claimed in claim 1, wherein the edges of the laminate are tightly sealed.
Claim 4
Dependent Claim
16 words
An electret article as claimed in claim 1, wherein the edges of the laminate are heat-sealed.
Claim 5
Dependent Claim
40 words
An electret article as claimed in claim 1, wherein the even number of electret plastics films are laminated together with a spacer in the form of foil, film or sheet being interposed between each pair of juxtaposed electret plastics films.
Claim 6
Dependent Claim
30 words
An electret article as claimed in claim 4, wherein the spacer is one which is selected from a metal foil, plastics film, adhesive, pressure-sensitive adhesive, woven cloth, and non-woven fabric.
Claim 7
Dependent Claim
16 words
An electret article as claimed in claim 1, wherein the plastics film is a polyolefin film.
Claim 8
Dependent Claim
33 words
An electret article as claimed in claim 1, wherein the plastics film is a film of modified polyolefin prepared by graft copolymerization of polyolefin with an unsaturated carboxylic acid or a derivative thereof.
Claim 9
Dependent Claim
40 words
An electret article as claimed in claim 1, wherein the plastics film is a film of a mixture of unmodified polyolefin and a modified polyolefin prepared by graft copolymerization of polyolefin with an unsaturated carboxylic acid or a derivative thereof.
Claim 10
Dependent Claim
16 words
An electret article as claimed in claim 1, wherein the plastics film is a polyester film.
Claim 11
Dependent Claim
18 words
An electret article as claimed in claim 1, wherein the plastics film is a film of fluorocarbon polymer.
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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) | 1988-04-22 | 1988-10-22 | 1989-04-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-04-22 | 1992-10-22 | 1993-04-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-04-22 | 1996-10-22 | 1997-04-23 | $7700.00 | Window Closed / Lapsed |