Patent US3878274A successfully refreshed from Google Patents.
US3878274A
Expired / Lapsed
US
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Process for production of polyvinylidene fluorine resin film
Assignee: Kureha Corp
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Filing: 1972-07-21
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Granted: 1975-04-15
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Expires: 1992-07-21
Abstract
Abstract Polyvinylidene fluoride resin film having outstanding electric characteristics is produced by uniaxially stretching meltextruded polyvinylidene fluoride resin sheet having a birefringent index greater than 1.5 X 10 3 towards a direction which is different from winding direction employed in the extruding operation. The uniaxially stretched film thus obtained is put under direct current electric field of 50KV/cm to 2000KV/cm at temperatures between 40*C and 150*C to thereby impart superior piezoelectric or pyroelectric performances.
Inventors
- 👤 Naohiro Murayama
- 👤 Takao Oikawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:58
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/18; B; B29; B29C; B29C48/00; B29C48/022; G; G01; G01K; G01K7/00; G01K7/003; H; H01; H01B; H01B3/00; H01B3/18; H01B3/30; H01B3/44; H01B3/443; H01B3/445; H01G; H01G4/00; H01G4/002; H01G4/018; H01G4/06; H01G4/14; H01G4/18; H01G4/186; H01G7/00; H01G7/02; H01G7/021; H01G7/023; B29C48/001; B29C48/0018; B29C48/03; B29C48/07; B29C48/08; B29K; B29K2027/00; B29K2027/12; B29K2027/18; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/16
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
69 words
A PROCESS FOR THE PRODUCTION OF A VINYLIDENE FLUORIDE RESIN FILM USEFUL IN ELECTRIC USES, WHICH COMPRISES EXTRUDING AND WINDING A SHEET OF POLYVINYLIDENE FLUORIDE RESIN UNDER CONDITIONS TO PRODUCE AN EXTRUDED SHEET HAVING A BIREFRINGENT INDEX BETWEEN 1.5$10**3 AND 30$10**3 AND THEN UNIAXIALLY STRETCHING SAID EXTRUDED SHEET OF POLYVINYLIDENE FLUORIDE RESIN IN THE DIRECTION WHICH IS 5* TO 90* FROM THE DIRECTION OF WINDING IN THE EXTRUDING STEP.
Claim 2
Dependent Claim
69 words
A PROCESS FOR THE PRODUCTION OF A VINYLIDENE FLUORIDE RESIN FILM USEFUL IN ELECTRIC USES, WHICH COMPRISES EXTRUDING AND WINDING A SHEET OF POLYVINYLIDENE FLUORIDE RESIN UNDER CONDITIONS TO PRODUCE AN EXTRUDED SHEET HAVING A BIREFRINGENT INDEX BETWEEN 1.5$10**3 AND 30$10**3 AND THEN UNIAXIALLY STRETCHING SAID EXTRUDED SHEET OF POLYVINYLIDENE FLUORIDE RESIN IN THE DIRECTION WHICH IS 5* TO 90* FROM THE DIRECTION OF WINDING IN THE EXTRUDING STEP.
Claim 3
Dependent Claim
20 words
The process of claim 1 in which the film is used in a capacitor, piezoelectric element or pyroelectric element film.
Claim 4
Dependent Claim
42 words
A process of claim 1 in which the polyvinylidene fluoride resin is homopolymer of vinylidene fluoride or a copolymer consisting of at least 90% by weight of vinylidene fluoride and at least one of monomers capable of being copolymerized with vinylidene fluoride.
Claim 5
Independent Claim
100 words
A method of producing piezoelectric and pyroelectric polyvinylidene fluoride resin film which comprises extruding and winding a sheet of polyvinylidene fluoride resin under conditions to produce an extruded sheet having a birefringent index between 1.5 X 10 3 and 30 X 10 3 and then uniaxially stretching said extruded sheet of polyvinylidene fluoride resin in a direction which is 5* to 90* from the direction of winding in the extruding step, thereafter applying to the resulted film a direct current electric field of an intensity of 50 KV/cm to 2000 KV/cm while heating at a temperature of 40* to 150*C.
Claim 6
Independent Claim
100 words
A method of producing piezoelectric and pyroelectric polyvinylidene fluoride resin film which comprises extruding and winding a sheet of polyvinylidene fluoride resin under conditions to produce an extruded sheet having a birefringent index between 1.5 X 10 3 and 30 X 10 3 and then uniaxially stretching said extruded sheet of polyvinylidene fluoride resin in a direction which is 5* to 90* from the direction of winding in the extruding step, thereafter applying to the resulted film a direct current electric field of an intensity of 50 KV/cm to 2000 KV/cm while heating at a temperature of 40* to 150*C.
Claim 7
Dependent Claim
20 words
The process of claim 1 wherein the birefringent index of said extruded sheet is up to 20 X 10 3.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-14 | 1978-10-14 | 1979-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-14 | 1982-10-14 | 1983-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-14 | 1986-10-14 | 1987-04-15 | $7700.00 | Window Closed / Lapsed |