Patent US4290983A successfully refreshed from Google Patents.
US4290983A
Expired / Lapsed
US
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Piezoelectric and pyroelectric film and method for preparing the film
Assignee: Kureha Corp
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Filing: 1979-11-19
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Granted: 1981-09-22
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Expires: 1999-11-19
Abstract
Abstract A piezoelectric and pyroelectric film made from a resin composition of polymer of vinylidene fluoride, which is characterized by an index of birefringence of larger than 3×10 -3 and a ratio of d 31 /d 32 of 0.3 to 3.0, and which may be prepared by further stretching a biaxially stretched film made from the above-mentioned resin composition at a temperature lower than the temperature of the biaxially stretching by more than 20° C. before or at the same time of a treatment for orientation polarization of the film.
Inventors
- 👤 Tohru Sasaki
- 👤 Syuuzi Terasaki
- 👤 Tomoo Susa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 04:12
CPC Classifications
H; H10; H10N; H10N15/00; H10N15/10; H10N30/00; H10N30/01; H10N30/04; H10N30/045; H10N30/09; H10N30/098; H10N30/80; H10N30/85; H10N30/857; Y; Y10; Y10T; Y10T29/00; Y10T29/42
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
95 words
A method for preparing a piezoelectric and pyroelectric film comprising the steps of, biaxially stretching a film made from a resin composition of a polymer of vinylidene fluoride; additionally stretching the thus obtained biaxially stretched film at a temperature of lower than the crystallizing temperature of said resin composition, which additional stretching temperature is lower than the temperature at the biaxially stretching by more than 20° C. and is higher than the secondary transition temperature of said resin composition; and at the same time or after the additional stretching polarizing the thus additionally stretched film
Claim 2
Independent Claim
95 words
A method for preparing a piezoelectric and pyroelectric film comprising the steps of, biaxially stretching a film made from a resin composition of a polymer of vinylidene fluoride; additionally stretching the thus obtained biaxially stretched film at a temperature of lower than the crystallizing temperature of said resin composition, which additional stretching temperature is lower than the temperature at the biaxially stretching by more than 20° C. and is higher than the secondary transition temperature of said resin composition; and at the same time or after the additional stretching polarizing the thus additionally stretched film
Claim 3
Dependent Claim
18 words
The method according to claim 1, wherein said resin composition comprises a homopolymer or copolymer of vinylidene fluoride.
Claim 4
Dependent Claim
34 words
The method according to claim 1, wherein the temperature at which said additional stretching is carried out is lower than the temperature at which biaxial stretching is carried out by more than 40° C.
Claim 5
Dependent Claim
31 words
The method according to claim 3, wherein said additional stretching is carried out at a temperature more than 60° C. below the temperature at which the biaxial stretching is carried out.
Claim 6
Dependent Claim
38 words
The method according to claim 1, wherein said additional stretching is carried out onto said biaxially stretched film in a state of molecular orientation of a degree higher than -5×10 -3 in the direction of said biaxial stretching.
Claim 7
Dependent Claim
87 words
The method according to claim 1, wherein said biaxially stretched film prior to said additional stretching is in a state of molecular orientation of the degree of 14×10 -3 to 22×10 -3 in the direction of the first monoaxial stretching after the first monoaxial stretching constituting said biaxial stretching and is in a state of molecular orientation of a degree of higher than -5×10 -3 in the direction of second monoaxial stretching after the second monoaxial stretching, said first and second monoaxial stretchings constituting said biaxial stretching.
Claim 8
Dependent Claim
42 words
The method according to claim 6, wherein the direction of said additional stretching is perpendicular to the direction of the second monoaxial stretching constituting said biaxial stretching or oblique to either of the direction of the first stretching or the second stretching.
Claim 9
Dependent Claim
21 words
The method according to claim 1, wherein said additional stretching is a multiple stage-stretching having two or more steps of stretching.
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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) | 1984-09-21 | 1985-03-23 | 1985-09-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-09-21 | 1989-03-23 | 1989-09-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-09-21 | 1993-03-23 | 1993-09-22 | $7700.00 | Window Closed / Lapsed |