US4390674A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Uniaxially drawn vinylidene fluoride polymers
Assignee: University of Leeds Industrial Services Ltd
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Filing: 1980-12-01
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Granted: 1983-06-28
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Expires: 2000-12-01
Abstract
Abstract An elongated material comprising a vinylidene fluoride polymer and having a Young's modulus from 3 to 15 GPa and which, when poled, has a pyroelectric constant from 4 to 15 nC cm -2 K -1 , or a hydrostatic piezoelectric constant greater than 10 pCN -1 .
Inventors
- 👤 Ian M. Ward
- 👤 John C. McGrath
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:32
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/18; H; H10; H10N; H10N15/00; H10N15/10; H10N15/15; H10N30/00; H10N30/01; H10N30/09; H10N30/098; H10N30/80; H10N30/85; H10N30/857; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/16; Y; Y10; Y10S; Y10S428/00; Y10S428/91; Y10T; Y10T428/00; Y10T428/26; Y10T428/269; Y10T428/31504; Y10T428/3154
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
72 words
A process for the preparation of a piezoelectric, pyroelectric polyvinylidene fluoride polymer material having a Young's modulus of from 3 to 15 GPa comprising uniaxially drawing in one direction only a sheet of polyvinylidene fluoride at a temperature of from 110° C. to 170° C. to a draw ratio of at least 6 to 1 and poling the drawn sheet by applying an electric field across its thickness to effect its polarization.
Claim 2
Dependent Claim
72 words
A process for the preparation of a piezoelectric, pyroelectric polyvinylidene fluoride polymer material having a Young's modulus of from 3 to 15 GPa comprising uniaxially drawing in one direction only a sheet of polyvinylidene fluoride at a temperature of from 110° C. to 170° C. to a draw ratio of at least 6 to 1 and poling the drawn sheet by applying an electric field across its thickness to effect its polarization.
Claim 3
Dependent Claim
20 words
The process of claim 1, wherein the drawing is done at a temperature of from 130° C. to 150° C.
Claim 4
Dependent Claim
18 words
The process of claim 1, wherein the draw ratio is from 6 to 1 to 10 to 1.
Claim 5
Dependent Claim
16 words
The process of claim 1, wherein the electric field applied is from 100 to 500 volt/micron.
Claim 6
Dependent Claim
33 words
The process of claim 1, wherein the uniaxial drawing is done in one direction only but in at least two stages to achieve a total draw ratio of at least 6 to 1.
Claim 7
Dependent Claim
91 words
A polyvinylidene fluoride polymer sheet that is uniaxially stretched in one direction and has a Young's modulus of 3 to 15 GPa, a pyroelectric constant of from 4 to 15 nC cm-2K-1 and a hydrostatic piezoelectric constant greater than 10 pCN-1 produced by uniaxially drawing in one direction only a sheet of polyvinylidene fluoride at a temperature of from 110° C. to 170° C. to a draw ratio of at least 6 to 1 and poling the drawn sheet by applying an electric field across its thickness to effect its polarization.
Claim 8
Dependent Claim
91 words
A polyvinylidene fluoride polymer sheet that is uniaxially stretched in one direction and has a Young's modulus of 3 to 15 GPa, a pyroelectric constant of from 4 to 15 nC cm-2K-1 and a hydrostatic piezoelectric constant greater than 10 pCN-1 produced by uniaxially drawing in one direction only a sheet of polyvinylidene fluoride at a temperature of from 110° C. to 170° C. to a draw ratio of at least 6 to 1 and poling the drawn sheet by applying an electric field across its thickness to effect its polarization.
Claim 9
Dependent Claim
16 words
The sheet of claim 6 having a pyroelectric constant of from 4 to 10 nC cm-2K-1.
Claim 10
Dependent Claim
14 words
The sheet of claim 6 having a hydrostatic piezoelectric constant greater than 16 pCN-1.
Claim 11
Dependent Claim
16 words
The sheet of claim 6, which has a Young's modulus of from 3 to 10 GPa.
Claim 12
Dependent Claim
20 words
The sheet of claim 6, wherein at least 70% by volume of the total crystalline material is Form I material.
References Cited (Backward Citations)
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US3878274A
Cited
US3798473A
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US4298719A
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US4241128A
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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) | 1986-06-27 | 1986-12-27 | 1987-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-06-27 | 1990-12-27 | 1991-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-06-27 | 1994-12-27 | 1995-06-28 | $7700.00 | Window Closed / Lapsed |