US4778867A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ferroelectric copolymers of vinylidene fluoride and trifluoroethylene with increased Curie temperature and their methods of production
Assignee: Individual
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Filing: 1987-07-21
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Granted: 1988-10-18
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Expires: 2007-07-21
Abstract
Abstract A ferroelectric random copolymer consisting essentially of about 65 to 80 mole percent of vinylidene fluoride and 35 to 20 mole percent trifluoroethylene with an increased Curie temperature obtained via a heat-treatment within certain temperature ranges. The heat-treatment can be isothermal or cyclic. The resulting material can be used in nondestructive devices over a wider temperature range than conventional materials.
Inventors
- 👤 Seymour Pries
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:49
CPC Classifications
C; C08; C08J; C08J7/00; C08J7/08; C08F; C08F214/00; C08F214/18; C08F214/22; H; H10; H10N; H10N30/00; H10N30/01; H10N30/04; H10N30/09; H10N30/098; H10N30/80; H10N30/85; H10N30/857; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/16
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
77 words
A heat-treated polymeric material consisting essentially of a random copolymer consisting essentially of 65 to 80 mole percent of vinylidene fluoride and 35 to 20 mole percent of trifluoroethylene, said copolymer having a critical temperature range and a reference Curie Temperature (heating) characterized by a significantly elevated Curie temperature (heating), as a result of heat-treatment for at least 72 hours at a temperature within the critical range and above the reference Curie temperature (heating) of the copolymer.
Claim 2
Dependent Claim
77 words
A heat-treated polymeric material consisting essentially of a random copolymer consisting essentially of 65 to 80 mole percent of vinylidene fluoride and 35 to 20 mole percent of trifluoroethylene, said copolymer having a critical temperature range and a reference Curie Temperature (heating) characterized by a significantly elevated Curie temperature (heating), as a result of heat-treatment for at least 72 hours at a temperature within the critical range and above the reference Curie temperature (heating) of the copolymer.
Claim 3
Dependent Claim
20 words
The invention of claim 1 in which the heat-treatment extends continuously for a period of between 72 and 336 hours.
Claim 4
Dependent Claim
29 words
The invention of claim 2 in which the heat-treatment temperature is about 130 degrees C. and the reference Curie temperature (heating) of the copolymer is about 129 degrees C.
Claim 5
Dependent Claim
25 words
The invention of claim 3 in which the Curie temperature (heating) after heat-treatment is between 137 degrees C. and the melting point of the copolymer.
Claim 6
Dependent Claim
42 words
The invention of claim 1 in which the polymeric material is unpolarized and heat-treatment is isothermal for at least 504 hours at a temperature below the reference Curie temperature (heating) of the copolymer, and within the critical temperature range of the copolymer.
Claim 7
Dependent Claim
43 words
The invention of claim 1 in which the polymeric material is polarized and the heat-treatment is isothermal for at least 504 hours at a temperature below the reference Curie temperature (heating) of the copolymer, and within the critical temperature range of the copolymer.
Claim 8
Dependent Claim
15 words
The invention of claim 5 in which the heat-treatment temperature is about 95 degrees C.
Claim 9
Dependent Claim
15 words
The invention of claim 6 in which the heat-treatment temperature is about 95 degrees C.
Claim 10
Dependent Claim
18 words
The invention of claim 6 in which the polymeric material is polarized by an electrical field before heat-treatment.
Claim 11
Dependent Claim
18 words
The invention of claim 1 in which the polymeric material is polarized by an electrical field after heat-treatment.
Claim 12
Dependent Claim
54 words
The invention of claim 1 in which the heat-treatment is cyclic, having individual cycles of about 12 hours at a temperature which moves alternately to an upper limit above the reference Curie temperature (heating) and within the critical temperature range and to a lower limit below the reference Curie temperature (cooling) of the copolymer.
Claim 13
Dependent Claim
21 words
The invention of claim 11 in which the total heat-treatment cycle lasts for a period of between 72 and 240 hours.
Claim 14
Dependent Claim
51 words
The invention of claim 12 in which the reference Curie temperature (heating) of the copolymer is in the range of 126 to 130 degrees C. and the reference Curie temperature (cooling) is about 75 degrees C., with the heat-treatment temperature upper and lower limits being 137 and 57 degrees C. respectively.
Claim 15
Independent Claim
107 words
A method of significantly elevating by heat-treatment the Curie temperature (heating) of a polymeric material consisting essentially of a random copolymer consisting essentially of 65 to 80 mole percent of vinylidene fluoride and 35 to 20 mole percent trifluoroethylene, said copolymer having a critical temperature range and a reference Curie Temperature (heating) comprising: a. providing the polymeric material in the form of a sheet, film or slug; and b. determining said reference Curie temperature (heating) of said copolymer; and c. isothermally heat-treating the material for at least 72 hours at a temperature within the critical temperature range and above the reference Curie temperature (heating) of the copolymer.
Claim 16
Independent Claim
107 words
A method of significantly elevating by heat-treatment the Curie temperature (heating) of a polymeric material consisting essentially of a random copolymer consisting essentially of 65 to 80 mole percent of vinylidene fluoride and 35 to 20 mole percent trifluoroethylene, said copolymer having a critical temperature range and a reference Curie Temperature (heating) comprising: a. providing the polymeric material in the form of a sheet, film or slug; and b. determining said reference Curie temperature (heating) of said copolymer; and c. isothermally heat-treating the material for at least 72 hours at a temperature within the critical temperature range and above the reference Curie temperature (heating) of the copolymer.
Claim 17
Dependent Claim
21 words
The invention of claim 14 in which the heat-treating period lasts continuously for a period of between 72 and 336 hours.
Claim 18
Dependent Claim
26 words
The invention of claim 15 in which the heat-treatment temperature is about 130 degrees C. and the reference Curie temperature (heating) is about 129 degrees C.
Claim 19
Dependent Claim
19 words
The invention of claim 16 further including the step of polarizing the material in an electrical field after heat-treatment.
Claim 20
Independent Claim
135 words
A method of significantly elevating by heat-treatment the Curie temperature (heating) of a polymeric material consisting essentially of a random copolymer consisting essentially of 65 to 80 mole percent of vinylidene fluoride and 35 to 20 mole percent trifluoroethylene, said copolymer having a critical temperature range, a reference Curie temperature (heating) and a reference Curie temperature (cooling) comprising: a. providing the polymeric material in the form of a sheet, film or slug; and b. determining said reference Curie temperature (heating) and said reference Curie temperature (cooling); and c. cyclically heat-treating the material in individual periods of about 12 hours at a temperature which moves alternately to an upper limit above the reference Curie temperature (heating) and within the critical temperature range and to a lower limit below the reference Curie temperature (cooling) of the copolymer.
Claim 21
Independent Claim
135 words
A method of significantly elevating by heat-treatment the Curie temperature (heating) of a polymeric material consisting essentially of a random copolymer consisting essentially of 65 to 80 mole percent of vinylidene fluoride and 35 to 20 mole percent trifluoroethylene, said copolymer having a critical temperature range, a reference Curie temperature (heating) and a reference Curie temperature (cooling) comprising: a. providing the polymeric material in the form of a sheet, film or slug; and b. determining said reference Curie temperature (heating) and said reference Curie temperature (cooling); and c. cyclically heat-treating the material in individual periods of about 12 hours at a temperature which moves alternately to an upper limit above the reference Curie temperature (heating) and within the critical temperature range and to a lower limit below the reference Curie temperature (cooling) of the copolymer.
Claim 22
Dependent Claim
17 words
The invention of claim 18 in which the total heat-treatment time is between 72 and 240 hours.
Claim 23
Dependent Claim
50 words
The invention of claim 19 in which the reference Curie temperature (heating) of the copolymer is in the range of 126 to 130 degrees C. and the reference Curie temperature (cooling) is about 75 degrees C., with the heat-treating temperature upper and lower limits being 137 and 57 degrees respectively.
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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) | 1991-10-18 | 1992-04-18 | 1992-10-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-18 | 1996-04-18 | 1996-10-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-18 | 2000-04-18 | 2000-10-18 | $7700.00 | Window Closed / Lapsed |