Patent US4481158A successfully refreshed from Google Patents.
US4481158A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Extrusion of films of vinylidene fluoride polymers
Assignee: Solvay SA
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Filing: 1982-11-16
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Granted: 1984-11-06
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Expires: 2002-11-16
Abstract
Abstract The film (11) extruded from a vinylidene fluoride polymer is subjected to a stretching of at least 200% while still in the molten state, and then cooled rapidly to a temperature below 50° C. The equipment comprises, in series, an extruding device (1) (2), a cooling device consisting of a thermostatically controlled liquid bath (6), the level of which is located at a distance of 10 to 300 mm from the extruding device, and a device (8) (9) for stretching the extruded film by at least 200% in its part located between the extruding device and the cooling device. The film obtained is suitable for manufacturing piezoelectric films.
Inventors
- 👤 Pierre Georlette
- 👤 Nestor Maquet
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:18
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/18; B; B29; B29D; B29D7/00; H; H10; H10N; H10N30/00; H10N30/01; H10N30/09; H10N30/098; B29C; B29C48/00; B29C48/001; B29C48/0018; B29C48/03; B29C48/07; B29C48/08; C08J2327/00; C08J2327/02
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
65 words
Process for the extrusion of films of vinylidene fluoride polymers having a predominantly crystalline structure of the beta type, comprising: subjecting an extruded film of molten polymer to a stretching of at least 200% in the direction of extrusion, and cooling the stretched film to a temperature below 50° C. when it has travelled a distance of at most 300 mm after leaving the die.
Claim 2
Dependent Claim
65 words
Process for the extrusion of films of vinylidene fluoride polymers having a predominantly crystalline structure of the beta type, comprising: subjecting an extruded film of molten polymer to a stretching of at least 200% in the direction of extrusion, and cooling the stretched film to a temperature below 50° C. when it has travelled a distance of at most 300 mm after leaving the die.
Claim 3
Dependent Claim
26 words
Process according to claim 1, wherein the film is subjected to a stretching of at least 500%, and is cooled to a temperature below 35° C.
Claim 4
Dependent Claim
26 words
Process according to claim 1, wherein the stretched film is cooled when it has travelled a distance of at most 100 mm after leaving the die.
Claim 5
Dependent Claim
25 words
Process according to claim 1, wherein the stretching is carried out at a film speed, after stretching, which is equal to at least 50 m/minute.
Claim 6
Dependent Claim
25 words
Process for the manufacture of piezoelectric films from films obtained by the process of claim 1, wherein this film is subjected to a polarising treatment.
Claim 7
Dependent Claim
13 words
Process according to claim 1, wherein the polymer is a vinylidene fluoride homopolymer.
Claim 8
Dependent Claim
21 words
Process according to claim 1, wherein the polymer is a vinylidene fluoride copolymer containing at least 85 mol% of vinylidene fluoride.
Claim 9
Dependent Claim
25 words
Process according to claim 2 wherein the stretching is carried out at a film speed, after stretching, which is equal to at least 50 m/minute.
Claim 10
Dependent Claim
25 words
Process for the manufacture of piezoelectric films from films produced by the process of claim 2 wherein this film is subjected to a polarising treatment.
Claim 11
Dependent Claim
14 words
Process according to claim 2 wherein the vinylidene fluoride polymer is vinylidene fluoride homopolymer.
Claim 12
Dependent Claim
23 words
Process according to claim 2 wherein the vinylidene fluoride polymer is a vinylidene fluoride copolymer containing at least 85 mol% of vinylidene fluoride.
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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) | 1987-11-06 | 1988-05-07 | 1988-11-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-06 | 1992-05-07 | 1992-11-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-06 | 1996-05-07 | 1996-11-06 | $7700.00 | Window Closed / Lapsed |