US4244894A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process and apparatus for the manufacture of films by electrostatic application
Assignee: Cellophane SA France
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Filing: 1979-01-22
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Granted: 1981-01-13
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Expires: 1999-01-22
Abstract
Abstract Process and apparatus for electrostatically pinning a dielectric film to a moving surface which is electrically conducting and connected to a grounded fixed potential comprising a corona wire fed with a direct current and a semi-cylindrical metal counter-electrode connected to a potential which is approximately equal to the potential of the moving surface. When extruding a molten mass of polymer onto a cooling surface, a substantial increase in the speed of application is observed. The best results are obtained when the radius of the counter-electrode is approximately equal to the distance between the corona wire and the moving surface.
Inventors
- 👤 Michel Segransan
- 👤 Jean-Claude Joly
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:38
CPC Classifications
H; H01; H01T; H01T19/00; B; B29; B29C; B29C48/00; B29C48/03; B29C48/07; B29C48/08; B29C48/25; B29C48/88; B29C48/911; B29C48/9135; B29C48/914; B29C48/915; B29C48/9165
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
155 words
A process for electrostatically pinning a dielectric film to an electrically conducting moving surface which is connected to a fixed potential, the film being applied to the moving surface with the aid of a corona electrode consisting of a metal wire fed with direct current which is arranged parallel to the said surface, and a second electrode being arranged near the corona electrode and parallel to the corona electrode, said process comprising the steps of: providing as the second electrode an uninsulated counter-electrode having a concave face and made of an electrically conducting material, said corona electrode being located between the uninsulated counter electrode and said moving surface; connecting the counter-electrode to a fixed potential which is approximately equal to the potential of the moving surface; and locating the concave face of the counter-electrode in front of the corona electrode so that an electric current can be established between the corona electrode and the counter-electrode.
Claim 2
Dependent Claim
155 words
A process for electrostatically pinning a dielectric film to an electrically conducting moving surface which is connected to a fixed potential, the film being applied to the moving surface with the aid of a corona electrode consisting of a metal wire fed with direct current which is arranged parallel to the said surface, and a second electrode being arranged near the corona electrode and parallel to the corona electrode, said process comprising the steps of: providing as the second electrode an uninsulated counter-electrode having a concave face and made of an electrically conducting material, said corona electrode being located between the uninsulated counter electrode and said moving surface; connecting the counter-electrode to a fixed potential which is approximately equal to the potential of the moving surface; and locating the concave face of the counter-electrode in front of the corona electrode so that an electric current can be established between the corona electrode and the counter-electrode.
Claim 3
Dependent Claim
14 words
The process according to claim 1 characterized in that the moving surface is grounded.
Claim 4
Dependent Claim
70 words
The process according to claim 1 characterized in that the radius of the counter-electrode is approximately equal to the distance between the corona electrode and the moving surface, the corona electrode being arranged along the axis of the counter-electrode, and wherein the counter-electrode is located at a distance from the moving surface which is greater than or equal to half the distance separating the corona electrode from the moving surface.
Claim 5
Dependent Claim
31 words
The process according to claim 1 characterized in that the counter-electrode is arranged symmetrically relative to the plane which is normal to the cooling surface and passes through the corona wire.
Claim 6
Dependent Claim
57 words
The process according to claims 1, 2, 3 or 4 characterized in that the counter-electrode is semi-cylindrical and faces the moving surface, in that the moving surface is a cooling surface; and in that the film is a thermoplastic film which is extruded in the form of a molten web onto the cooling surface using a die.
Claim 7
Dependent Claim
46 words
The process according to claim 5 characterized in that the counter-electrode is heated at a temperature which is greater than the condensation temperature of the products generated by the extrusion of the plastic, so as to maintain the electric current between the electrode and the counter-electrode.
Claim 8
Dependent Claim
29 words
The process according to claim 6 in which a molten web of polyethylene terephthalate is extruded, characterized in that the counter-electrode is heated to a temperature above 315° C.
Claim 9
Dependent Claim
143 words
In a device for the application of a dielectric film to an electrically conducting moving surface which is connected to a fixed potential, the film being applied to the moving surface with the aid of a corona electrode consisting of a metal wire which is arranged parallel to the surface and fed with direct current and a second electrode being arranged near the corona electrode and parallel to the latter, the improvement comprising: the second electrode comprising a counter-electrode which is made of an electrically conducting material and shaped to partially enclose the corona electrode, said counter-electrode being connected to a fixed potential which is approximately equal to the potential of the moving surface, the corona electrode being arranged along the axis of the counter-electrode, said counter-electrode being uninsulated so that an electric current is established between the corona electrode and the counter-electrode.
Claim 10
Dependent Claim
143 words
In a device for the application of a dielectric film to an electrically conducting moving surface which is connected to a fixed potential, the film being applied to the moving surface with the aid of a corona electrode consisting of a metal wire which is arranged parallel to the surface and fed with direct current and a second electrode being arranged near the corona electrode and parallel to the latter, the improvement comprising: the second electrode comprising a counter-electrode which is made of an electrically conducting material and shaped to partially enclose the corona electrode, said counter-electrode being connected to a fixed potential which is approximately equal to the potential of the moving surface, the corona electrode being arranged along the axis of the counter-electrode, said counter-electrode being uninsulated so that an electric current is established between the corona electrode and the counter-electrode.
Claim 11
Dependent Claim
13 words
The device according to claim 8 further comprising means for heating the counter-electrode.
Claim 12
Dependent Claim
20 words
The device according to claim 8 wherein the counter-electrode has an open face which is orientated toward the moving surface.
Claim 13
Dependent Claim
11 words
The device according to claim 8 wherein said counter-electrode is semi-cylindrical.
Claim 14
Dependent Claim
27 words
The device according to claim 11 wherein the radius of the said counter-electrode is approximately equal to the distance between the corona electrode and the moving surface.
Claim 15
Independent Claim
23 words
The device according to claims 8 or 9 wherein said counter-electrode has a concave face which is in front of the corona electrode.
Claim 16
Dependent Claim
36 words
The device according to claim 8 wherein the counter-electrode is located at a distance from the moving surface which is greater than or equal to half the distance separating the corona electrode and the moving surface.
Claim 17
Independent Claim
20 words
The device according to claims 11 or 12 wherein the radius of the counter-electrode is between 3 and 15 mm.
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) | 1984-01-13 | 1984-07-14 | 1985-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-13 | 1988-07-14 | 1989-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-13 | 1992-07-14 | 1993-01-13 | $7700.00 | Window Closed / Lapsed |