Patent US4291245A successfully refreshed from Google Patents.
US4291245A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrets
Assignee: Union Carbide Chemicals and Plastics Technology LLC
•
Filing: 1979-09-04
•
Granted: 1981-09-22
•
Expires: 1999-09-04
Abstract
Abstract A process for preparing polymer electrets comprising the following steps: (a) providing a parylene film having one side affixed to a metal layer and grounding said metal layer; (b) charging the free side of the film with a direct current corona, the charge being of sufficient magnitude to convert the film to an electret; (c) providing p-xylylene monomer vapor in sufficient amount to coat the charged film; and (d) introducing the vapor from step (c) and the electret into a deposition zone, said zone being under vacuum and at a temperature at which the vapor will condense, whereby the electret is conformally coated with parylene.
Inventors
- 👤 Thomas E. Nowlin
- 👤 Curt R. Raschke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:03
CPC Classifications
H; H01; H01G; H01G7/00; H01G7/02; H01G7/021; H01G7/023; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/913; Y10S428/922; Y10S428/9265; Y10S428/929; Y10S428/9335; Y10S428/934; Y10S428/938; Y10S55/00; Y10S55/39; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31678; Y10T428/31692
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
106 words
A process for preparing polymer electrets comprising the following steps: (a) providing a parylene film having one side affixed to a metal layer and grounding said metal layer; (b) charging the free side of the film with a direct current corona, the charge being of sufficient magnitude to convert the film to an electret; (c) providing a p-xylylene monomer vapor in sufficient amount to coat the charged film; and (d) introducing the vapor from step (c) and the electret into a deposition zone, said zone being under vacuum and at a temperature at which the vapor will condense, whereby the electret is conformally coated with parylene.
Claim 2
Dependent Claim
106 words
A process for preparing polymer electrets comprising the following steps: (a) providing a parylene film having one side affixed to a metal layer and grounding said metal layer; (b) charging the free side of the film with a direct current corona, the charge being of sufficient magnitude to convert the film to an electret; (c) providing a p-xylylene monomer vapor in sufficient amount to coat the charged film; and (d) introducing the vapor from step (c) and the electret into a deposition zone, said zone being under vacuum and at a temperature at which the vapor will condense, whereby the electret is conformally coated with parylene.
Claim 3
Dependent Claim
20 words
The process defined in claim 1 wherein the parylene used in step (a) has chloro, dichloro, cyano, or dicyano substituents.
Claim 4
Dependent Claim
25 words
The process defined in claim 1 wherein fluorine atoms are substituted for the hydrogen atoms of the methylene groups in the parylene film or monomer.
Claim 5
Dependent Claim
37 words
An electret comprising, in combination, (i) a metal layer coated with a film of parylene, said parylene film having a surface charge; (ii) an external electric field; and (iii) a conformal parylene overcoat on the charged surface.
Claim 6
Dependent Claim
37 words
An electret comprising, in combination, (i) a metal layer coated with a film of parylene, said parylene film having a surface charge; (ii) an external electric field; and (iii) a conformal parylene overcoat on the charged surface.
Claim 7
Dependent Claim
16 words
The electret defined in claim 4 wherein the parylene has chloro, dichloro, cyano, or dicyano substiuents.
Claim 8
Dependent Claim
25 words
The electret defined in claim 4 wherein fluorine atoms are substituted for the hydrogen atoms of the methylene groups in the parylene film or overcoat.
References Cited (Backward Citations)
US3246627A
Cited
US3301707A
Cited
US3421930A
Cited
US3600216A
Cited
US3663265A
Cited
US4186164A
Cited
US3956525A
Cited
US4047998A
Cited
US4018945A
Cited
US4054680A
Cited
US4086499A
Cited
US4123308A
Cited
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 |