US4308312A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dielectric films with increased voltage endurance
Assignee: Von Roll Isola USA Inc
•
Filing: 1980-07-16
•
Granted: 1981-12-29
•
Expires: 2000-07-16
Abstract
Abstract A dielectric film with improved voltage endurance is disclosed. The dielectric film is provided with an aluminum oxide powder dust coating which increases the life of the film by improving the voltage endurance. A film comprising mica reinforced with polyester and/or glass is especially useful in the manufacture of insulating tapes and cloths found in electrical devices. Best voltage endurance is provided by fumed aluminum oxide particles which are in the colloidal size range and which are more than 99.5% pure.
Inventors
- 👤 Raymond C. Urban
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:50
CPC Classifications
H; H01; H01B; H01B3/00; H01B3/02; H01B3/04; H02; H02K; H02K3/00; H02K3/32; H02K3/34; Y; Y10; Y10T; Y10T428/00; Y10T428/25; Y10T428/251; Y10T428/256; Y10T428/257; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/29; Y10T428/2911; Y10T428/31504; Y10T428/31678; Y10T428/31681; Y10T428/31786; Y10T442/00; Y10T442/20; Y10T442/2475; Y10T442/2926; Y10T442/2992
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
35 words
An improved dielectric insulating film which carries on at least one side an aluminum oxide dust coating and comprises a resin-impregnated mica mat reinforced with glass cloth or non-woven glass yarn and a polyester film.
Claim 2
Dependent Claim
35 words
An improved dielectric insulating film which carries on at least one side an aluminum oxide dust coating and comprises a resin-impregnated mica mat reinforced with glass cloth or non-woven glass yarn and a polyester film.
Claim 3
Dependent Claim
17 words
An improved film as recited in claim 1 wherein said polyester film is thinner than said mat.
Claim 4
Dependent Claim
21 words
An improved film as recited in claim 1 wherein said film comprises a mica mat impregnated with a cured solventless polyester.
Claim 5
Dependent Claim
19 words
An improved film as recited in claim 1 comprising a layer of an adhesive which contains aluminum oxide powder.
Claim 6
Dependent Claim
17 words
An improved film as recited in claim 1 having a thickness of at least about 0.001 inch.
Claim 7
Dependent Claim
18 words
An improved film as recited in claim 1 wherein the aluminum oxide dust is at least 99.5% pure.
Claim 8
Dependent Claim
25 words
An improved film as recited in claim 1 wherein the aluminum oxide dust is composed of fumed aluminum oxide particles in the colloidal size range.
Claim 9
Dependent Claim
33 words
An improved film as recited in claim 1 wherein the aluminum oxide dust is composed of particles having a specific surface area in the range of 50 to 150 square meters per gram.
Claim 10
Dependent Claim
22 words
An improved film as recited in claim 1 wherein the coating of aluminum oxide dust particles is at least 10 particles thick.
Claim 11
Dependent Claim
14 words
An improved film as recited in claim 1 wherein the aluminum oxide is acidic.
References Cited (Backward Citations)
US2156083A
Cited
US2763315A
Cited
US2748019A
Cited
US3066180A
Cited
US3556925A
Cited
US3470045A
Cited
US3592711A
Cited
US3470013A
Cited
US3514326A
Cited
US3655263A
Cited
US3746566A
Cited
US3801427A
Cited
US3780206A
Cited
US3935375A
Cited
US4146031A
Cited
US4157414A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-12-28 | 1985-06-29 | 1985-12-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-12-28 | 1989-06-29 | 1989-12-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-12-28 | 1993-06-29 | 1993-12-29 | $7700.00 | Window Closed / Lapsed |