US4412029A
Expired / Lapsed
US
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Elastomeric composition for providing electrical stress control
Assignee: 3M Co
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Filing: 1981-03-02
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Granted: 1983-10-25
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Expires: 2001-03-02
Abstract
Abstract A permanently elastic dielectric composition comprising a resilient dielectric base material, an electrically polarizable component having low electrical conductivity to increase the relative dielectric constant of the composition, and a component displaying metal conductivity for maintenance of the relative dielectric constant at high power frequencies.
Inventors
- 👤 Dieter Kehr
- 👤 Manfred Viebranz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 15:27
CPC Classifications
H; H02; H02G; H02G15/00; H02G15/08; H02G15/10; H02G15/103; C; C08; C08K; C08K3/00; H01; H01B; H01B3/00; H01B3/002; H01B3/004; H01B3/18; H01B3/30; H01B3/44; H01B3/441; H01B3/46; H02G15/02; H02G15/06; H02G15/064
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
144 words
A permanently elastic dielectric composition for influencing electrical fields in power current and high voltage systems, comprising a permanently resilient dielectric base material, a finely divided effect material to increase the relative dielectric constant, comprising strongly structurized dust-fine particles of an electrically polarizable material of low electrical conductivity, in sufficient concentration, but less than about 3 O parts per hundred parts of said base material, to provide, within the range composition in combination: (a) An electric volume resistivity of at least about 10 6 ohn cm at room temperature, (b) A relative dielectric constant between about 30 to about 300, (c) A dielectric loss factor of less than about 1.5, and a content of a supplemental effect material comprising finely divided particles possessing metal conductivity, in sufficient concentration to maintain the relative dielectric constant at not less than about 20 at high power frequencies.
Claim 2
Dependent Claim
144 words
A permanently elastic dielectric composition for influencing electrical fields in power current and high voltage systems, comprising a permanently resilient dielectric base material, a finely divided effect material to increase the relative dielectric constant, comprising strongly structurized dust-fine particles of an electrically polarizable material of low electrical conductivity, in sufficient concentration, but less than about 3 O parts per hundred parts of said base material, to provide, within the range composition in combination: (a) An electric volume resistivity of at least about 10 6 ohn cm at room temperature, (b) A relative dielectric constant between about 30 to about 300, (c) A dielectric loss factor of less than about 1.5, and a content of a supplemental effect material comprising finely divided particles possessing metal conductivity, in sufficient concentration to maintain the relative dielectric constant at not less than about 20 at high power frequencies.
Claim 3
Dependent Claim
12 words
The composition of claim 1, wherein said effect material is carbon black.
Claim 4
Dependent Claim
27 words
The composition of claim 1, wherein said electric volume resistivity has a temperature coefficient in the temperature range of about 0° to 100° C. of about zero.
Claim 5
Dependent Claim
19 words
The composition of claim 1, wherein said relative dielectric constant is between 50 and 150 at low power frequencies.
Claim 6
Dependent Claim
21 words
The composition of claim 1 wherein said dielectric loss factor is about 1 at low and high frequencies at room temperature.
Claim 7
Dependent Claim
15 words
The composition of claim 1, wherein said supplemental effect material consists of finely divided microspheres.
Claim 8
Dependent Claim
12 words
The composition of claim 6, wherein said microspheres are only superficially conductive.
Claim 9
Dependent Claim
17 words
The composition of claim 6, wherein said microspheres have a diameter of at least about 2 μm.
Claim 10
Dependent Claim
15 words
The composition of claim 1, wherein said supplemental effect metal consists of finely divided platelets.
Claim 11
Dependent Claim
12 words
The composition of claim 1, wherein said supplemental effect material is aluminum.
Claim 12
Dependent Claim
30 words
The composition of claim 10, wherein said aluminum is present at a concentration of about 3 to 15 parts by weight per 100 parts by weight of said base material.
Claim 13
Dependent Claim
22 words
The composition of claim 1, additionally comprising an insulating material different from said base material in finely divided form as platelet-shaped particles.
Claim 14
Dependent Claim
19 words
The composition of claim 12, wherein said insulating material has a dielectric strength not less than said base material.
Claim 15
Dependent Claim
11 words
The composition of claim 12, wherein said insulating material is mica.
Claim 16
Dependent Claim
30 words
The composition of claim 14, wherein said mica is present at a concentration of about 5 to 30 parts by weight per 100 parts by weight of said base material.
Claim 17
Dependent Claim
21 words
The composition of claim 1, in the form of a shaped body capable of functioning as a refractive stress control element.
Claim 18
Dependent Claim
19 words
The composition of claim 16, wherein said body is a sleeve capable of resiliently sliding on a cable termination.
Claim 19
Dependent Claim
20 words
The composition of claim 1, wherein said base material is selected from the group consisting of silicone rubber and EPDM.
References Cited (Backward Citations)
US3349164A
Cited
US3655565A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-10-24 | 1987-04-25 | 1987-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-24 | 1991-04-25 | 1991-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-24 | 1995-04-25 | 1995-10-25 | $7700.00 | Window Closed / Lapsed |