Patent US5366664A successfully refreshed from Google Patents.
US5366664A
Expired / Lapsed
US
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Electromagnetic shielding materials
Assignee: Penn State Research Foundation
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Filing: 1992-05-04
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Granted: 1994-11-22
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Expires: 2012-05-04
Abstract
Abstract The present invention provides for conductive electromagnetic shielding (EMS) compositions which can be formulated to provide effective shielding over a broad range of frequencies, e.g. 30 MHz. to 110 GHz. which is based on a mixture of a polymeric or liquid matrix material and a synergestic combination of conductive powders, fibers and optional flake components. The invention also provides for formulations containing the above composition which are adapted for EMS applications such as pliable caulking, thermoformable shaped articles such as housings and cabinetry, flexible gasket material, shielding curtains, coatings and paints which may be applied to substrates such as glass, plastic or metal, structural composites, conformal coatings for printed circuit boards and like applications.
Inventors
- 👤 Vijay K. Varadan
- 👤 Vasundara V. Varadan
- 👤 Neil R. Williams
- 👤 Joseph W. Cresko
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 11:07
CPC Classifications
H; H05; H05K; H05K9/00; H05K9/0073; H05K9/0081; H05K9/0083; H01; H01B; H01B1/00; H01B1/20; H01B1/22; H01B1/24; H05K1/00; H05K1/02; H05K1/0213; H05K1/0216; H05K1/0218; H05K1/09; H05K1/092; H05K1/095; H05K3/00; H05K3/22; H05K3/28; H05K3/284; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2913; Y10T428/2927; Y10T428/2982; Y10T428/31504; Y10T428/31801
Claims Analysis
Total Claims: 63
Claim 1
Independent Claim
166 words
An electromagnetic shielding composition comprising a mixture of: i) a matrix component selected from the group consisting of silicone oils, curable elastomers, thermoplastic polymers, thermosetting polymers and mixtures thereof; and ii) a synergistic combination of electromagnetic shield enhancing additives comprising a mixture of: a) from about 1 to about 10% by weight of said composition of at least one conductive fiber material; b) from about 5 to about 60% by weight of said composition of a conductive powder material, said powder comprising a metal oxide or metal sulfide core coated with a conductive metal, wherein the weight range of said powder to said fiber is in the range of about 1:10 to about 20:1 respectively; c) from about 0 to about 35% by weight of said composition of a conductive metal flake material; d) from 0 to about 25% by weight of said composition of a liquid organic compound containing at least one cyano group per molecule; said additives being uniformly dispersed in said matrix material.
Claim 2
Dependent Claim
166 words
An electromagnetic shielding composition comprising a mixture of: i) a matrix component selected from the group consisting of silicone oils, curable elastomers, thermoplastic polymers, thermosetting polymers and mixtures thereof; and ii) a synergistic combination of electromagnetic shield enhancing additives comprising a mixture of: a) from about 1 to about 10% by weight of said composition of at least one conductive fiber material; b) from about 5 to about 60% by weight of said composition of a conductive powder material, said powder comprising a metal oxide or metal sulfide core coated with a conductive metal, wherein the weight range of said powder to said fiber is in the range of about 1:10 to about 20:1 respectively; c) from about 0 to about 35% by weight of said composition of a conductive metal flake material; d) from 0 to about 25% by weight of said composition of a liquid organic compound containing at least one cyano group per molecule; said additives being uniformly dispersed in said matrix material.
Claim 3
Dependent Claim
13 words
The composition of claim 1 wherein said matrix material is a silicone oil.
Claim 4
Dependent Claim
15 words
The composition of claim 2 wherein said conductive fiber material is graphite coated with nickel.
Claim 5
Dependent Claim
31 words
The composition of claim 3 wherein said fiber has a length of less than about 0.4 inches and a diameter in the range of from about 3 to about 15 microns.
Claim 6
Dependent Claim
24 words
The composition of claim 2 wherein said conductive powder material is a metal oxide powder coated with a metal selected from antimony or indium.
Claim 7
Dependent Claim
16 words
The composition of claim 5 wherein said conductive powder material is tin oxide coated with antimony.
Claim 8
Dependent Claim
19 words
The composition of claim 2 which contains at least about 1% by weight of said conductive metal flake material.
Claim 9
Dependent Claim
12 words
The composition of claim 7 wherein said metal flake material is nickel.
Claim 10
Dependent Claim
13 words
The composition of claim 1 wherein said matrix material is a curable elastomer.
Claim 11
Dependent Claim
11 words
The composition of claim 9 wherein said elastomer is silicone rubber.
Claim 12
Dependent Claim
19 words
The composition of claim 10 which contains at least about 1% by weight of said conductive metal flake material.
Claim 13
Dependent Claim
32 words
The composition of claim 11 which contains from about 15 to about 35% by weight of said flake material and about 5 to about 30% by weight of said conductive powder material.
Claim 14
Dependent Claim
24 words
The composition of claim 12 wherein said conductive powder material is a metal oxide powder coated with a metal selected from antimony or indium.
Claim 15
Dependent Claim
16 words
The composition of claim 13 wherein said conductive powder material is tin oxide coated with antimony.
Claim 16
Dependent Claim
31 words
The composition of claim 12 wherein said fiber has a length of less than about 0.4 inches and a diameter in the range of from about 5 to about 10 microns.
Claim 17
Dependent Claim
13 words
The composition of claim 14 wherein said conductive flake material is nickel flake.
Claim 18
Dependent Claim
13 words
The composition of claim 1 wherein said matrix material is a thermosetting polymer.
Claim 19
Dependent Claim
19 words
The composition of claim 17 which contains at least about 1% by weight of said conductive metal flake material.
Claim 20
Dependent Claim
32 words
The composition of claim 18 which contains from about 15 to about 35% by weight of said flake material and about 5 to about 30% by weight of said conductive powder material.
Claim 21
Dependent Claim
24 words
The composition of claim 19 wherein said conductive powder material is a metal oxide powder coated with a metal selected from antimony or indium.
Claim 22
Dependent Claim
16 words
The composition of claim 20 wherein said conductive powder material is tin oxide coated with antimony.
Claim 23
Dependent Claim
31 words
The composition of claim 21 wherein said fiber has a length of less than about 0.4 inches and a diameter in the range of from about 5 to about 10 microns.
Claim 24
Dependent Claim
13 words
The composition of claim 22 wherein said conductive flake material is nickel flake.
Claim 25
Dependent Claim
92 words
A pliable caulking composition for electromagnetic shielding applications comprising a uniform admixture of: a) an organopolysiloxane oil; b) about 5 to about 25% by weight of said composition of a liquid organic compound containing at least one cyano group per molecule; c) about 1 to about 10% by weight of said composition of a conductive fiber material; d) about 10 to about 60% by weight of said composition of a conductive powder material, and e) from 0 up to about 35% by weight of said composition of a conductive metal flake material.
Claim 26
Dependent Claim
92 words
A pliable caulking composition for electromagnetic shielding applications comprising a uniform admixture of: a) an organopolysiloxane oil; b) about 5 to about 25% by weight of said composition of a liquid organic compound containing at least one cyano group per molecule; c) about 1 to about 10% by weight of said composition of a conductive fiber material; d) about 10 to about 60% by weight of said composition of a conductive powder material, and e) from 0 up to about 35% by weight of said composition of a conductive metal flake material.
Claim 27
Dependent Claim
19 words
The composition of claim 24 wherein said a liquid organic compound is a polymer containing polymerized acrylonitrile or methacrylonitrile.
Claim 28
Dependent Claim
43 words
The composition of claim 24 wherein said conductive powder material has an average particle size in the range from about 0.1 to about 25 microns and is present in the composition at a level of from about 40 to about 60% by weight.
Claim 29
Dependent Claim
19 words
The composition of claim 26 wherein said conductive powder is a metal oxide core coated with antimony or indium.
Claim 30
Dependent Claim
12 words
The composition of claim 27 wherein said metal oxide is tin oxide.
Claim 31
Dependent Claim
50 words
The composition of claim 24 wherein said conductive fiber has a length of less than about 0.4 inch and a diameter in the range of from about 3 to about 15 microns, and is present in said composition at a level of from about 3 to about 7% by weight.
Claim 32
Dependent Claim
29 words
The composition of claim 29 wherein said conductive fiber is graphite coated with a conductive metal which constitutes from about 3 to about 25% by weight of said fiber.
Claim 33
Dependent Claim
11 words
The composition of claim 30 wherein said conductive metal is nickel.
Claim 34
Dependent Claim
17 words
The composition of claim 24 which contains at least about 1% by weight of said conductive flake.
Claim 35
Dependent Claim
10 words
The composition of claim 32 wherein said flake is nickel.
Claim 36
Dependent Claim
25 words
The composition of claim 24 wherein said organopolysiloxane is present in said composition at a level of from about 20 to about 30% by weight.
Claim 37
Dependent Claim
10 words
The composition of claim 34 wherein said organopolysiloxane is polydimethylsiloxane.
Claim 38
Dependent Claim
17 words
The composition of claim 24 which further contains a plasticizer selected from dialkyl esters of dicarboxylic acids.
Claim 39
Dependent Claim
101 words
A flexible elastomeric sheet material for electromagnetic shielding applications comprising a uniform admixture of: a) a cured elastomeric polymer; b) about 1 to about 10% by weight of said sheet material of a conductive fiber material; c) about 5 to about 60% by weight of said sheet material of a conductive powder material said powder comprising a metal oxide or metal sulfide core coated with a conductive metal; and d) from about 1 to about 35% by weight of said sheet material of a conductive metal flake material, said components b, c and d uniformly dispersed in said cured elastomeric polymer.
Claim 40
Dependent Claim
101 words
A flexible elastomeric sheet material for electromagnetic shielding applications comprising a uniform admixture of: a) a cured elastomeric polymer; b) about 1 to about 10% by weight of said sheet material of a conductive fiber material; c) about 5 to about 60% by weight of said sheet material of a conductive powder material said powder comprising a metal oxide or metal sulfide core coated with a conductive metal; and d) from about 1 to about 35% by weight of said sheet material of a conductive metal flake material, said components b, c and d uniformly dispersed in said cured elastomeric polymer.
Claim 41
Dependent Claim
44 words
The sheet material of claim 37 wherein said conductive powder material has an average particle size in the range from about 0.1 to about 25 microns and is present in the composition at a level of from about 40 to about 60% by weight.
Claim 42
Dependent Claim
21 words
The sheet material composition of claim 38 wherein said conductive powder is a metal oxide core coated with antimony or indium.
Claim 43
Dependent Claim
12 words
The sheet material of claim 39 wherein said metal is tin oxide.
Claim 44
Dependent Claim
51 words
The sheet material of claim 37 wherein said conductive fiber has a length of less than about 0.4 inch and a diameter in the range of from about 3 to about 15 microns, and is present in said composition at a level of from about 3 to about 7% by weight.
Claim 45
Dependent Claim
30 words
The sheet material of claim 41 wherein said conductive fiber is graphite coated with a conductive metal which constitutes from about 3 to about 25% by weight of said fiber.
Claim 46
Dependent Claim
12 words
The sheet material of claim 42 wherein said conductive metal is nickel.
Claim 47
Dependent Claim
20 words
The sheet material of claim 37 which contains from about 15 to about 35% by weight of said conductive flake.
Claim 48
Dependent Claim
11 words
The sheet material of claim 44 wherein said flake is nickel.
Claim 49
Dependent Claim
28 words
The sheet material of claim 37 wherein said elastomeric polymer is present in said sheet material at a level of from about 35 to about 75% by weight.
Claim 50
Dependent Claim
13 words
The sheet material of claim 46 wherein said elastomeric polymer is silicone rubber.
Claim 51
Dependent Claim
149 words
An electromagnetic shielding composition comprising a mixture of: i) a matrix component selected from the group consisting of curable elastomers, thermoplastic polymers, thermosetting polymers and mixtures thereof; and ii) a synergistic combination of electromagnetic shield enhancing additives comprising a mixture of: a) from about 1 to about 10% by weight of said composition of at least one conductive fiber material; b) from about 5 to about 60% by weight of said composition of a conductive powder material, wherein the weight range of said powder to said fiber is in the range of about 1:10 to about 20:1 respectively; c) from 0 to about 35% by weight of said composition of a conductive metal flake material; and d) from 1 to about 25% by weight of said composition of a liquid organic compound containing at least one cyano group per molecule; said additives being uniformly dispersed in said matrix material.
Claim 52
Dependent Claim
149 words
An electromagnetic shielding composition comprising a mixture of: i) a matrix component selected from the group consisting of curable elastomers, thermoplastic polymers, thermosetting polymers and mixtures thereof; and ii) a synergistic combination of electromagnetic shield enhancing additives comprising a mixture of: a) from about 1 to about 10% by weight of said composition of at least one conductive fiber material; b) from about 5 to about 60% by weight of said composition of a conductive powder material, wherein the weight range of said powder to said fiber is in the range of about 1:10 to about 20:1 respectively; c) from 0 to about 35% by weight of said composition of a conductive metal flake material; and d) from 1 to about 25% by weight of said composition of a liquid organic compound containing at least one cyano group per molecule; said additives being uniformly dispersed in said matrix material.
Claim 53
Dependent Claim
13 words
The composition of claim 48 wherein said matrix material is a polysiloxane elastomer.
Claim 54
Dependent Claim
23 words
The composition of claim 48 wherein said organic compound is liquid polyacrylonitrile, a liquid copolymer of butadiene and acrylonitrile or a mixture thereof.
Claim 55
Dependent Claim
15 words
The composition of claim 48 wherein said conductive fiber material is graphite coated with nickel.
Claim 56
Dependent Claim
31 words
The composition of claim 51 wherein said fiber has a length of less than about 0.4 inches and a diameter in the range of from about 3 to about 15 microns.
Claim 57
Dependent Claim
24 words
The composition of claim 48 wherein said conductive powder material is a metal oxide powder coated with a metal selected from antimony or indium.
Claim 58
Dependent Claim
16 words
The composition of claim 53 wherein said conductive powder material is tin oxide coated with antimony.
Claim 59
Dependent Claim
19 words
The composition of claim 48 which contains at least about 1% by weight of said conductive metal flake material.
Claim 60
Dependent Claim
12 words
The composition of claim 55 wherein said metal flake material is nickel.
Claim 61
Dependent Claim
32 words
The composition of claim 55 which contains from about 15 to about 35% by weight of said flake material and about 5 to about 30% by weight of said conductive powder material.
Claim 62
Dependent Claim
24 words
The composition of claim 57 wherein said conductive powder material is a metal oxide powder coated with a metal selected from antimony or indium.
Claim 63
Dependent Claim
16 words
The composition of claim 58 wherein said conductive powder material is tin oxide coated with antimony.
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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) | 1997-11-21 | 1998-05-23 | 1998-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-11-21 | 2002-05-23 | 2002-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-11-21 | 2006-05-23 | 2006-11-22 | $7700.00 | Window Closed / Lapsed |