EP0238291A1
Expired / Lapsed
EP
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Electromagnetic wave absorbers
Assignee: Nippon Carbon Co Ltd
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Filing: 1987-03-17
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Granted: —
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Expires: 2007-03-17
Abstract
Abstract An electromagnetic wave absorber comprising a surface layer (2) made of a composite of fibers having an electrical specific resistance of more than 10⁴ Ωcm and a resin, and a wave absorbing layer (3) made of a composite containing silicon carbide fibers having an electrical specific resistance of from 10⁻² to 10⁴ Ωcm. The composite used in the surface layer may be prepared, for example, by impregnating the resin in between the fibers after they have been treated to be a woven cloth, mat or felt or unidirectionally arranged fibers. If a wave absorbing layer is to be made of a composite containing the silicon carbide fibers and a resin, then the composite may be prepared in the same way as the above.
Inventors
- 👤 Toshikatsu Ishikawa
- 👤 Haruo Teranishi
- 👤 Hiroshi Ichikawa
- 👤 Kenji Ushikoshi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 20:56
CPC Classifications
H; H01; H01Q; H01Q17/00; H01Q17/005; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24942; Y10T428/29; Y10T428/2913; Y10T428/2918; Y10T442/00; Y10T442/30; Y10T442/3382; Y10T442/3415; Y10T442/3472; Y10T442/3528
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
52 words
An electromagnetic wave absorber comprising a surface layer made of a composite of fibers having an electrical specific resistance of more than 10⁴ Ωcm and a resin, and a wave absorbing layer made of at least one composite containing silicon carbide fibers having an electrical specific resistance of 10⁻² to 10⁴ Ωcm.
Claim 2
Dependent Claim
52 words
An electromagnetic wave absorber comprising a surface layer made of a composite of fibers having an electrical specific resistance of more than 10⁴ Ωcm and a resin, and a wave absorbing layer made of at least one composite containing silicon carbide fibers having an electrical specific resistance of 10⁻² to 10⁴ Ωcm.
Claim 3
Dependent Claim
26 words
An electromagnetic wave absorber according to claim 1, wherein the silicon carbide fibers used in the wave absorbing layer are prepared from an organic silicon compound.
Claim 4
Dependent Claim
20 words
An electromagnetic wave absorber according to claim 1, wherein the fibers used in the surface layer are silicon carbide fibers.
Claim 5
Dependent Claim
17 words
An electromagnetic wave absorber according to claim 1, wherein the wave absorbing layer is a multi-laminated layer.
Claim 6
Dependent Claim
56 words
An electromagnetic wave absorber according to claim 4, wherein the multi-laminated layer is prepared by laminating together the composites containing silicon carbide fibers having different electrical specific resistances in such a manner that the different electrical specific resistances of the laminated layers are decreasingly gradient in the direction from the outermost layer towards the innermost layer.
Claim 7
Dependent Claim
69 words
An electromagnetic wave absorber according to claim 1, wherein the composite used in the wave absorbing layer is in the form of a woven cloth or mat made of silicon carbide fibers and carbon fibers in a mixing ratio of 20:1 to 60:40 between the silicon carbide fibers and the carbon fibers, and the electrical specific resistance of the composite is in the range of 10⁻² to 10⁴ Ωcm.
Claim 8
Dependent Claim
24 words
An electromagnetic wave absorber according to claim 1, wherein the composite used in the wave absorbing layer further comprises a resin containing inorganic material.
Claim 9
Dependent Claim
19 words
An electromagnetic wave absorber according to claim 7, wherein the inorganic material is carbon, titanium oxide or barium titanate.
Claim 10
Dependent Claim
27 words
An electromagnetic wave absorber according to claim 7, wherein the resin contains the inorganic material in an amount of 0.1 to 50.0% by weight of the resin.
Claim 11
Dependent Claim
18 words
An electromagnetic wave absorber according to claim 1, wherein the resins contained in the composites are thermosetting resins.
Claim 12
Dependent Claim
20 words
An electromagnetic wave absorber according to claim 10, wherein the thermosetting resins are epoxy type resins or phenol type resins.
Claim 13
Dependent Claim
18 words
An electromagnetic wave absorber according to claim 1, wherein the resins contained in the composites are thermoplastic resins.
Claim 14
Dependent Claim
23 words
An electromagnetic wave absorber according to claim 12, wherein the thermoplastic resin is polyester, polyphenylene sulfide, nylon, polyether sulfone or polyether ehter ketone.
Claim 15
Dependent Claim
40 words
An electromagnetic wave absorber according to claim 1, wherein the wave absorbing layer is further laminated, at the far side with respect to the surface layer, with a composite made of carbon fibers, a resin and a thin metal plate.
Claim 16
Dependent Claim
31 words
An electromagnetic wave absorber according to claim 1, wherein the wave absorbing layer is further laminated, at the far side with respect to the surface layer, with a thin metal plate.
References Cited (Backward Citations)
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