CA1267942A - Electrically conductive composite material - Google Patents
Electrically conductive composite materialInfo
- Publication number
- CA1267942A CA1267942A CA000523507A CA523507A CA1267942A CA 1267942 A CA1267942 A CA 1267942A CA 000523507 A CA000523507 A CA 000523507A CA 523507 A CA523507 A CA 523507A CA 1267942 A CA1267942 A CA 1267942A
- Authority
- CA
- Canada
- Prior art keywords
- composite material
- electrically conductive
- cellular
- free space
- electrically
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
- H02G3/00—Installations of electric cables or lines or protective tubing therefor in or on buildings, equivalent structures or vehicles
- H02G3/22—Installations of cables or lines through walls, floors or ceilings, e.g. into buildings
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
- H01B1/20—Conductive material dispersed in non-conductive organic material
- H01B1/22—Conductive material dispersed in non-conductive organic material the conductive material comprising metals or alloys
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S428/00—Stock material or miscellaneous articles
- Y10S428/913—Material designed to be responsive to temperature, light, moisture
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
- Y10T428/24996—With internal element bridging layers, nonplanar interface between layers, or intermediate layer of commingled adjacent foam layers
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
- Y10T428/249962—Void-containing component has a continuous matrix of fibers only [e.g., porous paper, etc.]
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
- Y10T428/249962—Void-containing component has a continuous matrix of fibers only [e.g., porous paper, etc.]
- Y10T428/249964—Fibers of defined composition
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
- Y10T428/249967—Inorganic matrix in void-containing component
- Y10T428/24997—Of metal-containing material
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249994—Composite having a component wherein a constituent is liquid or is contained within preformed walls [e.g., impregnant-filled, previously void containing component, etc.]
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249994—Composite having a component wherein a constituent is liquid or is contained within preformed walls [e.g., impregnant-filled, previously void containing component, etc.]
- Y10T428/249998—Indefinite plurality of similar impregnated thin sheets [e.g., "decorative laminate" type, etc.]
Abstract
ABSTRACT
ELECTRICALLY CONDUCTIVE COMPOSITE MATERIAL
Electrically conductive composite material compri-ses:
(a) an open-celled cellular structure of polymeric material, preferably an open-celled foam, having electrically conductive material on at least its interior surface defining the cells, e.g. depo-sited metal; and (b) substantially solid, preferably non-conductive, material overlying and/or filling the cellular structure.
The solid material (b) is preferably polymeric and may be formed in situ by polymerisation of a monomer oligomer or may be introduced e.g. in molten form.
The material is useful for electromagnetic shielding, e.g. for cable feedthrough glands or dimen-sionally recoverable articles.
ELECTRICALLY CONDUCTIVE COMPOSITE MATERIAL
Electrically conductive composite material compri-ses:
(a) an open-celled cellular structure of polymeric material, preferably an open-celled foam, having electrically conductive material on at least its interior surface defining the cells, e.g. depo-sited metal; and (b) substantially solid, preferably non-conductive, material overlying and/or filling the cellular structure.
The solid material (b) is preferably polymeric and may be formed in situ by polymerisation of a monomer oligomer or may be introduced e.g. in molten form.
The material is useful for electromagnetic shielding, e.g. for cable feedthrough glands or dimen-sionally recoverable articles.
Description
~ ~2~9~L~
RAYCHEM LIMITED ~ 288 .
E:LECTP~ICALLY CONDUCTIVE COMPOSITE MATERIAL
. ~ , , . .
! This invention relates-to an electrically conduc- -tive composite material-, and to articles using electri-cally conductive~composite material.
, Rnown electrically conductive composites include a nfelt~ sheet ,of sintered metal fibres filled with , silicone elastomer, which is used in ,flat gaskets to providé environmental sealing and EMI shielcling con-tinuit~ ~tweenl mating surfaces in electr,ical equip-ment. ;Ela~tome~ filled metal screens, woven ~r,knitted metal filled with~ elastomer, and sheets of elastomers filled with carbon or metal particles or f ibres are also known for such gaskets.
: . -The present invention provides a new composite having an advantageous combination of high electrical conductivity and desirable retention of the filling polymer characteristics.
The invention accordingly provides an electrically conductive composite material comprising (a) an open-celled cellular structure of polymeric material having electrically conductive material on at least its interior surface defining the cellular free ~pace, and ~ ~Z~79~2
RAYCHEM LIMITED ~ 288 .
E:LECTP~ICALLY CONDUCTIVE COMPOSITE MATERIAL
. ~ , , . .
! This invention relates-to an electrically conduc- -tive composite material-, and to articles using electri-cally conductive~composite material.
, Rnown electrically conductive composites include a nfelt~ sheet ,of sintered metal fibres filled with , silicone elastomer, which is used in ,flat gaskets to providé environmental sealing and EMI shielcling con-tinuit~ ~tweenl mating surfaces in electr,ical equip-ment. ;Ela~tome~ filled metal screens, woven ~r,knitted metal filled with~ elastomer, and sheets of elastomers filled with carbon or metal particles or f ibres are also known for such gaskets.
: . -The present invention provides a new composite having an advantageous combination of high electrical conductivity and desirable retention of the filling polymer characteristics.
The invention accordingly provides an electrically conductive composite material comprising (a) an open-celled cellular structure of polymeric material having electrically conductive material on at least its interior surface defining the cellular free ~pace, and ~ ~Z~79~2
- 2\ - RR288 (b) substanti~lly ~olid filling material substantially filling at least part of the cellular free space.
~ he composite material according to this invention is able to provide a substantially continuous three-- dimensional network of the electrically conductive material giving good cvnductivity while minimising the amount of metal present in the composite, since a thin layer of the conductive material on t~e cell-defining interior surface of the polymer structure will suffice.
Because the conductive material is thus minimised, the composite is enabled to retain much of the charact~r of i thP filling material. In preferred forms, where the filling is flexible e.g. elastomeric, the cellular structure and the conductive material, (usual~y metal), can be sufficiently flexible for the composite to be 6argely e~astomeric in character. The filling material - filiing ~he cellular structure helps to ret~in t~e integrity of the electrically conductivelmaterial even when the composite is subjected to considerable l compression or deformation.
The open-celled cellular structure is preferably provided by applying electricalIy conductive material to the interior surface of open-celled cellular poly-meric material, which may be prepared by any convenient ,~ method, such as sintering or otherwise bonding together polymer ibres, but is preferably a foamed polymer within which membranes between adjacent cells have been removed by known techniques. Alternatively, polymer fibres already coated with the conductive material could be sintered to provide the electrically conduc-tive cellular structure.
~ .
~ ~7 9~
\ - 3 - RR2~8 The electrically conductive material may be of any kind and'in any form and applied in any way which pro-vides a level of electrical conductivity desired for the end use of a given composite, but is preferably a substantially continuous coating on the free~space defining interior surface of the cellular ~structure.
The conductive material is preferably a metal, and is preferably plated onto the polymer ~.g. by electroless plating an-d/or electroplating, preferably after suitable surface treatment of the polymerj e.g. acid etching. 1 - When the filling material is substantially electrically non-conductive, e.g. polymerlç or elasto-meric material the present invention has the advantage that the insulating filling polymer cannot disrupt the con~uctivity of the substantially continuous coating of I thelelectrically conductive material preferably present on the interior surface of the cell~ular structurè. In contrast with this, a woven or non-~oven structure of individual fibres would suffer from reduced conduc-~ tivity due to the filling polymer intruding between thefibres and increasing the electrical resistance at the inter-fibre contact points.
From this aspect, therefore, the present invention provides an electrically conductive composite material comprising (a) an open-celled cellular structure of polymeric material having electrically conductive material on at least its interior surface defining the cellular free space, and 79~2 ~ _ 4 _ RK288 , , ~b) substantially solid substantially electrically non-conductive material overlying the electrically conductive material.
, The non-conductive material preferably substantially fills the cellular free space to provide a composite having the features hereinbefore described.
, ~ The cell size of the cellular structure influences ; the flexibility and conductivity of the composite, an average ceIl diameter within the range from 0.01 to 10 ~millimetres preferably 0.2 to 2 millimetres, being pre-ferred, and the cellular free space preferably compri-ses from 45 to 99% by volume of the unfilled cellular structure. ~
I I I ~
Polymeric illing material may be formed ln' situ - --by polymerisatio~ of a monomer or oligomer withi~ the cellular ~tructure, or may belintroduced thèreinto~in a flowahle state and thereafter solidified, e.g. by soli- i dification of molten poly~er or by drying of a ~olution or dispersion of polymer in a fluid carrier, or by cross-linking a flowable polymer.
The materials u~ed in the composite may be selected according to the end use properties desired.
The polymer which forms the celIular structure carrying the electrically conductive ~aterial may any suitable cellular poly~er, for example polyester, polyamide, polyurethane, polyolefins.
.~ .
The electrically conductive material may be an inherently conductive polymer e.g. polyacetylene or polypyrrole, or a polymer filled with electrically con-I
1, ,~:
~Z~9~
ductive filler to a level giving acceptable conductivity, but is preferably a metal, e. g. copperr silver, nickelr cobalt or tin/lead alloys.
The filling material may be chosen to provide the desired properties, and may for some purposes be a metallic composition such as solder or an electrically conduGtive polymer or polymer composltion. Substantially electrically non-conductive polymers are, howeverr preferredr elastomers being especially useful for environmental sealing purposes, e. g. in cable feedthrough glands. Suitable elastomers include, for example polyurethanes, silicone rubber, polysulphides, polyamides. Other potentially useful fillings include hot melt adhesives, gels, thermoplastics, epoxies and other thermosetting composit:Lons, and system~ which are polymerisable in situ within the cellular structure.
The composite materials in accordance with ~he invention may be used in areas other than the production of feedthrough ~lands. For example they may be incorporated within a dimensionally recoverable article, e. gO a heat-shrinkable article, ln order to provide electromagnetic shielding for the articls and the enclosed equlpment. Electrically shielded heat-shrinkable articles are described in Britlsh Patent Application No. 2,113,022A published July 27, 1983.
Referring to the drawings, Figure 1 shows one type of gland used in ships, industrial plants, public buildings, power stations, etc.
The appearance of the electrically conductive composi~e can readily be imagined from the preceding descrlption without the lZlg7~
6 27~65-136 need to resort to drawinys. Use in cable feedthrough glands of electrically conductive composites having the advantageous cellular structure instead of fibrous or par~iculate conductive material i~ new, and will therefore now be described with reference to the accompanying drawings. In this aspect, the invention provides a composite material according to claim 3, wherein the non-conductive materlal substantially fills the cellular ~ree space. The composite seal is preferably as hereinhefore described, although for some purposes less than complete filllng and/or ~illings other than polymers may be desirable.
The various cables 10 are passed through the gland frame ll in wall 1, and to complete the installatlon palrs of rubber blocks 12 with semi circular channels are fltted around each cable to ~orm a rectangular matrix filllng the ~rame. Blanking blocks 6 fill any unused spaces. The whole assembly is then compres ed mechanically in a plane at right angles to the cables by compression bolt 13 acting on compression assembly 14, 15, 16, 17 whlch is slidable within the frame ll, thus closing any gaps in the ma~rix and olamping and sealing on to the cable jackets.
So tha~ the rubber blocks according to the present invention will electrically connect the outer braided screens o~
the cables to the ~land frame, cables with an external jacket over the screen may have the outer insulation cut away locally, "centre-stripped", to expose the screen.
-` ~26'79~L2 \ - 7 - RR288 The requirements of low toxicity/low flammability/
fire integrity/electrical conductivity can be met by the present invention. Conductivi1:y is the biggest problem in the known glands, a st,~ndard requirement being 0.3 ohms maximum resistance between the cable braid and the gland frame. Conductive rubbers are too ; resistive, unless very high filler loadings are used, e.g. silver!which is expensive. One approach known prior-to the present invention is believed to have been to incorporate spring-loaded metal contacts in the rubber blocks, which is undesirably complicated.-I ~11 ` ' .
Figure 2 shows a preferred "sandwich~ design~for the rubber blocks using the composite material of the present invention. In this form, the conductive com-posite forms the central part ~21/of the block 22, with plain polymer end portions 23, preferably of the same polymer as fills `the c!ellular ~tructure of the com-posite, e.gl silicone ~ubber. i In this, and other, constructions the cellular structure ineed not necessarily be c~mpletely filled, and other forms of electrically cbnductive cellular structure such as sin-tered metal fibres could be used if the disadvantages of greater weight and rigidity can be tolerated.
The starting point for the preferred block is a very highly expanded polyether foam, so highly expanded as to be "skeletaln, i.e. a very open celled structure.
Electroless platiny with an adherent coating of nickel renders it highly conductive, and it can then be filled with silicone rubber by pouring the liquid silicone rubber into it and curing it. The~result is effec-tively highly conductive silicone rubber with ~inimum loss of rssilience and very low but very effective metal content.
I
7~
The preferred "sandwich" of this material between plain silicone rubber end portions as described above in use allows the conduct,ive part to contact the exposed cable braid and the plain end sections to seal against and support the cable jacket. Such a system has all the practical advantages of the known gland system with the added benefit of EMI shielding.
The use ~f our material, because it is slo conduc-tive allows an advantageously thin conductivé part in the "sandwichq which makes up the preferred gland blocks. This .lèaves plenty of fire resistant rubber at the ends. A less conductive sysjtem would mean less room for fire resistant rubber ~or dictate thicker blocks.
I , . .
. .
. .
, ,
~ he composite material according to this invention is able to provide a substantially continuous three-- dimensional network of the electrically conductive material giving good cvnductivity while minimising the amount of metal present in the composite, since a thin layer of the conductive material on t~e cell-defining interior surface of the polymer structure will suffice.
Because the conductive material is thus minimised, the composite is enabled to retain much of the charact~r of i thP filling material. In preferred forms, where the filling is flexible e.g. elastomeric, the cellular structure and the conductive material, (usual~y metal), can be sufficiently flexible for the composite to be 6argely e~astomeric in character. The filling material - filiing ~he cellular structure helps to ret~in t~e integrity of the electrically conductivelmaterial even when the composite is subjected to considerable l compression or deformation.
The open-celled cellular structure is preferably provided by applying electricalIy conductive material to the interior surface of open-celled cellular poly-meric material, which may be prepared by any convenient ,~ method, such as sintering or otherwise bonding together polymer ibres, but is preferably a foamed polymer within which membranes between adjacent cells have been removed by known techniques. Alternatively, polymer fibres already coated with the conductive material could be sintered to provide the electrically conduc-tive cellular structure.
~ .
~ ~7 9~
\ - 3 - RR2~8 The electrically conductive material may be of any kind and'in any form and applied in any way which pro-vides a level of electrical conductivity desired for the end use of a given composite, but is preferably a substantially continuous coating on the free~space defining interior surface of the cellular ~structure.
The conductive material is preferably a metal, and is preferably plated onto the polymer ~.g. by electroless plating an-d/or electroplating, preferably after suitable surface treatment of the polymerj e.g. acid etching. 1 - When the filling material is substantially electrically non-conductive, e.g. polymerlç or elasto-meric material the present invention has the advantage that the insulating filling polymer cannot disrupt the con~uctivity of the substantially continuous coating of I thelelectrically conductive material preferably present on the interior surface of the cell~ular structurè. In contrast with this, a woven or non-~oven structure of individual fibres would suffer from reduced conduc-~ tivity due to the filling polymer intruding between thefibres and increasing the electrical resistance at the inter-fibre contact points.
From this aspect, therefore, the present invention provides an electrically conductive composite material comprising (a) an open-celled cellular structure of polymeric material having electrically conductive material on at least its interior surface defining the cellular free space, and 79~2 ~ _ 4 _ RK288 , , ~b) substantially solid substantially electrically non-conductive material overlying the electrically conductive material.
, The non-conductive material preferably substantially fills the cellular free space to provide a composite having the features hereinbefore described.
, ~ The cell size of the cellular structure influences ; the flexibility and conductivity of the composite, an average ceIl diameter within the range from 0.01 to 10 ~millimetres preferably 0.2 to 2 millimetres, being pre-ferred, and the cellular free space preferably compri-ses from 45 to 99% by volume of the unfilled cellular structure. ~
I I I ~
Polymeric illing material may be formed ln' situ - --by polymerisatio~ of a monomer or oligomer withi~ the cellular ~tructure, or may belintroduced thèreinto~in a flowahle state and thereafter solidified, e.g. by soli- i dification of molten poly~er or by drying of a ~olution or dispersion of polymer in a fluid carrier, or by cross-linking a flowable polymer.
The materials u~ed in the composite may be selected according to the end use properties desired.
The polymer which forms the celIular structure carrying the electrically conductive ~aterial may any suitable cellular poly~er, for example polyester, polyamide, polyurethane, polyolefins.
.~ .
The electrically conductive material may be an inherently conductive polymer e.g. polyacetylene or polypyrrole, or a polymer filled with electrically con-I
1, ,~:
~Z~9~
ductive filler to a level giving acceptable conductivity, but is preferably a metal, e. g. copperr silver, nickelr cobalt or tin/lead alloys.
The filling material may be chosen to provide the desired properties, and may for some purposes be a metallic composition such as solder or an electrically conduGtive polymer or polymer composltion. Substantially electrically non-conductive polymers are, howeverr preferredr elastomers being especially useful for environmental sealing purposes, e. g. in cable feedthrough glands. Suitable elastomers include, for example polyurethanes, silicone rubber, polysulphides, polyamides. Other potentially useful fillings include hot melt adhesives, gels, thermoplastics, epoxies and other thermosetting composit:Lons, and system~ which are polymerisable in situ within the cellular structure.
The composite materials in accordance with ~he invention may be used in areas other than the production of feedthrough ~lands. For example they may be incorporated within a dimensionally recoverable article, e. gO a heat-shrinkable article, ln order to provide electromagnetic shielding for the articls and the enclosed equlpment. Electrically shielded heat-shrinkable articles are described in Britlsh Patent Application No. 2,113,022A published July 27, 1983.
Referring to the drawings, Figure 1 shows one type of gland used in ships, industrial plants, public buildings, power stations, etc.
The appearance of the electrically conductive composi~e can readily be imagined from the preceding descrlption without the lZlg7~
6 27~65-136 need to resort to drawinys. Use in cable feedthrough glands of electrically conductive composites having the advantageous cellular structure instead of fibrous or par~iculate conductive material i~ new, and will therefore now be described with reference to the accompanying drawings. In this aspect, the invention provides a composite material according to claim 3, wherein the non-conductive materlal substantially fills the cellular ~ree space. The composite seal is preferably as hereinhefore described, although for some purposes less than complete filllng and/or ~illings other than polymers may be desirable.
The various cables 10 are passed through the gland frame ll in wall 1, and to complete the installatlon palrs of rubber blocks 12 with semi circular channels are fltted around each cable to ~orm a rectangular matrix filllng the ~rame. Blanking blocks 6 fill any unused spaces. The whole assembly is then compres ed mechanically in a plane at right angles to the cables by compression bolt 13 acting on compression assembly 14, 15, 16, 17 whlch is slidable within the frame ll, thus closing any gaps in the ma~rix and olamping and sealing on to the cable jackets.
So tha~ the rubber blocks according to the present invention will electrically connect the outer braided screens o~
the cables to the ~land frame, cables with an external jacket over the screen may have the outer insulation cut away locally, "centre-stripped", to expose the screen.
-` ~26'79~L2 \ - 7 - RR288 The requirements of low toxicity/low flammability/
fire integrity/electrical conductivity can be met by the present invention. Conductivi1:y is the biggest problem in the known glands, a st,~ndard requirement being 0.3 ohms maximum resistance between the cable braid and the gland frame. Conductive rubbers are too ; resistive, unless very high filler loadings are used, e.g. silver!which is expensive. One approach known prior-to the present invention is believed to have been to incorporate spring-loaded metal contacts in the rubber blocks, which is undesirably complicated.-I ~11 ` ' .
Figure 2 shows a preferred "sandwich~ design~for the rubber blocks using the composite material of the present invention. In this form, the conductive com-posite forms the central part ~21/of the block 22, with plain polymer end portions 23, preferably of the same polymer as fills `the c!ellular ~tructure of the com-posite, e.gl silicone ~ubber. i In this, and other, constructions the cellular structure ineed not necessarily be c~mpletely filled, and other forms of electrically cbnductive cellular structure such as sin-tered metal fibres could be used if the disadvantages of greater weight and rigidity can be tolerated.
The starting point for the preferred block is a very highly expanded polyether foam, so highly expanded as to be "skeletaln, i.e. a very open celled structure.
Electroless platiny with an adherent coating of nickel renders it highly conductive, and it can then be filled with silicone rubber by pouring the liquid silicone rubber into it and curing it. The~result is effec-tively highly conductive silicone rubber with ~inimum loss of rssilience and very low but very effective metal content.
I
7~
The preferred "sandwich" of this material between plain silicone rubber end portions as described above in use allows the conduct,ive part to contact the exposed cable braid and the plain end sections to seal against and support the cable jacket. Such a system has all the practical advantages of the known gland system with the added benefit of EMI shielding.
The use ~f our material, because it is slo conduc-tive allows an advantageously thin conductivé part in the "sandwichq which makes up the preferred gland blocks. This .lèaves plenty of fire resistant rubber at the ends. A less conductive sysjtem would mean less room for fire resistant rubber ~or dictate thicker blocks.
I , . .
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Claims (16)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS
FOLLOWS:
1. An electrically conductive composite material comprising (a) an open-celled cellular structure of polymeric material having electrically conductive material on at least its interior surface defining the cellular free space, and (b) substantially solid filling material substantially filling at least part of the cellular free space.
2. A composite material according to claim 1, wherein the filling material is substantially electrically non-conductive.
3. An electrically conductive composite material comprising (a) an open-celled cellular structure of polymeric material having electrically conductive material on at least its interior surface defining the cellular-free space, and (b) substantially solid substantially electrically non-conductive material overlying the electrically conductive material.
4. A composite material according to claim 3, wherein the non-conductive material substantially fills the cellular free space.
5. A composite material according to claim 1 or claim 3, wherein the average cell diameter of the cellular structure is within the range from 0.01 to 10 milli-metres, preferably from 0.2 to 2 millimetres.
6. A composite material according to claim 1 or claim 3, wherein the cellular free space comprises 45 to 99%
of the unfilled cellular structure.
.
of the unfilled cellular structure.
.
7. A composite material according to claim 1, wherein the electrically conductive material is a substantially continuous coating on the interior surface of the cellular structure.
8. A composite material according to claim 7, wherein the electrically conductive coating is a metal coating.
9. A composite material according to claim 8, wherein the metal coating has been plated on the polymeric material.
10. A composite material according to claim 1, wherein the material within the cellular free space comprises polymeric material.
11. A composite material according to claim 10 wherein the polymeric material within the cellular free space has been formed in situ by polymerisation of a monomer or oligomer.
12. A composite material according to claim 1 or claim 3, wherein the material within the cellular free space has been introduced thereinto in a molten state and subsequently solidified.
13. A composite material according to claim 1 or claim 3, wherein the material within the cellular free space comprises an elastomer.
14. A cable feedthrough gland for use with one or more shielded cables, the gland comprising (a) a seal of electrically conductive composite material comprising an open-celled cellular struc-ture of electrically conductive material whose cellular free space contains substantially solid material other than the said electrically conduc-tive material, and (b) an electrically conductive housing through which the cable(s) will extend in use, the seal being capable of arrangement in the housing substan-tially to seal the space between the housing and the cable(s) when extending through the housing and to connnect the cable sheath(s) electrically to the housing by contact of the electrically con-ductive material of the seal with the sheath(s) and the housing.
15. A gland according to claim 14, wherein the seal comprises a composite material according to any of claims 1 or 3.
16. A dimensionally recoverable article which is pro-vided with an electromagnetic shield comprising a com-posite material as claimed in claim 1 or claim 3.
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Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB858528808A GB8528808D0 (en) | 1985-11-22 | 1985-11-22 | Electrically conductive composite material |
| GB8528808 | 1985-11-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1267942A true CA1267942A (en) | 1990-04-17 |
Family
ID=10588626
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000523507A Expired - Fee Related CA1267942A (en) | 1985-11-22 | 1986-11-21 | Electrically conductive composite material |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US4764422A (en) |
| EP (1) | EP0223615B1 (en) |
| JP (1) | JPH0777087B2 (en) |
| AT (1) | ATE61690T1 (en) |
| CA (1) | CA1267942A (en) |
| DE (1) | DE3678104D1 (en) |
| GB (1) | GB8528808D0 (en) |
Families Citing this family (32)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3826469A1 (en) * | 1988-08-04 | 1990-02-08 | Roehm Gmbh | HARD FOAM AS A CORE MATERIAL FOR LAYING MATERIALS |
| JPH02117932A (en) * | 1988-10-26 | 1990-05-02 | Kitagawa Kogyo Kk | Electrically conductive elastic unit |
| US5388518A (en) * | 1988-11-10 | 1995-02-14 | Composite Materials Technology, Inc. | Propellant formulation and process |
| US6746770B1 (en) * | 1989-05-26 | 2004-06-08 | Internatonal Business Machines Corporation | Electrically conductive and abrasion/scratch resistant polymeric materials, method of fabrication thereof and uses thereof |
| DE4305071A1 (en) * | 1992-09-29 | 1994-08-25 | Klein Guenther Industriebedarf | Packing system for the passage of cables through screen walls |
| US5431998A (en) * | 1993-05-14 | 1995-07-11 | Lockheed Corporation | Dimensionally graded conductive foam |
| US5524908A (en) * | 1994-09-14 | 1996-06-11 | W. L. Gore & Associates | Multi-layer EMI/RFI gasket shield |
| US6169160B1 (en) | 1996-09-26 | 2001-01-02 | Union Camp Corporation | Cable protectant compositions |
| NL1008787C2 (en) * | 1998-04-02 | 1999-10-05 | R & H Systems B V | Method for passing electrical cables. |
| US6339536B1 (en) | 1999-11-10 | 2002-01-15 | Dell Usa, L.P. | I/O shield bracket assembly |
| US6309742B1 (en) | 2000-01-28 | 2001-10-30 | Gore Enterprise Holdings, Inc. | EMI/RFI shielding gasket |
| US6469244B1 (en) | 2000-06-27 | 2002-10-22 | Cisco Technology, Inc. | EMI cable passthrough shield |
| DE10150075A1 (en) * | 2001-10-10 | 2003-04-17 | Roxtec Ingenieur Gmbh | Module for a sealed passage for cables/pipes, through constructions, has a lateral recess around its outer sealing surfaces with at least one drilling to the interior to test the hermetic sealing |
| EP1311146A3 (en) * | 2001-11-07 | 2005-11-23 | Alcatel | Electrical shield |
| CN101300916B (en) * | 2005-11-01 | 2011-06-15 | 莱尔德技术股份有限公司 | Emi vent panels including electrically-conductive porous substrates and meshes |
| US8328026B2 (en) * | 2007-02-22 | 2012-12-11 | Tellabs Operations, Inc. | Apparatus and method for configuring a dual rack-mountable chassis |
| SE533744C2 (en) | 2009-02-04 | 2010-12-21 | Roxtec Ab | Pipe or cable entry with modularized modules |
| JP5503229B2 (en) * | 2009-09-08 | 2014-05-28 | 株式会社古河テクノマテリアル | Fire prevention structure, construction method of fire prevention structure and method of adding cable to fire prevention structure |
| US8243470B2 (en) | 2010-03-31 | 2012-08-14 | International Business Machines Corporation | Ferrite inductors integrated within top-mounted input/output cable port assembly of an electronics rack |
| US8243469B2 (en) | 2010-03-31 | 2012-08-14 | International Business Machines Corporation | Ferrite inductors integrated within input/output cable port assembly of an electronics rack |
| WO2012088565A1 (en) * | 2011-01-01 | 2012-07-05 | Cabscape Holdings Pty Ltd | Seals to barrier penetrations |
| US9419424B2 (en) * | 2011-08-24 | 2016-08-16 | Abb Schweiz Ag | Switchgear bus support bushing structure |
| US9739402B2 (en) | 2013-03-04 | 2017-08-22 | Eaton Corporation | Electrically conductive seals for fluid conveyance systems |
| US9204580B2 (en) | 2013-12-23 | 2015-12-01 | International Business Machines Corporation | Movable shielded cable egress |
| US9313935B2 (en) * | 2014-04-09 | 2016-04-12 | International Business Machines Corporation | Universal/portable cable support and EMI reduction bar |
| SE539322C2 (en) * | 2015-11-18 | 2017-07-04 | Roxtec Ab | Transition and module |
| DE202016103494U1 (en) * | 2016-06-30 | 2017-07-06 | Conta-Clip Verbindungstechnik Gmbh | Cable wall bushing and kit |
| US10700502B2 (en) * | 2016-11-02 | 2020-06-30 | RPH Intellectual Holdings, LLC | Wall penetration panel |
| DE202019002833U1 (en) * | 2019-07-09 | 2020-07-16 | Kuka Deutschland Gmbh | Cable entry for a control cabinet |
| DE202019105325U1 (en) * | 2019-09-25 | 2021-01-06 | Conta-Clip Verbindungstechnik Gmbh | Slide-in component and kit for a cable wall duct |
| SE543838C2 (en) * | 2019-12-19 | 2021-08-10 | Roxtec Ab | Transit for passing at least one cable and/or at least one metallic pipe |
| SE2150956A1 (en) * | 2021-07-16 | 2022-12-27 | Mct Brattberg Ab | Pressure test insert and frame |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1235236A (en) * | 1958-09-30 | 1960-07-01 | Friemann & Wolf Gmbh | Process for the manufacture of electrodes, in particular for alkaline accumulators |
| DE1671761A1 (en) * | 1967-09-15 | 1972-01-27 | Bayer Ag | Electrodes with a large surface area and low weight |
| US3707401A (en) * | 1968-11-12 | 1972-12-26 | Ethyl Corp | Plastic coated metallic foams |
| DE2204752A1 (en) * | 1972-02-02 | 1973-08-23 | Deutsche Automobilgesellsch | Nickel hydroxide electrodes prodn - by multistage impregnation of fibrous skeleton, with intermediate charge/discharge |
| US4496627A (en) * | 1981-11-25 | 1985-01-29 | Fujimori Kogyo Co., Ltd. | Electrical conductive foam beads and molded electrical conductive foamed articles obtained therefrom |
| JPS6088500A (en) * | 1983-10-21 | 1985-05-18 | 株式会社ブリヂストン | Gasket for radio wave shield and method of producing same |
-
1985
- 1985-11-22 GB GB858528808A patent/GB8528808D0/en active Pending
-
1986
- 1986-11-20 AT AT86309103T patent/ATE61690T1/en not_active IP Right Cessation
- 1986-11-20 DE DE8686309103T patent/DE3678104D1/en not_active Expired - Fee Related
- 1986-11-20 EP EP86309103A patent/EP0223615B1/en not_active Expired - Lifetime
- 1986-11-21 CA CA000523507A patent/CA1267942A/en not_active Expired - Fee Related
- 1986-11-21 US US06/933,459 patent/US4764422A/en not_active Expired - Fee Related
- 1986-11-22 JP JP61279531A patent/JPH0777087B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| EP0223615A3 (en) | 1988-01-07 |
| EP0223615B1 (en) | 1991-03-13 |
| ATE61690T1 (en) | 1991-03-15 |
| EP0223615A2 (en) | 1987-05-27 |
| JPH0777087B2 (en) | 1995-08-16 |
| JPS62150601A (en) | 1987-07-04 |
| US4764422A (en) | 1988-08-16 |
| DE3678104D1 (en) | 1991-04-18 |
| GB8528808D0 (en) | 1985-12-24 |
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| Date | Code | Title | Description |
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| MKLA | Lapsed |