Conductive Elastomers (ECE's)
Electrically conductive elastomers for EMI shielding are highly loaded EPDM, silicone and fluorosilicone. By loading the elastomer with various conductive fillers, it produces an conductive elastomer with an extremely low contact resistance conductive and environmental seal between mating surfaces. We use EPDM, silicone, or fuel resistant Fluorosilicone elastomers along with highly conductive metal fillers because this produces a very efficient EMI gasket which also has excellent environmental sealing characteristics.
The various conductive fillers selected for use in conductive elastomers are chosen so the best galvanic compatibility protection can be provided, whilst also the lowest contact resistance between corresponding surfaces is achieved. This also enables a conductive elastomer to be selected in order to suit the broadest span of applications.
High performance conductive elastomers were developed mainly for shielding military and aerospace applications, but now, lower cost fillers make conductive elastomers much more widely used in the commercial sector.
Conductive elastomers are used where environmental and EMI shielding is required but space constraints or stringent environmental protection necessitates a small cross section profile. Often extruded conductive elastomers are fitted into a groove or channel.
Our electrically conductive elastomers for EMI shielding are designed to meet the requirements outlined for the MIL-G-83528 specification.
Conductive Elastomer Materials
|Elastomer||Silicone||Fire Retardant Silicone||Fluoro- silicone||Silicone||Fluoro- silicone||Silicone||Fluoro- silicone||Silicone||Fluoro- silicone||Silicone||Fluoro- silicone||Silicone||Fluoro- silicone|
|Conductive Filler||Ni/C||Ni/C||Ni/C||Ag/Al||Ag/Al||Passivated Ag/Al||Passivated Ag/Al||Ag/Cu||Ag/Cu||Ni||Ni||Ni/Al||Ni/Al|
|Volume Resistivity MIL-DTL 83528 (ohm-cm, max.)||0.1||0.05||0.3||0.001||0.005||0.001||0.005||0.0009||0.01||0.1||0.1||0.08||0.03|
|Hardness (Shore A)||30-65 (Standard 65)||50-80 (Standard 60)||60||65||70||65||70||65||75||65||70||68||68|
|Tensile Strength (psi)||240||225||150||240||330||240||330||240||180||200||180||200||200|
|Tear “B” (ppi)||60||45||70||38||-||38||-||45||35||40||40||50||50|
|Thermal Conductivity (W/mK)||-||-||-||-||-||-||-||-||-||-||-||1.6||-|
|Operating Temperature||-55°C - 200°C||-55°C - 200°C||-60°C - 220°C||-60°C - 220°C||-60°C - 220°C||-60°C - 220°C||-60°C - 220°C||-60°C - 220°C||-55°C - 125°C||-60°C - 220°C||-60°C - 220°C||-60°C - 220°C||-60°C - 220°C|
|Shielding Effectiveness 20MHZ-10GHZ||>113 dB||>113||>117||>114||>125||>114||>125||>111||>108||>106||>103||>110 dB||>112 dB|
|Galvanic Corrosion 168 Hour Salt Spray||-||-||-||-||-||-||-||-||-||-||-||0.0008||-|
|Meets ASTM E595||Yes||-||-||-||-||-||-||-||-||-||-||-||-|
|UL-94 Flammability Rating||-||V0||-||-||-||-||-||-||-||-||-|
Conductive Elastomer Availability
- This material is available as sheets, extrusion, O-rings, die cut gaskets and moulded components.
- Some materials are available on rolls
- Fire retardant UL94 V-0 material available
- Low outgassing (ASTM E595) material available
- A reinforced layer can be moulded into the sheets to reinforce the gasket material
- For custom die-cut gaskets, please submit a drawing of the gasket and the type of material required
- Designed to meet the requirements of MIL-G-83528 specification.
Our electrically conductive elastomers for EMI shielding are available in sheet form, from 0.3mm thick and to any size you require up to 610mm x 670mm. They are also available with a reinforced interlayer with the thinnest sheet being 0.8mm thick
A wide range of conductive elastomer cross-sections are available. Solid and hollow round, solid and hollow ‘D’, ‘U’ channels, square/rectangular strip as well as custom sections. Hollow ‘O’ and ‘D’ sections are generally used in applications where lower compression force is required or a greater tolerance range must be allowed for.
Gasket sections can be supplied in on the roll, in cut lengths or joined to form gaskets. Extruded conductive elastomer profiles can be joined to form rings e.g. ‘o’ rings, picture frames or more complicated shapes. This is the most efficient means of producing gasket sections or gaskets using conductive elastomers
Solid round sections are available from 0.8mm upwards in increments from 0.1mm
Hollow round sections are available with a 1.2mm (outside diameter) upwards in increments of 0.1mm.
Vulcanised or Moulded O-Rings
Conductive elastomer O-rings can be manufactured by either extruding and jointing or compression moulding starting with an internal diameter of 10mm.
The o-rings are jointed using vulcanising compound to maintain electrical connectivity, or they can be manufactured using compression moulding.
The o-rings are available in all materials, fluorosilicone and silicone and other material types too.
Preform and/or Die Cut
This method produces flat gaskets using a method that reduces waste and cost. The material is moulded as a sheet or picture frame and then the gaskets are punched out. This allows economical production of parts, saving material in the case of larger gaskets and enabling many smaller parts to be punched from a single moulding. Other features can also be moulded into the gaskets such as ridges or extra seals.
This is generally the preferred method to produce connector gaskets and other flat seals. Compression limitation can also be included in these gaskets.