View Specsconductive elastomer gaskets overview

EMI Materials Introduction

- Availability

- Design Flexibility

- Cost Effectiveness

- Proven Performance

…just four of the reasons why conductive elastomer gaskets are so often the right EMI shielding solution! Once used mainly to shield critical defense and aerospace electronic systems, Parker Chomerics conductive elastomers have become the progressive choice for packaging designers of consumer, telecommunications, business, industrial equipment, automotive, medical devices and much more.

Conductive elastomers are reliable over the life of the equipment. The same gasket is both an EMI shield and an environmental seal. Elastomer gaskets resist compression set, accommodate low closure force, and help control airflow. They’re available in corrosion-resistant and flameresistant grades. Their aesthetic advantages are obvious

Almost any elastomer profile can be extruded or custommolded with modest tooling costs and short lead times for either prototypes or large orders. Parker Chomerics can also take a customer-supplied design and deliver finished parts. Parker Chomerics offers hundreds of standard molded and extruded products. Molded products provide moisture/pressure sealing and EMI/EMP shielding when compressed properly in seals, flanges, bulkheads, and other assemblies. Extrusions provide similar benefits and are also readily lathe-cut into washers, spliced, bonded, kiss-cut, or die-cut to reduce installation labor and to conserve material, resulting in a cost-effective alternative to other methods of EMI shielding and environmental sealing.

 

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Quick Reference Guide for Selecting Conductive Elastomers - Typical Commercial and Military Applications
(M) = Molded only, (E) = Extruded only
Material Filler Binder Shielding Corrosion
(on Aluminum)
MIL-DTL-83528
CHO-SEAL 6502 Nickel-Aluminum Silicone -----
CHO-SEAL 6503 Nickel-Aluminum Fluorosilicone -----
CHO-SEAL1298 Silver-Aluminum Fluorosilicone Type D
CHO-SEAL 1285 Silver-Aluminum Silicone Type B
CHO-SEAL 1287 Silver-Aluminum Fluorosilicone Type D
CHO-SEAL 1215 Silver-Copper Silicone Type A
CHO-SEAL 1217 Silver-Copper Fluorosilicone Type C
CHO-SEAL S6305 Nickel-Graphite Silicone -----
CHO-SEAL 6370 Nickel-Graphite Silicone -----
CHO-SEAL 6371 Nickel-Graphite Silicone -----
CHO-SEAL 6308 Nickel-Graphite Silicone -----
CHO-SEAL 6330(E) Nickel-Graphite Silicone -----
CHO-SEAL L6303 Nickel-Graphite Fluorosilicone -----
CHO-SEAL 1350 Silver-Glass Silicone Type M*
CHO-SEAL 1310(M) Silver-Glass Silicone -----
CHO-SEAL 1273 Silver-Copper Silicone -----
CHO-SEAL 1270(M) Silver-Copper Silicone -----

 

 


 

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Quick Reference Guide for Selecting Conductive Elastomers - Typical Commercial and Military Applications
(M) = Molded only, (E) = Extruded only
Material Filler Binder Shielding Corrosion
(on Aluminum)
MIL-DTL-83528
CHO-SEAL 1224(M) Silver Silicone Type E
CHO-SEAL 1221(M) Silver Fluorosilicone Type F
CHO-SEAL 1401 Silver Silicone Type J
CHO-SEAL 1239(M) Silver-Copper Silicone/Cu Mesh Type G
CHO-SEAL 1212(M) Silver-Copper Silicone/Cu Mesh Type K
CHO-SEAL 6435(M) Silver-Nickel EPDM -----
CHO-SEAL 6307(M) Nickel-Graphite EPDM -----
CHO-SEAL 6452(E) Nickel-Graphite EPDM -----
CHO-SEAL 6460(M) Nickel-Aluminum EPDM -----
CHO-SEAL V6433(M) Silver-Nickel Fluoro/Fluorocarbon -----
CHO-SEAL 1224(M) Carbon Silicone -----

 

 


 

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CHO-SEAL®CONDUCTIVE ELASTOMERS

Over the years, Parker Chomerics has developed and enhanced virtually every aspect of conductive elastomer materials technology, from the earliest silver and silver-plated copper filled silicones, to the latest and more cost-effective nickel-plated aluminum and nickel-plated graphite composites. Today we offer the most comprehensive selection and highest quality products available.

Each conductive elastomer consists of a silicone, fluorosilicone, EPDM or fluorocarbonfluorosilicone binder with a filler of pure silver, silver-plated copper, silver-plated aluminum, silverplated nickel, silver-plated glass, nickel-plated graphite, nickelplated aluminum or unplated graphite particles. The development of these composites is the result of decades of research and testing, both in the laboratory and in the field. Our proprietary filler powder technology allows us to carefully control the composition, size, and morphology of the conductive particles. Their precise, uniform dispersion within the resinous binders produces materials with stable and consistent electrical and physical properties

Parker Chomerics’ conductive elastomers feature excellent resistance to compression set over a wide temperature range, resulting in years of continuous service. In addition to EMI shielding, these materials can provide an environmental or pressure seal if required.

For those materials containing silver, both packaging and storage conditions should be similar to those for other silver-containing components, such as relays or switches. They should be stored in sheet plastic, such as polyester or polyethylene, and kept away from sulfur-containing materials, such as sulfur-cured neoprene, cardboard, etc. To remove dirt, clean the elastomer with water or alcohol containing mild soap (do not use aromatic or chlorinated solvents). Shelf life of these conductive elastomers without the presence of pressure sensitive adhesive (PSA) is indefinite. Shelf life of the PSA is 12 months from date of manufacture. Refer to page 30 for Applications detailed guidance on PSA systems.

The tables outline the properties and specification limits of Parker Chomerics’ conductive elastomers. These materials are produced in a virtually unlimited variety of molded, die-cut and extruded shapes and sizes. Our Applications Engineering Department is very accessible, and ready to assist with material selection and gasket design. We welcome your inquiry

 


 

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MATERIAL SELECTION

The Parker Chomerics array of conductive elastomers offers true flexibility in selecting the appropriate material for a specific application on the basis of cost and level of attenuation required. Price varies directly with shielding performance.

For some military/aerospace applications, users of conductive elastomer gaskets consider specifying materials that meet MIL-DTL-83528 where appropriate but note that newer materials may not yet be included in that specification, e.g., nickel-plated aluminum filled elastomers. To avoid the risk of system EMI or environmental seal failure, any change in conductive elastomer seal supplier (including MIL-DTL-83528 QPL suppliers) should be preceded by thorough system qualification testing.

 


 

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UL 94 V-0 RATED MATERIALS

Chomerics introduced the first conductive elastomer gasket material with a UL 94 V-0 rating.

Since that time, Chomerics now has a selection of UL 94 V-0 rated gasket materials including CHO-SEAL 6370, 6371, 1273, S6305 and 1310.

CHO-SEAL gasket materials are rated at UL 94 V-0 down to a thickness of 0.013 Inch (0.33 mm). Actual thickness for each certified material, and specific conditions of use can be found in UL File #OCDT2.E140244 under Insulating Devices and Materials – Components. CHO-SEAL materials certified by UL for use in Canada can be found in UL File OCDT8.E140244. For UL Certification files, please visit www.ul.com.

 

 


 

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Conductive Elastomer Applications

In general, certain types of Parker’s conductive elastomers are specified more often for military/aerospace applications or for commercial applications. However, there is a considerable overlap, and our Applications Engineering department will be pleased to assist you with your product selection

 


 

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ELASTOMER PRODUCT OFFERING

Military and Commercial Products
CHO-SEAL
6502
6503 – Fluorosilicone
1298 – Fluorosilicone
1285
1287 – Fluorosilicone
1215
1217 – Fluorosilicone
S6305
6370 – Extruded only
6371 – Molded only
6308 – Extruded Only
6330 – Molded Only
L6303 – Fluorosilicone
1350
1310 – Molded Only
1273
1270 – Molded Only

Specialty Products
CHO-SEAL
1224 - Molded Only
1221 – Fluorosilicone, Molded Only
S6600 – Molded Only
1401
1239 - Molded Only
1212 – Molded Only
6435 – Molded Only
6307 – Molded Only
6452 – Extruded Only
6460 – EPDM , Molded Only
V6433 – Molded Only

Refer to ttables 6 and 7 for specific material properties and material guidelines

 


 

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168 Hour Typical Elastomers-Galvanic Compatibility Exposure to Salt Spray / Salt Fog

Substrate Filler
Nickel-Plated
Aluminum*
Passivated
Silver-Plated
Aluminum
Silver-Plated
Aluminum
Nickel-Plated
Graphite
Silver-Plated
Copper
Aluminum: 6061-T6 Conversion Coated Type I, Class 3 Finish (Hexavalent) Excellent Excellent Excellent / Good Fair Poor
Aluminum: 6061-T6 Conversion Coated Type II, Class 3 Finish (Trivalent) Excellent Excellent Good Fair Poor
Aluminum: 6061-T6 Unplated No Data Good Fair Fair/Poor Not
Recommended
Stainless Steel: 304SS, 316SS Excellent Excellent Excellent Excellent No Data
Electroless Nickel .002” thick Good Good Good Poor No Data
Magnesium Not
Recommended
Not
Recommended
Not
Recommended
Not
Recommended
Not
Recommended

504 Hour Typical Elastomers-Galvanic Compatibility Exposure to Salt Spray / Salt Fog

Aluminum: 6061-T6 Conversion Coated Type I, Class 3 Finish (Hexavalent) Excellent Good Fair Poor Not
Recommended
Aluminum: 6061-T6 Conversion Coated Type II, Class 3 Finish (Trivalent) Good Good Fair Poor Poor

 

 

 


 

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UL 94 V-0 Rated Materials

Chomerics introduced the first conductive elastomer gasket material with a UL 94 V-0 rating.

Since that time, Chomerics now has a selection of UL 94 V-0 rated gasket materials including Cho-Seal 6370, 6371, 1273, S6305 and 1310.

Cho-Seal gasket materials are rated at UL 94 V-0 down to a thickness of 0.013 Inch (0.33 mm). Actual thickness for each certified material, and specific conditions of use can be found in UL File #OCDT2.E140244 under Insulating Devices and Materials – Components. Cho-Seal materials certified by UL for use in Canada can be found in UL File OCDT8.E140244. For UL Certification files, please visit www.ul.com.

 


 

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Lightning Strike Resistance

The survivability of any system to lightning strike is dependent on specific flange design. Lightning strike testing of
CHO-SEAL 1298 gasket material has demonstrated survivability beyond 5 kA/in. Test data is available upon request.
(Request Test Report TR-34A.)

 


 

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Fluid Resistance - Harsh Environments

Table 6 lists a qualitative assessment of fluid resistance by material type. The customer is encouraged to evaluate specific materials to the requirements demanded by the application.

 

 


 

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Fluid Resistance - Common Fluids on Silicone

Table 5 illustrates the change in physical properties of CHO-SEAL S6305 after exposure to a variety of common fluids. The complete report is available from Chomerics upon request.

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Exposure of CHO-SEAL® S6305 to Common Household Fluids Tensile/Elongation in accordance with ASTM D412
Exposure Conditions: 70 hrs @ 22°C/50% RH Pre-Exposure Post-Exposure % Change
Test 1
ClearVue® Tensile [psi] 200 178 -11%
ClearVue® Elongation [%] 289 317 10%
Formula 409® Tensile [psi] 200 197 -2%
Formula 409® Elongation [%] 289 219 -24%
Windex® Tensile [psi] 200 202 1%
Windex® Elongation [%] 289 166 -43%
Test 2
Carpet Cleaner Tensile [psi] 203 207 2%
Carpet Cleaner Elongation [%] 414 443 7%
Coffee Tensile [psi] 203 211 4%
Coffee Elongation [%] 414 439 6%
Cola Tensile [psi] 203 199 -2%
Cola Elongation [%] 414 433 5%
Hairspray Tensile [psi] 203 207 2%
Hairspray Elongation [%] 414 326 -21%
Tire Cleaner Tensile [psi] 203 175 -14%
Tire Cleaner Elongation [%] 414 418 1%
Vinyl Protectant Tensile [psi] 203 172 -15%
Vinyl Protectant Elongation [%] 414 433 5%
Tap Water Tensile [psi] 203 199 -2%
Tap Water Elongation [%] 414 439 6%
Windshield Washer Solvent Tensile [psi] 203 207 2%
Windshield Washer Solvent Elongation [%] 414 418 1%

 

 


 

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Typical Elastomer Fluid Resistance
Exposure / Fluid Type Elastomer Choice
Silicone Fluorosilicone EPDM
High Temp Excellent Good Fair
Low Temp Excellent Excellent Excellent
ASTM 1 Oil Fair/Good Good Poor
Hydraulic Fluids (Phosphate Ester) Poor Poor Poor
Hydrocarbon Fuels Poor Good Excellent
Ozone, Weather Good Good Good
STB (NBC Decontamination Fluid) Poor Fair/Good Good
Dilute Acids Fair Good Good

 

 


 

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Dual Functionality Gaskets, "Co-Extruded and Co-Molded"

Co-Extruded and Co-Molded gaskets (dual gaskets with both a conductive and a non-conductive element, cured in parallel) provide additional environmental sealing and corrosion protection. Seam vulcanization ensures the long term integrity and stability of the gasket.

Co-Extruded and Co-Molded gaskets permit the cost effective use of existing flange designs, while offering attachment alternatives via the less expensive, non-conductive material. Compared to bonding and mounting separate gaskets or double-groove designs, Co-Extruded and Co-Molded gaskets offer design, cost and handling advantages.

 

NOTICE: The information contained herein is to the best of our knowledge true and accurate. However, since the varied conditions of potential use are beyond our control, all recommendations or suggestions are presented without guarantee or responsibility on our part and users should make their own tests to determine the suitability of our products in any specific situation. This product is sold without warranty either expressed or implied, of fitness for a particular purpose or otherwise, except that this product shall be of standard quality, and except to the extent otherwise stated Chomerics’ invoice, quotation, or order acknowledgement. We disclaim any and liability incurred in connection with the use of information contained herein, or otherwise. All risks of such are assumed by the user. Furthermore, nothing contained herein shall be construed as a recommendation to use any process or to manufacture or to use any product in conflict with existing or future patents covering any product or material or its use.