GORE-SHIELD® 2100 EMI Gasket Specifications

General

This specification establishes the electrical and environmental characteristics of GORE-SHIELD GS2100 Series EMI-RFI gasket material. This material consists of expanded polytetrafluoroethylene (ePTFE) that has been filled with a highly conductive carbon particle. This material is intended for use as a gasket material to suppress unwanted electromagnetic or radio frequency interference, and it also provides an excellent environmental seal. GS2100 is the DESC/Military Specified version of the GORE-SHIELD range of EMI gasket materials. It is designed to comply with military specifications such as USA Mil Spec DESC 92017 and UK DEF STAN 59-103. GS2100 exhibits superior durability and reusability in harsh environments. A space-grade version, manufactured under special clean conditions, is also available.

Material forms

GORE-SHIELD EMI/RFI gasket material is available in strip form or as a die-cut gasket. Strip gaskets are available in standard thicknesses and widths. Other thicknesses and widths are available upon request. Die-cut gaskets are manufactured to customer specifications and will be produced to standard GORE-SHIELD tolerances unless otherwise requested by the customer. GORE-SHIELD strip is supplied with conductive adhesive backing as standard.

Standard material thickness:

1.0 Applicable specifications and standards

1.1 General
The following specifications and standards apply only to the extent specified herein.

1.1.1 ASTM standard test methods

1.1.2 Military specifications and standards

1.1.3 Underwriters Laboratory Inc. test methods

1.1.4 European Space Agency specifications and standards

1.1.5 British standard specifications

2.0 Performance characteristics

2.1 General
Shipped material shall be capable of meeting the performance characteristics specified herein, when tested according to the methods stated.

2.2 Electrical performance

2.2.1 Volume resistivity
When tested per DESC 92017, Paragraph 3.5.1 or per MIL-G- 83528, Paragraph 4.6.10, with recommended load 3.45 MPa (500psi), resistivity of the material shall not exceed 1.5 ohm cm (0.25mm thick material 2.5 ohm cm). Conductivity of GORE-SHIELD improves with compression. It is important to note there is no direct link between DC resistance and RF shielding effectiveness per SAE AIR 1404 Report.

2.2.2 Shielding effectiveness
When tested per DESC 92017, Paragraph 3.5.2 or per MIL-G- 83528, 'E' field shielding effectiveness shall be equal to or greater than 100 dB from 200MHz 18GHz.

2.2.3 Electromagnetic discharge
Material charged to its maximum potential (typically less than 150 volts DC) at a temperature of 25°C and an ambient relevant humidity of 45 percent shall bleed to 100 Volts or less within 0.5 seconds upon removal from the charging potential.

2.2.4 Electromagnetic pulse (EMP) survivability
When tested in accordance with DEF STAN 59-103, the material shall be capable of withstanding induced current pulses equivalent to 16 kA per cm2 without any decrease in conductivity.

2.2.5 Reusability for EMI seal
Material to remain reusable when tested to provide at least 80dB shielding effectiveness during 10 openings/closings of gasket assembly over frequency range of 200MHz-10Gz. (MIL-G-83528).

2.3.1 Temperature range operating
The operating temperature range shall be -200°C to + 200°C exclusive of adhesive. Adhesive temperature range is 40°C to + 95°C.

2.3.2 Density/specific gravity
The density shall be 0.34 ±0.05 grams per cc when tested according to ASTM-D 1622-88 or BS903 Part A1 Method A.

2.3.3 Corrosion resistance
Conforms to DEF STAN 59-103 requirements. For longer-term corrosion protection, standard external protective coatings such as paint or silicon grease aid protection. Interfaces should be nickel-plated.

2.3.4 Flammability
Material shall meet the requirements of Underwriter's Laboratory Inc. Test UL-94V-O for flame retardency.

2.3.5 Outgassing
For the space grade version of GS2100, when tested per NASA Specification ASTM-E-595, total mass loss (TML) shall not exceed 1.0 percent (typical values are 0.53 percent TML and 0 percent CVCM). Similar results can be achieved when testing to ESA Specification PSS-01-702. When testing GS2100 Series material with a CPSA backing, it too will meet the NASA and ESA Outgassing specification. (Typical values for CPSA backed GORE-SHIELD are 0.65 percent TML and 0.02 percent CVCM). Space-qualified material must be specified at time of ordering.

2.3.6 Contaminant resistance
Complies with DESC 92017 and MIL-G-83528, remaining conductive during fluid immersion. The basic GORE-TEX™ structure of GORE-SHIELD has an ASTM classification of ASTM-F-104 (F28331), indicating that it is a fluorocarbon polymer of expanded structure. It has a maximum three percent increase in weight when used in a gasketed join and immersed in ASTM #3 oil. It has a zero percent weight increase when immersed in water. GORE-SHIELD GS2100 material will also comply with requirements of BS 3G1000, Part 2 - Section 3 Sub-section 3.12, Class A for airborne equipment. Also complies with DEF STAN 59-103 Part 3/1 Para 5.

2.3.7 Compressibility
When tested according to ASTM-F-36-88, compression rates of up to 50 percent are achievable with relatively low compression forces; (typically 1.4MPa (200 psi) for 1.5mm (.060') thick GORE-SHIELD material provides a 30 percent compression). Consult W. L. GORE for more detailed compression information.

2.3.8 Vibration resistance
Volume resistivity remains unaffected when tested according to DESC 92017 and MIL-G-83528 in levels up to 10G.

2.3.9 Water seal
Will provide a water seal in accordance with DEF STAN 59-103 Part 3 Part 3/1 Paragraph 8. Die-cut gaskets will require less closing force to achieve the water seal compared to strip material with overlapped join. Contact W. L. Gore & Associates with your requirements, as gasket design for water seal requires special attention.

2.3.10 Shelf life
Material will remain useable for up to 15 years if stored under room-temperature conditions. No special packaging is required, and no restrictions exist for storing GORE-SHIELD near sulphur-containing materials such as neoprene. This can be detrimental to silver-filled elastomer, but does not apply to GORE-SHIELD.Note: If using the CPSA backing, then the shelf life of the adhesive is limited to one year from dispatch of material, and stock rotation must be controlled.

2.3.11 Hardness
Typical Shore A hardness: 50 per ASTM-D2240.

2.3.12 Accelerated life (heat aging)
Complies with MIL-G-83528 & DEF STAN 59-103 Part 3/1 Paragraph 25 by not increasing in D.C. resistance after exposure to heat aging.

2.3.13 Mould growth
GORE-SHIELD is manufactured from ePTFE, which is an inert material and does not support mould growth per BS2011 Part 2-1J.

3.0 Integral adhesive

3.1 General
GORE-SHIELD material is supplied as standard with a conductive pressure-sensitive adhesive (CPSA) for ease of installation. Use of this adhesive may affect the electrical and environmental characteristics to some extent; therefore, the specifications contained herein do not apply to material with integral adhesive unless specifically detailed.CPSA is a pressure-sensitive acrylic adhesive. It is approximately 0.02mm (0.001') thick, with a temperature range of 40°C to +95°C. CPSA is used to facilitate installation of GORE-SHIELD EMI gasket material and should not be used as a structural adhesive.

4.0 Inspection prior to shipment

4.1 General
Inspection for delivery shall consist of visual, dimensional, and volume resistivity inspections. These inspections shall be performed on samples (or a lot, as applicable) to be selected on a random basis for a proposed shipment.