EMI gaskets with adhesive backing

Two constructions

A strip adhesive is a non-conductive acrylic tape along part of the gasket's footprint. On Parker Chomerics® extrusions the strip covers about half of the gasket's footprint, leaving the other half as bare elastomer against the flange. With that half still in contact, the maker reports that the strip leaves the resistance through the joint much as it was [1]. The same maker lists its advantages over a conductive adhesive: it holds more strongly, adds no second galvanic couple to the joint and costs less [1]. A compounder describes the same choice as a narrow non-conductive strip down the center or outer edge, against a z-axis conductive adhesive across the full width [6].

A full-width conductive adhesive is an acrylic or silicone adhesive loaded with conductive particles or fibers, so it conducts through its own thickness. The conductive acrylic the handbook lists for molded sheet is filled with silver-plated copper particles and is 1.5 mil thick [1]. Bare elastomer against the flange still gives the lower transfer impedance, a compounder notes, with a conductive adhesive in the joint measuring a little higher [7].

What adhesive does to shielding

The handbook's general guidance is that every published electrical figure for its conductive elastomers is for material without PSA, that a PSA may lower through-flange conductivity or shielding effectiveness to varying degrees, and that the gasket should be tested in the application [1]. Its 2000 edition was specific about the non-conductive adhesive then offered on sheet: it raised volume resistivity and flange resistance, and cut shielding by generally 5 to 10 dB [2]. For the thin conductive acrylic it now puts on molded sheet, the 2016 edition reports resistance through the flange and shielding essentially unchanged, and it adds that a gasket with PSA may need more than the minimum deflection [1]. For an EMI connector gasket that needs the lowest-resistance ground, the maker says not to use PSA at all [1].

The shielding effectiveness testing guide explains what a dB figure means and which fixture produced it, and the EMI gasket design guide covers deflection.

The adhesive usually sets the temperature limit

A conductive silicone gasket is rated by its maker well above room temperature; the grades and their limits are on the conductive silicone sheet page. The adhesive under it is often rated lower, so on an adhesive-backed gasket it is the adhesive's figure that has to cover your service temperature. Each row is that maker's own published figure; the table is our side-by-side of four sheets.

The shelf life matters too. The handbook gives sheet stock with PSA one year from its date of manufacture and sheet without adhesive an indefinite shelf life [1]. The failure modes guide covers how conductive gaskets age in service.

Where adhesive can and cannot go

• Extruded strips: PSA needs a flat mating surface at least 0.125 in wide, so the maker supplies it on D, P, K and rectangular sections and not on solid or hollow O strips [1]. Its PSA widths run from 0.050 to 0.500 in, with 0.125 in the smallest it advises [1].
• Molded sheet: its silicone and fluorosilicone sheets 0.020 in thick and up take the conductive acrylic; its fluorocarbon and EPDM sheets are not offered with PSA [1].
• O-rings: a round section has no flat face for adhesive, and a groove holds it instead; the conductive O-ring page covers groove notes.
• Solvents and wear: the maker does not advise PSA where solvent resistance is essential or where moving parts or traffic abuse the joint [1].
• Permanence: the maker describes PSA as an aid to initial assembly rather than a long-term means of attachment [1].

Conductive transfer tapes named on drawings

Some drawings name a conductive transfer tape rather than the gasket maker's own lamination, and the tape maker's datasheet then gives its limits. 3M 9713 is an acrylic adhesive loaded with conductive fibers, about 0.0035 in thick, that conducts through its thickness and in its plane, and 3M lists attaching EMI gaskets to cabinets among its uses [3]. 3M 9719 is the silicone-adhesive version, which bonds to silicone rubber and low-surface-energy surfaces and takes higher temperatures [4]. 3M's 2021 selection guide lists both tapes [5].

On silicone rubber, 3M gives 9719 a 90 degree peel above 20 oz/in, and it lists attaching silicone EMI gaskets to cabinets among the tape's uses [4].

Surface preparation and application

The gasket maker publishes cleaning procedures for phosphate-coated steel, conversion-coated aluminum, and stainless and mild steel: wash with a solvent until a cotton applicator shows no discoloration, let the surface dry, keep bare hands off it, and wash again if the gasket is not applied within 8 hours [1]. A portion of the liner then comes off, the gasket is pressed into place along its length, and a rubber roller goes over it with moderate pressure. Rolling harder does not help: per the maker, heavy rolling pulls the strip longer, and a strip that has been pulled longer may bond only in patches [1]. The maker puts the ideal installation room at 10 to 38 C and warns that adhesion suffers below 10 C; 3M gives 15 to 38 C for its 9713 tape and also advises against applying it below 10 C [1][3]. 3M adds that adhesion keeps building for up to a day and that lightly abrading the metal improves the electrical contact [3].

How adhesive-backed conductive parts are cut and supplied

Adhesive-backed parts ship either loose, each on its own piece of liner, or kiss-cut on a continuous liner for peel-and-place or pick-and-place assembly [6]. A kiss cut stops at the liner, which a die or a programmed knife can do; a waterjet cannot, because the stream cuts through the liner too. Conquest Seal cuts adhesive-backed conductive silicone sheet on its own pure-water waterjet, with the release liner on, so each part ships loose on its own piece of liner. A waterjet cannot kiss-cut, so parts wanted on a continuous liner are a separate line on the quote. The guide to cutting conductive silicone gaskets compares the processes, and adhesive-backed gasket material covers peel-and-stick sheet that does not need to conduct.

What to put on the drawing

• Adhesive: yes or no.
• Conductive or non-conductive, and the adhesive or tape the drawing names, by maker and number.
• Where it goes: full width, or a strip of a stated width and position, and on which face.
• How the parts ship: loose on their own liner, or kiss-cut on a sheet or a roll.
• The service temperature, so the adhesive's published limit can be read against it.
• Whether the joint is a connector or grounding contact that needs the lowest resistance.

Send the drawing through request a quote and a person replies within one business day. The EMI gasket overview lists what else a quote needs for each gasket form.

Chomerics is a trademark of Parker Intangibles LLC, a Parker Hannifin company; 3M is a trademark of 3M Company. No affiliation or endorsement is implied.

Sources

1. [1] Parker Chomerics, Conductive Elastomer Engineering Handbook, MS EN 111616, Edition II (2016): Pressure Sensitive Adhesive (PSA) Backing pp. 29 to 31 (typical PSA properties); sheet stock p. 74; https://www.parker.com/content/dam/Parker-com/Literature/Chomerics/Parker-Chomerics-Conductive-Elastomer-Engineering-Handbook.pdf; read 2026-09-24.
2. [2] Parker Chomerics, EMI Shielding Engineering Handbook, November 2000 edition: sheet stock and die-cut parts, adhesive backing; read 2026-09-24.
3. [3] 3M, XYZ-Axis Electrically Conductive Tape 9713, technical data, April 2009; https://multimedia.3m.com/mws/media/66127O/3m-xyz-axis-electrically-conductive-tape-9713.pdf; read 2026-09-24.
4. [4] 3M, XYZ-Axis Electrically Conductive Adhesive Transfer Tape 9719, technical data, December 2010; https://multimedia.3m.com/mws/media/225039O/3m-tm-electrically-conductive-adhesive-transfer-tape-9719.pdf; read 2026-09-24.
5. [5] 3M, Electrically Conductive Tapes and Films Selection Guide (2021); https://multimedia.3m.com/mws/media/1924428O/3m-electrically-conductive-tapes-films-selection-guide.pdf; read 2026-09-24.
6. [6] Specialty Silicone Products (a compounder), Die Cut EMI Gaskets and Materials; https://sspinc.com/emi-gaskets/die-cut-emi-gaskets/; read 2026-09-24.
7. [7] Specialty Silicone Products, EMI Gaskets: Conductive Silicone and Elastomer Gaskets; https://sspinc.com/emi-gaskets/; read 2026-09-24.