Extruded conductive elastomer or rubber
gaskets are available in variety of cross section, they can be both solid
and hollow strips. Gasket profiles are now a days tailored according to
application methods, ultra-low closure force or to suit large deflection
ranges.
Gaskets are produced from extruded rubber and is used for prevention of
leakage of fluids or gases, under the impact of extreme temperature or
pressure. Extruded gaskets are today are used in a variety of applications.
The extruded gaskets gives the users a variety of choice regarding shapes
and design. Some of the types that are available these days include spiral
wound, sheet or die-cut, gasket strip, sanitary gasket, spiral wound, window
gasket etc. Sanitary gaskets have been successfully applied in pipeline
systems in the critical industries of food, pharmaceutical and bio-tech
industries. Some of the typical gaskets as used in industrial applications
are shown below.

These days gaskets are co extruded for combining dual purpose along with
simplicity. These Co-extruded gaskets provide optimum EMI shielding and
excellent protection against corrosion in a single yet cost-effective
design. The outer gasket that is non-conductive plays the role of an extra
environmental seal. This is to ward off the moisture from conductive
gasket/flange interface. A specific advantage of the Co extruded profiles is
cost effectiveness. Co-extruded gaskets allows the use of existing flange
designs. They provide for attachment of gasket through a less expensive
nonconductive elastomer.
Materials for Extruded Gaskets
Some of the materials that are typically used for extruded gaskets are
discussed here. First is TPE or Thermoplastic Elastomers / TPV
(Thermoplastic Vulcanizates).
- Thermoplastic Elastomers / TPV (Thermoplastic Vulcanizates)
These are materials that have been created to match the best properties
of rubber along with the flexibility and ability for easy processing as
in thermoplastics. Perhaps that is the reason why they are used for
gasket applications in place of EPDM and other rubber based products.
Some of the properties that gives them an edge over others include:
- Close Dimensional Tolerance
- Ability to be Co-extruded with different colors and materials
- Physically and Chemically stable
- Silicone Rubber
Silicone rubber is an excellent source for gasket materials. Silicone
extruded door gasket is quite popular in a number of industries.
Silicone gaskets offers the advantage of excellent resistance to a wide
temperature range from -80° C to +250°C. Silicone sponge is
made int extruded gasket profiles that are soft and easy to compress.
Making them most appropriate for enclosure and door sealing.
Application of Extruded Gaskets
The extruded gaskets are used in a number of popular applications, some of
the major ones are highlighted here for a quick reference.
- Refrigeration
A very good application of the extruded gaskets lies in its application
as door gaskets in the refrigeration industry. Other similar
applications included freezer door gaskets as well as cooler door
gaskets.

- Plumbing operations
Co-extruded gaskets are used for pipes made with PVC, Polyethylene and
concrete. The following image shows a Co-extruded gasket system that is
utilizing a dual durometer design. This not only gives a superior
sealing but also comes at a lower cost.
- Window Profiles
Coming to the housing sector co extruded/extruded gaskets are used in
window profiles.
- Other Industries
Other industries served include the critical communications industry
where it is used in the commercial as well as military communications
equipment. Extruded Rubber Gasket's use in Antenna system of a passenger
car is described in the image below:
Case Study on the effectiveness of Co extruded gaskets
- The Challenge
The challenge was for a pole-mounted, aluminum telecom enclosure. There
was need to control EMI and to keep out the elements. The said enclosure
required a conductive gasket that shows a capability of at the least 80
dB shielding effectiveness in high-low megahertz range. Along with that
there was need for a separate environmental seal for protection against
rain and moisture.
- Common Approach Undertaken
At first a hollow silicone strip which is non-conductive and filled
with a pure-silver silicone was extruded on to its surface. What
happened was that on getting contact with the aluminum housing, along
with exposure to coastal salt fog and driving rain, there was severe
occurrence of the corrosion of housing flanges.
- Effective Approach for Remedy
To rise up to the challenges of shielding and environmental
requirements, a co-extruded EMI gasket was used. A conductive elastomer
was extruded in parallel with an elastomer that was non-conductive. The
conductive side of the gasket is nickel-plated-graphite and filled with
silicone. The filler particles have the capability to bite through the
thin surface oxides as well as the chemical treatments on aluminum
housings. Long term integrity is provided by the vulcanized seam between
the elastomers. The conductive side of the Co extruded gasket is placed
inboard, while the non-conductive silicone is positioned outboard.
The cross section's non-conductive side is specifically designed for an
additional sealing tab that fills the existing sump area in the seam for
collection of rain and moisture. The efficacy of the Co extruded gasket
lies in the following:
- Use of existing flange design
- Eliminating the expenditure needed for separate shielding and
weather sealing gaskets
- Avoiding the need for conversion to a double-groove design.