Why You Should Choose a Silicone Gasket

Gaskets are an integral part of any application, especially in automotive engines where they play a crucial role in keeping the engine temperatures in check. This is why choosing a gasket material deserves special attention. Choose the wrong one, and you could see a significant drop in production.
Depending on what your application requires, silicone could be just the material you need.

Silicone Versatility

If you are considering silicone for your application, you will have a wide variety of choices in properties that will make it a perfect fit:

Silicone sheets and rolls come in a variety of thicknesses, from 0.10” thick to .500” thick.
Silicone can have a hardness anywhere from 10 Shore A to 80 Shore A.
Molding compounds can be pigmented to match the color chips or Pantone color designations.
Closed cell silicone sponge and foam come in sheets and rolls, from .032” thick to .500” thick. Its densities range from ultra soft to extra firm.
Silicone rubber has the broadest range of firmness and densities.
Fluorosilicone is resistant to fuel, oil, and chemicals.

Compression Set Resistance

Compression set, which occurs when a rubber cannot return to its original thickness after experiencing prolonged compressive stress, is an important factor to consider when choosing a gasket material. If compression set is one of your main concerns, silicone will be one of your best choices: two of the top-ranked compression-resistant materials are silicone and silicone sponge.

Flame Retardant

If silicone is compounded, its ability to resist flames is impressive. It can achieve UL94V0, UL94V1, and UL94HF1 flammability standards. For this reason, silicone is relied on for analytical instrumentation, telecommunications equipment, and controls found in Mass Transit systems. Even if silicone burns (which is only possible under extreme temperatures), its byproducts are non-toxic, and its residual ash can even provide electrical insulation.

FDA Regulations

Silicone can be compounded with FDA-approved ingredients to gain properties like high tear strength and flexing by using platinum-based catalysts. This makes silicone great for healthcare, instrumentation, food processing, and medical diagnostic equipment.

Electrical Conductivity

By blending silicone with nickel-graphite or silver-plated aluminum particles, silicone can be used as an electrically conductive gasket providing EMI shielding for use in electronic communication equipment. This form of silicone comes in a sheet or a custom-molded gasket.

Electrostatic Discharge (ESD)

In applications where ESD is a problem, silicone can be blended with a semi-conductive carbon to gain ESD properties.

Extreme Temperature Resistance

Unlike other organic elastomers like EPDM and neoprene, silicone rubber can retain its thickness even after exposure to a wide range of temperatures. This range goes as low as -60°C to as high as +250°C. In fact:

It can be used at 150°C continuously without experiencing any change in its properties.
Certain compounds can even withstand up to 200°C for 10,000 hours or more.
Certain forms of silicone can withstand 350°C for short periods.
Most forms of organic rubber become embrittled at -20° to -30°C.
Some kinds of silicone products can retain elasticity at -100°C and lower.

Silicone Sponge and Silicone Foam

Silicone sponge (also called closed cell silicone sponge) is made from a thin sheet of uncured silicone gum. Closed cell means that the cells are not interconnecting, preventing water from wicking through the sponge. It also has strong mechanical properties.
Silicone foam is an open cell, lightweight material. Higher density open cell variants are suitable for water sealing, while lower densities will allow moisture to pass through.

Other Properties

Due to its closed cell structure, silicone is great at water sealing with relatively low compressive forces. UL 50 and UL 50E are available.
Silicone is excellent at resisting UV and ozone because it has an inorganic backbone. This extends the performance of the gasket in the long-term.
Silicone sponge is much tougher than silicone foam.
All of silicone’s properties make it a great choice for outdoor environments with extreme conditions, such as the Arctic tundra and the desert.

No matter what gasket material you choose, make sure that you understand the major causes of gasket failure, and how to prevent them.

Consult the Industry Leader

If you are ready to make a purchase for your seal, consult the industry experts at Real Seal today. Real Seal has been an industry leader since the 1970s, and continues to innovate with its own chemist and technical staff. No matter what type of seal or mechanical component you are looking for, Real Seal will have the answer you need.