The best materials for rubber gaskets

The purpose of a gasket is to protect machinery from adverse weather conditions. By keeping water, dust, dirt and debris out of machinery, they allow the products to deliver optimal performance, minimising risk of damage. There are two common materials used for gaskets: silicone and neoprene. In this article, PIF explores the merits of both materials.

Rubber gasket

It is important for gaskets to be flexible, durable and versatile and, as silicone and neoprene both exhibit these characteristics, it makes them the obvious choices. However, deciding which material to use should be a careful consideration. There are a number of factors to take into account when deciding to purchase a silicone or neoprene gasket and PIF has examined the benefits of both.

Silicone gasket properties

Silicone gaskets come in solid, foam and sponge varieties – making it an extremely versatile option. It is a resilient material that boasts high temperature stability and does not react with many substances, rendering it generally inert. Silicone is an excellent choice for gaskets because it forms a tight seal and repels water. Plus, its ability to withstand temperature extremes makes it superior to many other types of rubber.
Solid silicone can be used with metal closures and requires good closure force, while the closed cell structure of silicone sponge and foam make them suitable for environmental sealing applications where lower closure forces are relevant. Suitable for use in either high or low temperature environments, Silicone sponge’s firmness is measured in psi or density, with two to five psi or 250kg/m3 considered soft and 14 to 20 psi or 650kg/m3 considered firm. Silicone foam with a closed cell structure is therefore suited for an environmental enclosure.

Silicone has good compression set performance, its advantages include:

  • Flexible – It won’t freeze or crack at high or low temperatures.
  • Waterproof – It won’t break down because of exposure to water.
  • Shrink-proof – It won’t shrink over the course of its lifetime.
  • Very good weather resistance – It is not susceptible to ozone or UV attack.

Neoprene gasket properties

Synthetic rubber neoprene is the DuPont trade name for chloroprene, a versatile synthetic rubber. It displays good resilience and resistance to UV and ozone damage. This durable material can withstand temperature highs of up to 120°C, and lows of down to -40°C. Neoprene has good chemical stability, and good general resistance to oils and petroleum-based fuels.

The advantages of neoprene include:

  • Good thermal stability – It is flexible over a wide temperature range
  • Waterproof and corrosion resistant – It is resilient to environmental factors.
  • Good all round chemical resistance – not unduly affected by common fluids or weathering.
  • Good all-round physical properties.

Neoprene and silicone gaskets compared

Neoprene and silicone have similar characteristics and uses. However, they are subtly different in properties and characteristics. When deciding which gasket material to specify, it is important to weigh up their advantages and disadvantages when compared to the particular demands of your application. Neither material is better than the other overall per se, it entirely depends on your specific needs.

Silicone is the best choice for applications that will be subjected to extreme temperature ranges or weather exposure, while neoprene is better for applications that require oil-resistant and tear-resistant properties. In essence, you would be well advised to speak to a Martin’s Rubber expert for an honest assessment of which particular material will best suit your application.

To speak to a Martin’s Rubber expert about your gasket requirements, call 023 80226330 or email sales@martins-rubber.co.uk.