Although rubber is a natural material, most of the products we refer to as being made of ‘rubber’ are in fact made from some form of synthetic compound. There are two main types in use – silicone and EDPM – but what exactly are these and what are the differences between them?
Ethylene Propylene Diene Monomer – or EDPM for short – is often found in use in the automotive and building industries. Common applications might be waterproofing sheets, window and door seals or electrical gaskets.
EDPM is used in these applications because it has very good resistance to environmental factors such as ultraviolet light, ozone and the effects of weather. The one area where it may not be as good as the silicone alternative is temperature resistance. EDPM products can only handle temperatures of up to 130 degrees Celsius, and at heats of 100 degrees or more it is prone to shrinkage.
What we refer to as silicone rubber is actually a polymer of silicone, carbon, hydrogen and oxygen. It’s used by silicone hose manufacturers such as https://www.goodflexrubber.com/pages/silicone-hose-manufacture but has a wide range of applications across a number of different industries.
Silicone rubber can be found in automotive, aerospace, rail and food and beverage industries. Compared to EDPM, silicone rubber offers good resistance to environmental factors, but it also has high temperature resistance – up to 230 degrees Celsius – and some grades can cope with up to 270 degrees. As well as its temperature resistance, silicone rubber is also a ‘sterile elastomer’. This means that it can be used to conform to food industry standards in things like gaskets and seals on food machinery, tubing in dairies or tubes in beverage vending machines.
Silicone has the added advantage of offering a longer service life than EDPM, meaning that components made from it need replacing less often, leading to less downtime lost to maintenance work.
The success of any application often hinges on the choice of material. It’s therefore vital to consider carefully the needs of your project and which material will best. Often sealing failures happen because the wrong material has been employed. You therefore need to look at the specific qualities you want – whether it’s temperature resistance, chemical resistance or the ability to withstand high pressures – and make your choice accordingly.