What is elastomer?
Elastomeric compounds are rubber seals produced using natural rubbers or manufactured by the chemicals industry.
Elastomeric sealing compounds consist of between 50-60% rubber; the remainder of the compound consists of fillers, accelerators, vulcanising agents, ageing retardants, and other additives.
These modifications added to the raw materials help provide the perfect solution to meet your application requirements and specifications.
This type of elastomer sealing compound and elastomers used in o rings help prevent leaks in liquid, gas, and air.
However, you must choose the right elastomer for your application to ensure your application’s correct chemical and thermal compatibility.
To achieve a suitable sealing material from elastomeric compounds, the compound will go through a vulcanisation process where the elastomer’s properties and elements change to a more suitable and hard-wearing, functional seal.
Those compounds that provide optimum performance will carry with them constant properties. We’ve all heard of the saying `if it isn’t broke, don’t fix it,` and the same can be said when you find the right compound recipe that sits perfectly with your application. Changing this successful recipe, even ever so slightly, can have damaging performance effects.
To avoid any fluctuations in material quality, the team at Specialist Sealing Products uses batch identification numbers. Each batch is identifiable and tested as we continually check its suitability for production. These batch numbers are listed on all o rings to easily trace back to stages of the manufacturing process.
Types of elastomers
Below is a brief look at just a handful of elastomers available to choose from; there are many more on the market, and your o ring supplier will be able to work through your requirements to find the right one for you.
Nitrile rubber, also known as Acryl-Nitrile Butadiene Rubber – this elastomer has high wear resistance and good mechanical properties. However, it is not resistant to ozone or weathering. It also offers heat resistance up to +100 degrees Celsius and provides chemical resistance for propane, butane, petroleum, and oil.
Polybutadiene rubber – typically used alongside others to improve wear resistance and cold flexibility. Primarily used for tyres, drive belts, conveyor belts, etc. This type of elastomer is not suitable as a sealing compound.
Butyl rubber has good electrical properties and a low permeability role. It is also chemical resistant and heat resistant up to 130 degrees Celsius. However, it is not compatible with fuels, mineral oil, grease, and chlorinated hydrocarbons.
Chlorobutyl rubber has good compression set properties and can be compressed with other rubbers.
Chloroprene rubber – offers good ageing, ozone, and chemical resistance. It can also operate well under a fluctuating temperature range and has a heat resistance of up to 100 degrees Celsius and cold flexibility of -40 degrees.
Chlorosulfonyl Polyethylene rubber – includes additional chlorine and sulphur groups supporting the vulcanizate resistance to flames and mineral oils. It has heat resistance up to 120 degrees and cold flexibility of -30.
Epichlorohydrin rubber – provides good resistance to high temperatures, ozone, and mineral oils and fuels.
Ethylene Acrylate Rubber – provides high resistance to ozone and oxygen attacks but is not as compatible with ACM compounds when it comes to mineral oils.
Ethylene propylene rubber (EPM, EPDM) – great for sealing, especially providing effective seals in brake systems and applications using hydraulic fluids. With heat resistance up to 150 degrees and cold flexibility down to -50.
Fluorocarbon rubber (Viton) – this is by far the most significant compound for sealing materials. Suitable for a wide range of applications, this elastomer provides excellent resistance to high temperatures, organic solvents and chemicals, fuels, synthetic hydraulic fluids, oxygen, mineral oils, and more. FPM compounds like this also have a higher resistance to acid, fuels, water, and steam.
Polyurethane rubber – provides excellent wear resistance, high tensile strength, and high elasticity.
Silicone rubber – has good insulating and physiologically neutral properties, good heat resistance of +250 degrees, and cold flexibility down to -60. However, they do offer poor wear and tear resistance and have low tensile strength.
Styrd Butadiene rubber (SBR) – typically found in tyre production, SBR seals are primarily used in seals for non-mineral oil-based brake fluid.
Ultimately, you need the o ring material you choose to be perfectly compatible with the application in which it is to be placed.
O ring suppliers Leeds
Ultimately you need to know the application inside and out. Where the sealing will be used, elements that it will be exposed to, and what it will be required to do precisely, i.e., how is it needed to perform? This information will help to feed into finding the right elastomer solution for you.
Specialist Sealing Products has many years of experience working with various businesses across a wide range of sectors that require the perfect seal or gasket for their application.
Our knowledge of material selection, hardness factors, compression elements, and more is second to none, and we manufacture gaskets and seals to suit individual requirements upon request.
To find out more, call us today on 01535 274 776