How to Choose the Best Rubber Compound for Specific Applications

A rubber compound is produced by adding specific chemicals to raw rubber material in order to improve and alter the characteristics of the rubber for desired use. Selecting the correct rubber compound is vitally important for any application. There are many types of rubber and GMT have a wealth of experience in selecting and manufacturing the right compound to suit customer requirements. Using our in-house computer controlled automated mixing systems, we can ensure the correct formulation is produced based on the many thousands that GMT have developed previously.

The following tables display some of the most frequently used rubber compounds and their characteristics such as heat resistance, as well as the best suited for resistance to light and chemicals. The tables can be used as a guide to help you select the preferred rubber compound for a particular application. For many applications, natural rubber is the preferred choice as natural rubber often provides the best dynamic properties overall. In addition, additives can be used to improve characteristics such as a resistance to ageing.
Synthetic rubbers can also be mixed with natural rubber to create hybrid compounds which can benefit from characteristics of each type of compound.

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Automotive Rubber Compound Application

For automotive applications, the presence of media such as oil and petrol calls for the natural rubber to be physically protected, often by a metal cap. The additional challenge in an automotive assembly is the design for high temperatures, as it is not always possible to shield the natural rubber from these temperatures, even after undertaking the usual techniques of cooling or remote placement. In these instances NBR, fluorinated rubber and silicone are preferred due to their resistance to heat, the latter also displays excellent resistance to low temperatures.

Marine Rubber Compound Application

For submerged marine applications, chloroprene or neoprene is often used due to its good resistance to salt water. Where there is a lower level of salt spray, natural rubber can sometimes be used, often with additional spray protection by a cover or sealed unit. For more information on the marine industry and using the correct components for protection against conditions at sea, check out our previous post.

How to Avoid Building Up Heat

Another important consideration in rubber selection is the build-up of heat due to high frequency dynamic loading. In some cases, the molecular friction can cause the rubber to heat up to the point that either the metal-to-rubber bond fails or the rubber itself does. Normally, this can be counteracted by choosing a rubber compound with lower dynamic stiffness, using a higher volume of rubber, or applying special low damping or high elastic compounds.

Why choose GMT Rubber?

GMT parts predominantly consist of rubber bonded to metal, so in addition to selecting the right rubber, the metal selection is very important. Whereas mild steel is well suited to most applications, the marine environment requires resistance to salt water. In these cases stainless steel is often preferred to avoid metal corrosion.

Under tightly controlled conditions and machine parameters unique to each production batch, the vulcanisation of the rubber compound is achieved. This process also produces a strong bond between rubber and metal where applicable, to be followed by a strictly adhered curing period. The curing period is crucial in achieving optimised performance and longevity of the rubber.

All batches of rubber produced by GMT are computer controlled and 100% tested prior to being accepted for production, this ensures traceability through to the finished product. This also successfully identifies the suitability of the rubber batch to meet the customer’s requirements.

GMT have over 50 years of experience in identifying and selecting the correct rubber compounds to meet the requirements of our customers, even in the harshest of applications and operating environments. If you require information and advice on what rubber compound is the right fit for your application, contact us and our technical sales team will be pleased to help.

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