When it comes to seals, the elastomer material is crucial because it determines sealing performance, durability, and compatibility with the working environment. Compounds are chosen based on temperature, fluids, chemical agents, and mechanical conditions. The main rubber-based compounds are:
- EPDM (Ethylene-Propylene-Diene): It is one of the most commonly used rubbers for seals, especially in civil and industrial applications. It is highly valued for its excellent resistance to aging, ozone, weathering, and UV radiation. Chemically, it performs very well with water, steam, saline solutions, detergents, and coolants. Its weak point is its poor resistance to oils, greases, and hydrocarbons.
- NBR (Nitrile Rubber): This is one of the most widely used rubbers for sealing applications in contact with oils and fuels. It is mainly used in hydraulics, pneumatics, and the automotive industry. On the other hand, NBR is sensitive to weathering, ozone, UV light, and has a limited temperature range.
- CR (Neoprene): Neoprene offers a good compromise between EPDM and NBR. It provides fair resistance to both weathering and light oils and greases, which is why it is often used in marine, industrial, and railway applications.
- FKM (Viton): FKM is a high-performance rubber used when operating conditions are particularly demanding. It offers excellent resistance to oils, fuels, solvents, aggressive chemicals, and especially high temperatures. It is typical in chemical, petrochemical, and aerospace applications, but its high cost limits its use to situations where standard rubbers are insufficient.
- SILICONE: Silicone is known for its exceptional thermal stability, both at low and high temperatures. It is very flexible, non-toxic, and often used in the food and medical sectors. However, it has poor mechanical strength and is unsuitable for contact with oils and fuels, so it is chosen more for thermal or regulatory requirements than for heavy mechanical applications.
