The main elastomers from RADO at a glance
Fluoro rubber is characterised by excellent resistance to ozone, weathering, high temperatures, mineral oils, synthetic hydraulic fluids, fuels and many other media. This material is predominantly used in the form of hoses, cable insulation, seals, rubber coatings, roofing membranes and cladding. Fluoro elastomers are mainly used in the automotive industry, replacing materials which can no longer meet the tougher requirements in terms of chemical and thermal stability.
FVMQ has similar physical and mechanical properties to silicone rubber, but is also resistant to mineral oils and fuels. These elastomers are suitable for high temperatures, but also cope very well with cold. Preferred areas of application include the aerospace industry and natural gas production equipment. FVMQ is used in the automotive industry in the form of seals, O-rings and diaphragms for fuel systems at temperatures up to 170°C.
In addition to good high- and low-temperature properties, silicone rubber also offers good weathering and chemical resistance and good physiological characteristics. Its mechanical properties are more modest. Silicone is not resistant to mineral oils. Silicone elastomers are a popular material for moulded parts, flat seals and O-rings in medical technology and in the food industry, but they are also used for insulating electrical cables.
Pigment masterbatches are polymer-based additives which can be used to colour silicone mixes, fluorosilicone mixes and fluorocarbon compounds. These colouring elastomers do not form dust like powders or drip like liquids, so they are easier to process. If required, these special pellets can be treated with UV stabilisers, flame retardants, lubricants and many other additives. Standard RAL colours ensure consistency of colour in the final product and are also cost-effective.
HNBR elastomers offer excellent mechanical properties and much higher thermal stability than NBR. They are also resistant to mineral oils, vegetable and animal oils and fats and to hydraulic fluids. Among other things, hydrogenated nitrile-butadiene rubber is used as a sealing material for O-rings and lip seals in the temperature range up to around 150°C and in refrigeration plants in which the refrigerant R134A is used, for example.
AEM is resistant to heat, oil and ozone. It offers good resistance to lubricating oils and greases, even those containing aggressive additives. Typical applications for these elastomers include all types of static seals that come into contact with oil, as in oil pumps, transmissions and valve covers, for example. Ethylene acrylic rubbers ensure a long service life for parts in air management systems and in the powertrain of motor vehicles, and they offer long-term resistance to various chemicals across a broad temperature range.
Acrylic rubber offers good resistance to high temperatures, oxygen and ozone and good swelling resistance in mineral oils. Disadvantages include its poor hydrolysis resistance and high water absorption. The main area of application for these elastomers is the automotive industry, where they are used in particular for seals, O-rings, diaphragms and oil hoses for elevated temperatures. ACM is also used to make roller coverings.
Epichlorohydrin rubber combines the good properties of nitrile rubber in terms of mineral oil resistance and low compression set with good ozone and weathering resistance. However, ECO elastomers need relatively long cure times and the vulcanisates often have to be annealed too. Epichlorohydrin rubber is primarily used for seals, hoses and diaphragms in situations where there is also a need for good mineral oil resistance and resistance to ozone and ambient conditions.
NBR has good mechanical properties, good low-temperature characteristics and higher abrasion resistance and lower compression set than most other elastomers. Resistant to mineral oils, hydraulic fluids and fuels, it is used in fuel lines, hydraulic hoses and seals for fuel tanks. It is also made into various technical products, rollers, sheets and mats.
Chloroprene rubber is ideal for applications requiring high weathering, ozone, ageing and salt water resistance. Appropriate protective agents are added to the rubber compound to obtain these properties. CR is mainly used as a material for O-rings and seals in applications where refrigerants are used. Because of their good flame retardancy, these elastomers can also be used in areas where there is a risk of fire.
EPDM is resistant to oxygen and dilute acids and has better than average chemical resistance, very good ageing resistance and high rubber elasticity. This rubber is also resistant to mineral oil products. The elastomers are preferably used in conjunction with glycol-based brake fluid, hot water and superheated steam. Other areas of application include the automotive industry, the food sector and pneumatics.
