Elastomer products & applications
The beneficial properties of elastomers have led them to be used in a vast range of applications, from hydraulic and pneumatic seals in industrial machinery through to precision pharmaceutical mouldings. Their applications can be divided into two broad categories, ‘Sealing’ and ‘Non-sealing’.
Sealing applications
Seals are precisely formed, moulded or machined shapes that seal fluids or gases by conforming to the sealing surfaces and supplying adequate sealing force to prevent passage of the sealed medium. Initial sealing interference with the surfaces increases as the system pressure grows, since the pressure is transmitted omnidirectionally in the seal.
This helps to ensure effective sealing performance.
The inherent elastic properties of elastomers make them a natural choice for sealing applications. They are designed in geometry and formulation to resist the pressure, motion and environment to which they are exposed in service. In some cases, where the elastomer material is not inherently strong enough to withstand the environment in which it is exposed, additional components can be bonded or included in the seal design to increase the elastomer’s performance envelope, such as engineering plastics or metallic components.
Seals are used in applications such as instrument stems, rods, shafts, flanges, cylinders and pump pistons. They are widely used in the food industry, including in bottle lifters, keg seals, manway joints, hopper seals, cones and pipe seals.
Seals are constructed using virtually all types of elastomers with a wide range of reinforcements, fillers, additives and cross-linking technology. The versatility of elastomer systems offers value in the ‘fine tuning’ of elastomer properties to specific service conditions. However, there may be complex trade-offs in properties of elastomers, such as high compression set resistance but poor dynamic performance or high heat resistance but low chemical resistance to specific fluids.
Non-sealing applications
Elastomers are also widely employed in non-sealing applications. Elastomeric belts, for example, are used in a great number of applications including drive systems and power transmission. They are usually composite products that rely upon reinforcing structures and specific construction techniques to perform in their intended applications. As in many reinforced rubber products, fabrics and other materials such as glass fibre are often used to bear much of the load.
Flexible hoses are also typically constructed of reinforced elastomers and may be multi-layered by design. They are most commonly used to transfer fluids from one point to another or to transmit energy, such as in hydraulic applications. They can also be used as a connector to help absorb surges and vibration or as a conduit to pass other hoses, pipes or wires.
Elastomers are also used in personal protection and diving products. These include face masks, nasal units, fixing straps, neck seals, ankle and wrist seals, regulator valves and mouthpieces.
Liquid silicone elastomers often find application in products that require high precision, such as electrical connectors, multi-pin connectors, infant products where smooth surfaces are desired such as bottle nipples, medical applications as well as kitchen goods such as baking pans and spatulas. Silicone rubber is frequently overmoulded onto other parts made of different plastics.
Another use is for expansion joints, which are flexible connectors typically consisting of a fabric-reinforced elastomer construction, often with metal reinforcements. Industrial gaiters and bellows are another significant application for the protection of moving components from the elements and other contamination.
Elastomers also have many uses in civil engineering, for example for mounting structures to reduce effect of external noise, vibration or seismic forces; accommodating thermal movement (bridge bearings, expansion joints, pipe couplings, etc); acting as a barrier to water (water stops, plant linings, tunnel gaskets) and a wide variety of others including roofing membranes, rubberised asphalt, rail pads, inflatable formers and concrete texturing.
The automotive sector is another large user of elastomers, with tyres being by far the largest application by volume. Another key use is in suspension systems, where the components can be designed with very specific dynamic properties. Other areas where elastomers make an appearance include exhaust mounts, anti-impact devices, weather strips, windscreen wipers, seat foam and interior trims.
