Nitrile Rubber (NBR)

At Kea-Flex, we regularly use nitrile rubber (NBR) due to its excellent resistance to oils, fuels, and many chemicals. This makes it a highly versatile material, ideal for a wide range of industries and applications.

One of the most common uses is in seals and gaskets, including O-rings and hydraulic seals. These components are widely used in engines, fuel systems, and hydraulic equipment, where they provide reliable sealing in demanding conditions.

Another common use of nitrile rubber is in fuel hoses and oil-resistant tubing, often for automotive and industrial clients. Nitrile’s durability in oily environments makes it well-suited to these applications.

Other typical uses include protective gloves—especially in chemically harsh settings—as well as moulded parts like grommets, diaphragms, bushings, and rollers, all valued for their strength, flexibility, and resistance to degradation. These components are produced using a variety of rubber moulding techniques, such as transfer, compression, and injection moulding, depending on the application and design requirements.

Yes, nitrile rubber (NBR) can be overmoulded with other materials, and at Kea-Flex, we have the expertise to support projects where overmoulding may be required. Overmoulding involves bonding nitrile rubber to a second material such as metal, plastic, or another elastomer to form a single, integrated component with enhanced functionality.

One common example is rubber to metal bonding, often used in parts that demand both strength and flexibility, such as seals, vibration dampers, or mounting components. Achieving a strong and durable bond depends on factors like surface preparation, adhesive systems, and precise moulding conditions.

Overmoulding nitrile onto other materials requires careful consideration of compatibility, bonding techniques, and application requirements. While not always necessary, it can be a valuable solution where performance or assembly advantages are needed.

At Kea-Flex, we carefully control the moulding process to ensure strong adhesion and consistent quality in overmoulded parts. We can advise on the best material combinations for your application, whether you need oil and fuel resistance, flexibility, or mechanical strength.

At Kea-Flex, we work with a range of elastomers, each chosen for its specific properties and suitability for different applications. Nitrile rubber (NBR) is among the most widely used due to its excellent resistance to oils, fuels, and greases. It also provides good abrasion resistance and mechanical strength, making it ideal for seals, gaskets, and hoses in automotive, industrial, and oil and gas settings. However, it has limited resistance to weathering, ozone, and UV, making it less suitable for prolonged outdoor use.

In contrast, EPDM rubber performs extremely well in outdoor environments. Its strong resistance to UV, ozone, and water makes it a common choice for building and automotive seals. That said, EPDM lacks the oil and fuel resistance that nitrile offers.

Neoprene rubber offers a balanced performance, with moderate resistance to oils and good durability outdoors. It’s often used for protective covers, external seals, and wetsuits. While more weather-resistant than nitrile, it doesn’t match its performance against oils and fuels.

Natural rubber is known for its excellent elasticity and mechanical strength, making it suitable for vibration mounts and shock absorbers. However, its poor resistance to oils, fuels, and environmental exposure limits its use in harsher conditions.

Silicone rubber excels in extreme temperatures, staying flexible from around -60°C to +200°C. It’s also highly resistant to UV, ozone, and weathering, making it ideal for medical, food-grade, and high-temperature applications. Its main drawbacks are lower oil resistance and reduced abrasion strength compared to nitrile.

Nitrile rubber (NBR) is a widely used elastomer thanks to its strong performance in demanding environments, particularly where oil and fuel resistance is essential. At Kea-Flex, it’s one of our most commonly moulded materials due to its reliability across a wide range of industrial and automotive applications.

Advantages – One of the key benefits of nitrile rubber is its excellent resistance to oils, fuels, greases, and many chemicals, making it ideal for seals, gaskets, hoses, and other components exposed to harsh fluids. It also offers good abrasion resistance and mechanical strength, which contributes to a long service life in dynamic applications.

Nitrile rubber has a relatively wide temperature range (typically around -30°C to +120°C), and it maintains flexibility and performance within that range. It also exhibits low gas permeability, which is useful in sealing applications where air or fluid leakage must be minimised.

Disadvantages – Despite its strengths, nitrile rubber does have some limitations. It offers poor resistance to ozone, UV, and weathering, which means it is not well suited to prolonged outdoor exposure unless specially formulated or protected. It also has limited flexibility at low temperatures, particularly below -30°C, where it can become brittle.

Additionally, nitrile is not suitable for use with strong acids, ketones, or certain polar solvents, which can cause it to degrade over time.

Yes, when moulding nitrile rubber (NBR), there are several important design factors to consider to ensure high-quality, consistent parts.

Nitrile rubber has a moderate to high shrinkage rate (typically around 1.4–2.0%), so moulds must be designed with appropriate allowances to achieve accurate final dimensions. It’s also important to position the parting line carefully, especially if the component includes sealing surfaces, to minimise flash and simplify deflashing.

Venting is another key consideration. Trapped air during moulding can lead to voids or surface imperfections, so small vents (usually around 0.01–0.03 mm deep) should be incorporated to allow gases to escape.

Adding draft angles (usually 1–3°) on vertical walls helps with demoulding, particularly for compression and transfer moulded parts. A smooth mould surface finish is also beneficial, as it improves part release and the surface quality of the final product.

In processes like rubber-to-metal bonding, proper mould alignment and surface preparation of the insert are essential to achieve a reliable bond between the rubber and substrate.

At Kea-Flex, we ensure every mould is expertly designed to suit the specific characteristics of nitrile rubber. Our team carefully considers factors such as shrinkage, venting, draft angles, and surface finish to produce accurate, consistent parts with a high-quality finish. We apply our technical expertise to deliver durable, high-performance products tailored to your exact requirements.