Buna

The development of Buna dates back to the early 20th century, when demand for synthetic alternatives to natural rubber was growing. The name “Buna” is derived from the starting materials: butadiene (Bu) and sodium (Na, from the German “Natrium”), which was used as a catalyst in the polymerisation. The synthetic rubbers were first developed by the German company IG Farben to reduce dependence on imported natural rubber.

Important Buna types

• Buna-S (SBR): styrene-butadiene rubber, widely used in tyre manufacturing because of its excellent abrasion resistance.

• Buna-N (NBR): nitrile rubber, known for its resistance to oils, fuels and chemicals. It is used in the automotive and aerospace industries.

There are various types of Buna rubber, each with specific properties and applications. The two most common types are Buna-S (SBR) and Buna-N (NBR), both of which are produced by copolymerising butadiene with different monomers.

Styrene-butadiene rubber (Buna-S, SBR)

Buna-S, also known as SBR (styrene-butadiene rubber), is one of the most widely used synthetic rubbers. It is produced by copolymerising butadiene with styrene and is characterised by good abrasion resistance and excellent ageing resistance.

• Properties: high abrasion resistance, good mechanical strength, moderate heat resistance, not resistant to oil and fuels.

• Applications: mainly in tyre manufacturing and in the production of conveyor belts, hoses, seals, moulded articles and rubber profiles.

Nitrile rubber (Buna-N, NBR)

Buna-N, also known as NBR (nitrile butadiene rubber), is produced by copolymerising butadiene with acrylonitrile. It is particularly known for its excellent resistance to oil and fuel and for its chemical resistance.

• Properties: very resistant to oils, fuels, greases and many chemicals, good mechanical properties, good heat resistance, moderate ozone resistance.

• Applications: widely used in the automotive and aerospace industries, particularly in seals, hoses, moulded articles, O-rings and fuel lines.

Buna rubbers offer numerous advantages over natural rubbers and other synthetic elastomers, which makes them particularly valuable in many industrial applications:

• High resistance: Buna-N in particular is known for its resistance to oils, fuels and chemicals, which makes it ideal for technical applications.

• Versatility: both Buna-S and Buna-N offer a wide range of mechanical and physical properties that can be optimised for a variety of applications.

• Availability and cost efficiency: because it is easy to produce and versatile, Buna is a cost-effective material for mass production, particularly in the tyre industry.

Buna rubbers are used in a wide range of applications, particularly in industries that require high resistance to mechanical stress and chemical influences.

Tyre industry

Most of the Buna-S (SBR) produced is used in tyre manufacturing. Tyre compounds containing SBR offer excellent abrasion resistance and ageing resistance, which improves the service life and safety of tyres.

Automotive and aerospace industries

In the automotive industry, Buna-N (NBR) is often used for seals, moulded articles, hoses and fuel lines. Its high resistance to oils and fuels makes NBR the preferred choice for these applications. In aerospace, NBR is used in applications that call for high performance and resistance to extreme temperatures and chemicals.

Industrial applications

Buna rubbers are also used in conveyor belts, hoses, seals, moulded articles and other industrial components that are subject to mechanical stress and require a long service life.

1. What is the difference between Buna-S and Buna-N?

The main difference lies in their chemical resistance: Buna-N (NBR) is particularly resistant to oils, fuels and chemicals, while Buna-S (SBR) is known mainly for its abrasion resistance and its use in tyres.

2. What advantages does Buna rubber offer over natural rubber?

Buna rubbers offer higher resistance to chemical influences and better adaptability to different industrial requirements. They are also more cost-effective and available in large quantities.

3. In which industrial applications is Buna-N preferred?

Buna-N is preferred in the automotive, aerospace and chemical industries, particularly for seals, hoses and fuel lines that require high resistance to oils and chemicals.

Buna rubbers play an essential role in modern industry, particularly in tyre and automotive production. They offer an excellent combination of resistance, versatility and cost efficiency, which makes them the preferred choice for a wide range of applications. Their ability to withstand mechanical stress and chemical influences makes them indispensable for many technical and industrial applications.