NBR 70 vs. Silicone

Attribute	NBR 70	Silicone
Material Type	Nitrile Rubber	Silicone Rubber
Temperature Range	-40°C to 120°C	-60°C to 230°C
Hardness	70 Shore A	40-80 Shore A
Chemical Resistance	Good resistance to oils and fuels	Good resistance to chemicals and solvents
Elasticity	High elasticity	High elasticity

Introduction

When it comes to choosing the right material for seals, gaskets, and O-rings, two popular options are NBR 70 and Silicone. Both materials have their own unique attributes that make them suitable for different applications. In this article, we will compare the characteristics of NBR 70 and Silicone to help you make an informed decision.

Chemical Composition

NBR 70, also known as Nitrile rubber, is a synthetic rubber copolymer of acrylonitrile and butadiene. It is known for its excellent resistance to oil, fuel, and other petroleum-based fluids. On the other hand, Silicone is a synthetic polymer made up of silicon, oxygen, carbon, and hydrogen atoms. It has a wide temperature range and is resistant to ozone, UV light, and extreme weather conditions.

Temperature Resistance

One of the key differences between NBR 70 and Silicone is their temperature resistance. NBR 70 has a temperature range of -40°C to 120°C, making it suitable for applications where moderate heat is involved. Silicone, on the other hand, can withstand temperatures ranging from -60°C to 230°C, making it ideal for high-temperature applications.

Chemical Resistance

When it comes to chemical resistance, NBR 70 is known for its excellent resistance to oil, fuel, and other petroleum-based fluids. It is also resistant to water, hydraulic fluids, and alcohols. Silicone, on the other hand, has good resistance to ozone, UV light, and extreme weather conditions. It is also resistant to water, steam, and some chemicals.

Compression Set

Compression set refers to the ability of a material to return to its original shape after being compressed. NBR 70 has a lower compression set compared to Silicone, making it suitable for applications where sealing under pressure is required. Silicone, on the other hand, has a higher compression set, which may affect its sealing performance over time.

Flexibility

When it comes to flexibility, Silicone is known for its superior flexibility compared to NBR 70. This makes Silicone ideal for applications where flexibility is crucial, such as in medical devices and food-grade seals. NBR 70, on the other hand, is less flexible but offers better resistance to oil and fuel.

Abrasion Resistance

Abrasion resistance is an important factor to consider when choosing a material for seals and gaskets. NBR 70 has good abrasion resistance, making it suitable for applications where wear and tear are common. Silicone, on the other hand, has lower abrasion resistance compared to NBR 70, which may affect its durability in high-wear applications.

Cost

Cost is another factor to consider when choosing between NBR 70 and Silicone. NBR 70 is generally more cost-effective compared to Silicone, making it a popular choice for budget-conscious applications. Silicone, on the other hand, is more expensive but offers superior temperature resistance and flexibility.

Conclusion

In conclusion, both NBR 70 and Silicone have their own unique attributes that make them suitable for different applications. NBR 70 is known for its excellent resistance to oil and fuel, while Silicone offers superior temperature resistance and flexibility. When choosing between the two materials, it is important to consider factors such as temperature resistance, chemical resistance, compression set, flexibility, abrasion resistance, and cost to determine which material is best suited for your specific application.