As a supplier of NBR (Nitrile Butadiene Rubber) gaskets, I often encounter inquiries regarding the suitability of our products in various environments, one of the most common being vacuum environments. In this blog post, I will delve into the properties of NBR gaskets, explore their potential use in vacuum settings, and provide insights based on scientific understanding and practical experience.
Understanding NBR Gaskets
NBR is a synthetic rubber copolymer composed of acrylonitrile (ACN) and butadiene. This combination results in a material with excellent resistance to oil, fuel, and other hydrocarbons, making it a popular choice for sealing applications in automotive, industrial, and aerospace industries. The acrylonitrile content in NBR can vary, typically ranging from 18% to 50%, which affects the material's properties such as oil resistance, hardness, and low-temperature flexibility.
The key properties of NBR gaskets include:
- Oil and Fuel Resistance: NBR has outstanding resistance to mineral oils, vegetable oils, and fuels, which makes it suitable for applications where contact with these substances is expected.
- Good Mechanical Properties: It offers good tensile strength, tear resistance, and abrasion resistance, ensuring long-term durability in demanding environments.
- Moderate Temperature Resistance: NBR can withstand temperatures ranging from -40°C to 100°C (-40°F to 212°F), depending on the specific formulation.
- Chemical Resistance: In addition to oil and fuel resistance, NBR also exhibits resistance to many chemicals, including some acids and alkalis.
Vacuum Environments and Sealing Requirements
Vacuum environments are characterized by low pressures, which can range from near - atmospheric pressure to extremely high vacuums approaching 10^-12 torr. In such environments, the primary function of a gasket is to prevent the ingress of air or other gases into the vacuum chamber, maintaining the desired level of vacuum.
The sealing requirements in vacuum environments are more stringent compared to normal atmospheric conditions. Gaskets must have low outgassing rates, which refers to the release of gases from the material under vacuum. High outgassing can contaminate the vacuum chamber, affect the performance of sensitive equipment, and compromise the integrity of the vacuum. Additionally, gaskets need to provide a reliable seal over a wide range of temperatures and pressures, and they should be resistant to any chemicals or solvents that may be present in the vacuum system.
Can NBR Gaskets be Used in Vacuum Environments?
The answer to this question is both yes and no, depending on the specific requirements of the vacuum application.
Advantages of Using NBR Gaskets in Vacuum Environments
- Good Sealing Performance: NBR gaskets can provide an effective seal in moderate - vacuum applications. Their rubbery nature allows them to conform to the mating surfaces, filling any irregularities and preventing gas leakage.
- Cost - Effective: Compared to some high - performance elastomers used in vacuum applications, such as Viton or silicone rubber, NBR is relatively inexpensive. This makes it an attractive option for applications where cost is a significant factor.
- Availability: NBR gaskets are widely available in various sizes and shapes, making them easy to source for different vacuum system designs.
Limitations of Using NBR Gaskets in Vacuum Environments
- Outgassing: One of the main limitations of NBR gaskets in vacuum environments is their relatively high outgassing rate. The organic compounds in NBR can release gases under vacuum, which can contaminate the vacuum chamber. This makes NBR less suitable for high - vacuum applications where extremely low outgassing is required, such as in semiconductor manufacturing or high - energy physics experiments.
- Temperature and Pressure Range: While NBR has a moderate temperature and pressure resistance, it may not be suitable for extreme vacuum applications that involve very high or very low temperatures and pressures. For example, in cryogenic vacuum systems where temperatures can drop below - 100°C (-148°F), NBR may become brittle and lose its sealing properties.
Applications Where NBR Gaskets Can Be Used in Vacuum Environments
Despite their limitations, NBR gaskets can be used in certain vacuum applications where the requirements are not as stringent.
- Low - to - Moderate Vacuum Applications: NBR gaskets are commonly used in vacuum systems with pressures in the range of 10^-1 to 10^-3 torr. These applications include vacuum ovens, vacuum pumps, and some industrial vacuum processes where a moderate level of vacuum is sufficient.
- Non - Critical Applications: In applications where the presence of a small amount of outgassing is not a critical issue, such as in some laboratory vacuum setups or less sensitive industrial processes, NBR gaskets can be a cost - effective solution.
Alternatives to NBR Gaskets in High - Vacuum Applications
For high - vacuum applications where low outgassing and high performance are required, other elastomers or materials may be more suitable.
- Viton: Viton is a fluoropolymer elastomer that offers excellent chemical resistance, high - temperature resistance, and low outgassing rates. It is commonly used in high - vacuum applications, such as in the aerospace and semiconductor industries. Check out our Long - life Waterproof Wearproof Viton Epdm Oil Seal Ring for more information.
- Silicone Rubber: Silicone rubber has good flexibility over a wide temperature range, low outgassing, and excellent resistance to ozone and UV radiation. It is often used in vacuum applications where temperature stability and low contamination are important.
- PTFE (Polytetrafluoroethylene): PTFE is a synthetic fluoropolymer with extremely low friction, high chemical resistance, and very low outgassing. It is commonly used in high - vacuum applications as gaskets or seals, especially in applications where contact with aggressive chemicals is expected.
Our NBR Gasket Products for Vacuum Applications
As a supplier of NBR gaskets, we offer a wide range of products suitable for various vacuum applications. Our Long - life Waterproof Washer Shaft Oil Seal Ring is designed to provide a reliable seal in moderate - vacuum environments, with good oil resistance and mechanical properties. Additionally, our Long - life Pneumatic Cylinder Nbr Seal Ring Gasket is suitable for use in vacuum systems where pneumatic cylinders are involved, ensuring efficient operation and long - term durability.
Conclusion
In conclusion, NBR gaskets can be used in certain vacuum environments, particularly in low - to - moderate vacuum applications where the requirements for outgassing and temperature resistance are not extremely high. However, for high - vacuum applications where low outgassing and high performance are crucial, alternative materials such as Viton, silicone rubber, or PTFE may be more appropriate.
If you are considering using NBR gaskets in your vacuum application or need more information about our products, we encourage you to contact us for a detailed discussion. Our team of experts can help you select the right gasket material based on your specific requirements and provide you with the best solution for your vacuum sealing needs.
References
- "Handbook of Elastomers" by B. D. Croll and C. P. Parks
- "Vacuum Technology: A Practical Guide" by O. D. J. Soo and S. C. Tan
- "Rubber Technology" by Maurice Morton