When to choose HNBR and Low Temperature HNBR(LT HNBR)?
HNBR(Hydrogenated Nitrile Butadiene Rubber) is a synthetic elastomer that is derived from Nitrile Butadiene Rubber (NBR) through a hydrogenation process.
This process selectively hydrogenates the carbon-carbon double bonds in the butadiene units of the NBR polymer chain, resulting in a material with significantly improved properties.
Overall, the performance characteristics of HNBR are based on NBR, with additional hydrogenation bringing reinforcement effects. Hydrogenation reduces the unstable C double bonds in NBR polymers, thus HNBR has better and more comprehensive mechanical properties, chemical resistance, heat resistance, etc. than NBR.
The temperature resistance range of HNBR is usually -25 ℃~+150 ℃, and special low temperature resistance HNBR can reach -40 ℃~+160 ℃.
HNBR VS NBR Material Property Comparison
Compared to NBR materials, HNBR has better high temperature resistance, fuel resistance, and dynamic fatigue resistance. Therefore, HNBR materials have a wider range of application scenarios, such as the petrochemical industry, fuel systems, and dynamic sealing products with higher speed requirements.Here is a comparison of the basic property parameters between HNBR and NBR materials.
| Property | HNBR | NBR |
| Low Temperature Resistance:TR10 | -25°C (Hydrogenation reduces double bonds) | -35°C |
| High Temperature Resistance | 160°C (short-term 180°C) | 120°C (short-term 150°C) |
| Oil Resistance | Volume swell (ASTM D471): 5-15% | Volume swell (ASTM D471): 10-30% |
| Chemical Resistance | Strong resistance to ozone, oxidation, acids, and fuel | Vulnerable to ozone, oxidation, strong acids,fuel |
| Tensile strength | 20MPa | 15MPa |
HNBR VS Viton®(FKM) Material Property Comparison
HNBR offers good tensile strength, better low-temperature flexibility, and cost-effectiveness for oil-resistant applications up to 150°C. While Viton®FKM can work in extreme heat (200°C+) and harsh chemical resistance due to its fluorine-rich structure.Here is a comparison of the basic property parameters between HNBR and Viton®FKM materials.
| Property | HNBR | Viton®(FKM) |
| Low Temperature Resistance:TR10 | -25°C | -18°C (Low-Temperature FKM can achieve better performance) |
| High Temperature Resistance | 160°C (short-term 180°C) | 200°C (short-term 250°C) |
| Oil and Fuel Resistance | Good(polar -CN groups resist swelling in non-polar oils). | Better than HNBR (fluorine’s low solubility in hydrocarbons) |
| Chemical Resistance | Moderate | Good (C-F bonds inert to most acids, bases, and solvents) |
| Tensile strength | 20MPa | 13MPa |
HNBR Low Temperature Performance
HNBR is produced by hydrogenating the carbon-carbon double bonds in NBR, which significantly improves its thermal and chemical resistance. However, this saturation reduces the flexibility of the polymer chain, leading to poorer low-temperature elasticity.
The absence of double bonds restricts molecular mobility at low temperatures, increasing the glass transition temperature (Tg) and making the material stiffer.
Low Temperature HNBR(LT HNBR)
For some applications, besides exceptional balance of oil resistance, mechanical strength, and durability, the low temperature performance of HNBR has to be improved.
The solution is to introduce a small amount of third monomers into the unhydrogenated NBR, which are large volume flexible functional groups that disrupt the regularity of the molecular chain, thereby improving its cold resistance.
Then we can get low temperature HNBR(called LT HNBR) with TR10=-40℃.The price of LT HNBR is also much higher than normal HNBR.So it could be used for some applications in harsh low-temperature environments, such as the need to withstand certain working pressures at low temperatures
Below are some applications where LT HNBR is preferred:
1. Automotive Industry
- Fuel System Seals in Cold Climates Area:
LT HNBR is used in fuel injector seals, fuel tank seals, and O-rings to ensure elasticity and sealing performance during cold starts or in winter conditions.
- Turbocharger Hoses:
Turbocharger systems may be exposed to low temperatures during cold starts. LT HNBR maintains flexibility at low temperatures while withstanding high temperatures and fuel exposure.
- Transmission and Engine Seals:
In cold regions, vehicle transmissions and engine seals must endure low-temperature shocks. LT HNBR provides reliable low-temperature elasticity and oil resistance.
2. Oil and Gas Industry
- Seals for Arctic or Deep-Sea Equipment:
LT HNBR is used in downhole tools, blowout preventers, and pipeline seals in extreme low-temperature environments like the Arctic or deep-sea operations.
- LNG (Liquefied Natural Gas) Equipment Seals:
LNG equipment operates in ultra-low temperatures (below -160°C) and ambient conditions. LT HNBR adapts to such temperature fluctuations while resisting natural gas and lubricants.
3. Industrial Machinery
- Hydraulic Seals for Cold Environments:
Construction, agricultural, and mining machinery operating in cold regions require LT HNBR to ensure elasticity and oil resistance in hydraulic systems.
- Rotary Shaft Seals:
Rotating equipment like pumps and compressors in low-temperature environments rely on LT HNBR for reliable sealing and wear resistance.
4. Food and Beverage Industry
- Seals for Refrigeration Equipment:
LT HNBR is used in cold storage, freezers, and refrigeration systems to ensure elasticity and sealing performance at low temperatures.
-Seals for Food Processing Equipment:
In low-temperature food processing environments, LT HNBR resists oils and low temperatures while meeting food-grade material requirements.
5. Renewable Energy Sector
- Seals for Hydrogen Fuel Cells:
Hydrogen fuel cell systems require seals that can withstand both low temperatures (hydrogen storage and delivery) and high temperatures (battery operation). LT HNBR meets these wide temperature range demands.
- Seals for Electric Vehicle Cooling Systems:
Electric vehicle battery cooling systems may be exposed to low temperatures. LT HNBR maintains elasticity and resists coolant exposure in such conditions.
6. Other Specialized Applications
- Seals for Low-Temperature Laboratory Equipment:
Cryogenic lab equipment, such as freeze dryers and ultra-low temperature freezers, requires LT HNBR for reliable sealing performance.
LT HNBR is a primarily choose for applications requiring sealing performance, and oil resistance at extreme low temperatures. Thanks to contact us for better material selection according to your applications.
