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HSN/HNBR O-Rings
Technical Properties of Hydrogenated Nitrile Butadiene Rubber (HNBR) O-ring Material
Hydrogenated nitrile butadiene rubber (HNBR) O-rings, also known as high-saturation nitrile butadiene rubber (HSN) O-rings, are synthetic polymer seals made through a hydrogenation process that saturates the double bonds in the butadiene segments of nitrile butadiene rubber (NBR). This special process reduces the number of double bonds in the NBR molecular chain, making HNBR more heat-resistant, ozone-resistant, and chemically resistant than ordinary nitrile butadiene rubber, and also providing superior mechanical properties. HNBR O-rings are available in hardnesses of 70, 80, and 90.
Suitable media: petroleum-based oils/fuels, aliphatic hydrocarbons, vegetable oils, silicone oils/greases, ethylene glycol, water and steam (up to 300℉), dilute acids/dilute alkalis/dilute salt solutions. Media that cannot be contacted: chlorinated hydrocarbons, ketones, ethers, esters, strong acids.
Acrylonitrile content
Similar to nitrile butadiene rubber (NBR), hydrogenated nitrile butadiene rubber (HNBR) polymers also come in three grades with an acrylonitrile (ACN) content ranging from 17% to 49%.
Acrylonitrile content is correlated with material properties: lower ACN content imparts better low-temperature performance but relatively weaker resistance to fuels and polar lubricants; higher ACN content weakens low-temperature performance but significantly improves resistance to fuels and polar lubricants.
Standard HNBR typically has an acrylonitrile content of 36%.
Peroxide curing system
Hydrogenated nitrile butadiene rubber (HNBR) O-rings are generally vulcanized with peroxides. If you want them to be more flexible in dynamic systems, you can switch to sulfur vulcanization. However, sulfur vulcanization has a drawback – it reduces the material’s heat resistance and also worsens its compression set performance.
HNBR O-ring compound
| Compounds | Durometer | Color | Temp Range (F) | Description |
|---|---|---|---|---|
| H90-B701 | 90 | Green | -40 to +303 | Heat/Chemical resistance |
| H90-B103 | 90 | Black | -67 to +302 | Rapid gas decompression resistance, Low temperature resistance |
| H90-B102 | 90 | Black | -13 to +302 | Rapid gas decompression resistance |
| H90-B101 | 90 | Black | -40 to +302 | Heat/Chemical resistance |
| H80-B701 | 80 | Green | -40 to +303 | Heat/Chemical resistance |
| H80-B101 | 80 | Black | -40 to +302 | Heat/Chemical resistance |
| H70-B701 | 70 | Green | -40 to +303 | Heat/Chemical resistance |
| H70-B101 | 70 | Black | -40 to +302 | Heat/Chemical resistance |
Preferred Environmental Guidelines for Hydrogenated Nitrile Rubber O-rings
Performs Well In:
- Petroleum-based oils and fuels
- Aliphatic hydrocarbons
- Vegetable oils
- Silicone oils and greases
- Ethylene glycol
- Dilute acids, alkalis, and salt solutions at suitable temperatures
Water, steam (maximum temperature tolerance: 150℃/300℉)
Doesn't Perform Well In:
- Chlorinated hydrocarbons
- Ketones
- Diethyl ethers
- Esters
- Strong acids