NBR vs Viton Seals

NBR vs Viton Seals: Which Material Is Right for Your Application?
 

[2026-04-27] | By Xiamen Jinshun Sealing Technology Co., Ltd. Annie Xu

So you're trying to pick the right rubber seal for your valve, pump, or assembly - and you've narrowed it down to NBR (nitrile) or Viton (FKM). Smart move. These two are among the most popular sealing materials on the planet, but they're not interchangeable.

Pick the wrong one, and you'll get leaks, early cracking, or even a safety risk. Pick the right one, and your equipment runs smoothly for years.

I've worked with sealing materials for over two decades (Xiamen Jinshun has been doing this since 2002). Let me walk you through the real differences - with numbers, not fluff - so you can make a confident choice. No boring textbook jargon. Just what works.

Viton is a brand name (from Chemours, ex‑DuPont) for fluorocarbon rubber. Think of it as the tough guy for extreme environments.

The secret? Fluorine atoms in its structure. That makes Viton highly resistant to high heat, harsh chemicals, fuels, and ozone. It doesn't soften or swell easily.

Real‑world uses:

• Aircraft fuel systems
• Automotive fuel injection seals
• Chemical processing equipment
• High‑temp vacuum applications

At our factory, we've made Viton O‑rings for clients who need to handle diesel, biodiesel, strong acids, and even silicone fluids. It just holds up.

NBR - also called Buna‑N - is a copolymer of acrylonitrile and butadiene. It's the workhorse of the sealing world. Why? Because it offers excellent oil resistance at a lower cost than Viton.

NBR loves petroleum oils, hydraulic fluids, and aliphatic hydrocarbons. It's also more flexible than Viton, especially in cold conditions.

Where you see NBR seals:

• Automotive fuel and oil systems
• Marine fuel lines
• Hydraulic equipment
• Lab cleaning devices
• Even disposable gloves (though that's a different grade)

If your application involves regular oil exposure and moderate temperatures, NBR is often the smarter choice.

Let's get into the details. Below is a clear table that shows how they differ in the areas that actually matter.

Note: PTFE seals can handle even higher temperatures (up to 180°C continuous, 260°C peak), but that's a different conversation.

Go with NBR if:

• Your operating temperature stays between -30°C and 100°C.
• You need a seal that stays flexible in cold climates (e.g., outdoor hydraulic equipment in winter).
• The media is petroleum oil, diesel, gasoline, or hydraulic fluid.
• Dynamic movement is involved - like a piston seal or rotating shaft - where flexibility matters.
• You want a cost‑effective solution for high‑volume production.

Avoid NBR if:

• Temperatures regularly exceed 100°C.
• Ozone, UV, or weathering is a concern (outdoor use without protection).
• You're dealing with brake fluids, ketones, or strong acids - NBR will swell or degrade.

✅ Real example: A marine equipment manufacturer we work with chose our custom NBR O‑rings for fuel line connectors. The seals see constant cold seawater splash and diesel fuel. NBR has lasted 5+ years without failure.

Viton is the right choice if:

• Continuous temperature is above 100°C (even up to 210°C).
• The media includes acids, esters, silicone fluids, or aromatic hydrocarbons.
• The seal is exposed to ozone, UV, or outdoor weather for years.
• Static sealing (e.g., flanges, caps) - rigidity isn't a problem.
• You need compliance with NSF, FDA, or UL for drinking water or food contact (yes, we supply FDA‑grade Viton).

Be careful with Viton if:

• Your application is dynamic and cold (below -20°C). Viton hardens and can snap.
• Low pressure + high flexibility is required.
• Your budget is tight - but sometimes the reliability is worth the extra cost.

✅ Real example: A valve manufacturer needed a seal for a hot steam application (180°C). NBR failed in two weeks. Our custom Viton O‑rings (with FDA approval) have been running for two years.

People often ask: "Which lasts longer?" It depends.

• For chemical and weather resistance: Viton wins. It won't crack from ozone or burn up from a hot engine.
• For tear resistance and dynamic use: NBR wins. It can stretch and flex without ripping. Viton is stiffer and more likely to snap if forced to bend repeatedly.

Think of it this way: Viton is like a ceramic knife - extremely hard and resistant, but brittle under impact. NBR is like a tough rubber boot - flexible and forgiving, but not for fires.

At Xiamen Jinshun, we don't guess. All raw materials meet RoHS, REACH, PAHS. And most of our seals - both NBR and Viton - are approved by:

• NSF (drinking water)
• FDA (food contact)
• LFGB (German food safety)
• ACS, KTW‑W270, WRAS (European water & gas)

We're ISO9001:2015 and ISO14001:2015 certified. Our seals are used in food & beverage, electronics, autos, and sanitary products. So when you ask for a custom O‑ring, you get a tested, traceable part.

1. Can I use a Viton O‑ring instead of an NBR one in the same groove?

Mostly yes, but check temperature and flexibility. At low temperatures (below -20°C) in dynamic applications, Viton may leak because it stiffens. Also, Viton is denser, so compression set values differ. Always test first.

2. Which is better for diesel fuel – NBR or Viton?

Both work, but NBR is the classic choice for diesel and is cheaper. Viton is better for biodiesel (especially high‑percentage blends) or if temperature exceeds 100°C.

3. Are your NBR and Viton O‑rings made to standard sizes or custom?

Both. We're a custom O‑rings manufacturer - we can make any size, any durometer (hardness), any color. We also stock popular AS568 and metric sizes.

4. How do I know if I need FDA‑approved material?

If your seal touches food, drinking water, or pharmaceuticals, you likely need FDA or NSF approval. Tell us your application, and we'll recommend the right grade.

5. Do you offer ODM for international brands?

Absolutely. We've been the long‑term strategic partner for well‑known brands worldwide. You provide the drawing or idea - we handle mold design, material selection, production, and quality control.

Contact now

Choosing between NBR and Viton doesn't have to be a headache. Tell us your:

• Operating temperature (min & max)
• Media (oil, fuel, acid, water, etc.)
• Dynamic or static?
• Any required certifications (NSF, FDA, etc.)

We'll send you a tailored recommendation - often with a sample for testing.

👉 Contact Xiamen Jinshun Sealing Technology Co., Ltd.
Visit our website or email our engineering team directly.
We're ready for your wholesale, distribution, or ODM partnership.

Since 2002 - sealing solutions you can trust.