Rubber is a material that possesses a great deal of flexibility. Think about it – there’s almost no industry today that doesn’t use rubber in one way or the other. And, the material also works in making a broad range of products.
Over the years, the flexibility of rubber has also managed to extend beyond its use. Today, there are so many types of rubber that you’d almost get lost trying to make a distinction. As more of these variations are being developed, many people are asking the major question – which is the best?
At the end of the day, this question is open-ended. But, one rubber variant that has really been making waves recently is HNBR rubber. We decided to look into it to explain why it is such a popular option at the moment.
What Is HNBR Rubber?
So, let’s get down to it – what is HNBR?
Well, HNBR represents “Hydrogenated Nitrile Butadiene Rubber.” It is a synthetic rubber variant, which means that you can’t get it from natural sources. Instead, the rubber is obtained via a process known as copolymerization.
To get HNBR, two monomers are combined – butadiene and acrylonitrile. The combination provides this material which has a distinguishing feature of being incredibly stable and strong.
For it to be created, HNBR works via the dehydrogenation of the butadiene segments available in nitrile rubber – or NBR, for short. The meaning of NBR itself is an oil-resistant synthetic rubber that is eventually processed to come up with HNBR. and as the chemical change increases the saturation of the material by altering some of the double bonds in the butadiene with single bonds, you get HNBR – a material with better properties than NBR across the board.
So, to recap, you have a hydrogenation process for NBR that changes its physical and chemical properties, thus creating HNBR. And, the resulting material itself has some interesting elements that form it. These include:
Acrylonitrile (ACN): A primary monomer, ACN allows HNBR to display several key characteristics – including and especially resistance to external materials.
Butadiene: Next, you have butadiene – another material that helps in the synthesis of HNBR. Generally, it makes the rubber more elastic and allows it to withstand a considerable amount of external force.
Hydrogenation: Combining these materials, hydrogenation helps to provide HNBR with the overall stability that it offers.
Key Characteristics Of HNBR Rubber
With a sufficient introduction to the material, let’s look into HNBR and what makes it really special. What are the factors that set it apart?
- External Effect Resistance: HNBR easily resists external factors like heat and oxidation. In fact, you’ll find that its ability to withstand heat and oxidation is more than that of nitrile rubber itself. The material doesn’t lose its performance when it comes in contact with higher temperatures, and this improves its functionality significantly.
- Chemical Resistance: You can count on this material to also keep any chemicals at bay. They have zero effect on it, and this makes the material perfect in situations where you need to protect internal base items from any chemicals.
- Flexibility In Cold: We already spoke about how HNBR doesn’t fold when it comes in contact with heat. Well, the exact same benefit can be felt when you place it in cold environments. So, it really doesn’t matter what environment you put it in – as long as you need it to maintain its properties, HNBR will stay.
- Strength: You can also count on the material to stay strong and withstand significant levels of abrasion. If you need long-term physical performance and durability, HNBR is perfect for you.
- Stretchability: Just as you get with the NBR material, HNBR is quite flexible. Stretch it, and it’ll come right back.
- Ability To Seal: Since it repels any external forces or materials, HNBR does well when it needs to act as a seal. To make things better, the material creates a seal across different temperatures and pressure ratings.
- Resistance To Weather: Natural elements like weathering and exposure to ultraviolet light have little to no effect on HNBR. so, if you need a rubber material for something that’s outdoors, you can count on it to be of significant help to you.
- Susceptibility To Compounding: Remember that you can still further compound HNBR with other additives to improve some of its physical and chemical properties. So, there are avenues for further development.
How HNBR Rubber Is Made
So, now that we’re familiar with the HNBR rubber material, let’s look into how it is made, and how NBR rubber becomes this product:
The Principle Of Polymerization
Central to the creation of HNBR is copolymerization- a process where you take two monomers and combine them. In this case, we have butadiene and acrylonitrile (ACN). So, how is the process done?
Preparing Your Mixture
Now that you have the monomers, you group them with different catalysts and additives and catalysts in a simple rubber mixing vessel. As polymerization occurs, you want to make sure that you have a proper view of things like the pressure and ambient temperature.
Polymerizing Using A Reactor
For this process to work, you need to take the mixture and put it in a reactor. In most cases, you have to control the pressure and temperature settings as you begin polymerization. This way, the monomers can be combined, and you can form the necessary polymer chains.
Adding Hydrogen To The Mix
Once the polymerization process is complete, you can go ahead to hydrogenate the NBR polymer. Essentially, you add hydrogen gas to what you have under high temperature and pressure.
The point here is for the hydrogen gas to react with the carbon double bonds available in the polymer. This reaction causes them to become single bonds, thus covering the polymer chain. Like that, the material gets better resistance to external elements like oils and heat
Filtering The Excess Hydrogen
In some cases, it might be necessary to remove any excess hydrogen from the mix. Once the desired effect of adding hydrogen has been achieved, there really isn’t a reason for you to leave any extras.
Leave The Mix In Air
Well, your HNBR is ready. It’s time to put in the finishing touches.
All you have to do is dry the HNBR to take out excessive moisture. From there, you can form it into pellets and bales and send it out to anyone looking to process it further.
What Is HNBR Rubber Used For?
It might be a relatively new form of rubber, but HNBR is starting to really get some steam. And like the many other rubber variants, we’re seeing it being used in different aspects. Some of these include:
Making Cars & Vehicle Components: In the automotive space, HNBR lends its ability to resist oil, heat, and other elements to the creation of gaskets, seals, and more. The goal here is to make sure that all components under a vehicle’s hood are properly sealed, and that there are no flare-ups.
Extracting & Processing Oil: Next, we have the product and its use in processing and taking out oil from the Earth’s surface. Here, HNBR lends several of its most prominent properties – including and especially material resistance – to ensure that several of these high-pressure applications can be processed correctly.
Enabling Aviation Resources: Makers of airplanes and other aerospace vehicles also use HNBR to make gaskets, seals, and more. In a way, this makes the application especially similar to automotive uses. With HNBR’s ability to withstand high-pressure fluids and abrasion, it is especially functional in this industry.
The Manufacturing Applications: We’ve seen instances where HNBR is used in different forms of manufacturing machinery and industrial tools. Many of these components have to work in really tough situations, and HNBR ensures that they can work accordingly.
Use In Healthcare Situations: There are a few grades of HNBR that are used in making or coating different medical devices. The material does well against sterilization and other chemicals, so it’s easy to see why it will be used. HNBR might not be so popular in the medical space, but this is worth mentioning anyway.
Popular Everyday Goods: We should also mention HNBR’s use in developing some of the most prominent consumer products available. From sporting equipment to protective materials and more, the material is quite versatile across the board.
Advantages of HNBR Rubber
Merely looking at the industries that make use of this material, you’d probably be tempted to want to ask about why it is so advantageous. Well, HBNR is currently one of the most popular rubber variants out there, and that is because of some of the following properties and benefits that it has:
Holding Back Any Heat
One of the biggest reasons why the material has become so popular is that it doesn’t let heat through. And, this is especially important because the standard NBR foam or rubber might not actually do so well with repelling heat.
So, HNBR picks up the slack and ensures that no heat is allowed to go into the material.
Keeping Chemicals At Bay
We should also point out the fact that HNBR does pretty well against the entry of chemicals. From fuel to solvents and fuel, the material can provide a proper protective coating against any of these elements and ensure that they don’t have any leakage to pass through.
You Get Long-Lasting Functionality
HNBR’s impressive mechanical properties mean that it can last for so long. What is it you’re looking for? Tensile strength? Abrasion resistance? Rest assured that HNBR’s got it!
Flexibility In Low Temperatures
Besides the fact that it holds its own when it encounters a considerable amount of heat, HNBR also does well in low temperatures. So, if you’re worried about the material maintaining its functionality in the cold, you really shouldn’t.
When it comes to HNBR, resistance is easily the name of the game. And, the material does well to resist not just heat; but several potentially intrusive materials as well. From oil to intrusive fluids, HNBR ensures that none of them is able to get space in.
It’s little wonder that the material works so well for vehicle components.
There’s no way to speak about NNBR that won’t include its ability to stretch and get back to its original form quickly enough. The material is an elastomer, so that shouldn’t be a surprise. However many times you want to stretch HNBR, you can rest assured that it’ll come right back to its original form.
Fit It To Your Taste
HNBR doesn’t necessarily have to work alone. You can compound it with different additives if you feel like the characteristics it exhibits aren’t enough. Once they work well with the material, everything else is easy from there!
Comparing HNBR Rubber & Other Rubber Types
So, we know everything there is to know about HNBR at the moment. But, you should also remember that this is just one of the many types of rubber available. From silicone rubber to polyurethane rubber and so much more, there’s just a whole lot to choose from, to be fair.
And, if you’re looking to weigh your options, here is a comparison of HNBR and some of the other rubber variants that tend to be used in its place:
HNBR vs Nitrile Rubber
We already pointed out the fact that HNBR usually comes from Nitrile Butadiene Rubber in the first place. So, which could be better for you and how do you know which one to use?
Comparing Their Properties
At the end of the day, one of your biggest points of focus will be to choose which rubber material best resists things like oils and chemicals. And, on this front, HNBR actually takes the win.
To be fair, NBR can withstand a whole lot of external materials. But, HNBR takes this to a different degree entirely.
Performance With A Temperature Range
Another area where many people tend to draw the line when it comes to rubber is how the material performs when presented with a broad range of temperatures. And as you’d imagine, HNBR does quite well in this regard too.
While NBR maintains its properties across a range of about 100-120°C (212-248°F), HNBR does even better, standing strong between 120°C and 150°C (248°F and 302°F).
Which Is More Expensive?
Considering that NBR is the material that leads to the synthesis of HNBR, you can imagine that it costs less. You’ll need to go through an entire set of processes to make HNBR, and that means that the material will be comparatively costlier.
That said, when you consider the benefits that you stand to gain from HNBR, you’ll discover that it is definitely worth the extra dollars.
The Overall Use
Both materials actually work in similar situations. From making gaskets to O-rings and seals, they’re pretty versatile. However, the fact that HNBR operates across a broader temperature range and provides even better features means that you will most likely get more functionality from it than NBR.
HNBR vs EPDM rubber
Last but not least, let’s look into another new but rising variant of rubber – Ethylene Propylene Diene Monomer (EPDM). Also a synthetic rubber, this variant was first discovered around the 1960s and has continued to become one of the most prominent forms of rubber available on the open market.
So, where and how does it compare with HNBR? Let’s take a look:
Protecting From Heat
A major stipulation for rubbers is heat resistance. And on that front, HNBR once again takes the win. While it holds its own for temperatures more than 150°C (302°F), EPDM actually has this point as the top of its peg.
At the end of the day, both variants offer an impressive level of heat resistance. But, one of them is much better – and that’s HNBR.
Amongst the many mechanical properties available with HNBR, durability is one area where it shines brightly. Compared to EPDM, it lasts longer and maintains its properties without having to bother about degradation.
Heat isn’t the only thing that HNBR is able to resist, as you very well know. The material also holds its own against chemicals and solvents, making it a viable option if you’re considering material strength overall.
That said, EPDM bests HNBR when you consider weather and UV resistance. It is a much better option for anyone looking to get a material that works in outdoor situations, and that shouldn’t be understated at all.
If you’re looking to save money, then you might want to buy EPDM instead. It is a more budget-friendly option than HNBR, and when you consider that they both almost do the same thing, you might not lose so much at the end of the day.
It might be one of the newest and most obscure forms of rubber, but there’s a general sense that HNBR could easily become the de facto market leader soon enough. And when you see its properties, you can kind of tell why.
For now, the potential for exploring HNBR is quite impressive. And, we at Legenday are excited about partnering with anyone who wants to make use of the material. Reach out to us today if you’re such a person.