The Benefits of and Best Uses for Nitrile Rubber Manufacturing
Diverse manufacturing capability is a Romar Engineering hallmark, and a core part of our capability across elastomers, silicone, precision moulding, medical device manufacturing and additive manufacturing is expansive materials expertise.
Materials selection is one of the first decisions we make when tailoring our manufacturing solutions, and it’s central to robust and effective manufacturing outcomes. Carlo Cartini, our Director of Technical Development, explains the initial steps:
“Having a broad range of understanding of the strengths of all of the different polymer (and other material) types, we’re able to pinpoint the functional requirement that your product has and be able to guide you in the direction of where you need to go with material selection.”
At Romar, we commonly work with nitrile rubber, and here we explain its benefits and common manufacturing applications.
About nitrile rubber
Nitrile rubber is called by various names including Buna-N and NBR rubber, and common trade names include Perbunan, Nipol, Krynac and Europrene. It is an elastomer, which is a natural or synthetic polymer with elastic properties. The elastomers group also includes natural rubbers, silicone and other synthetic rubbers (such as neoprene and Viton).
“The term elastomer describes a polymer made up of lots of repeating units to create a larger chain,” explains Carlo. “Polymers can be either thermoplastic or thermoset. Elastomers are a subset of polymers that can stretch by 50% or more of their original length and snap back to their original shape. Elastomeric properties are determined by the chemical structures that make up the chain.”
Nitrile rubber is produced from a copolymer of acrylonitrile and butadiene, and the specific polymer composition determines the physical and chemical properties. The more acrylonitrile there is within the polymer, for instance, the higher its resistance to oils, but the lower its flexibility.
Beneficial properties of nitrile rubber
Overall properties of nitrile rubber include excellent resistance to oils, fuels, alcohols, silicone greases and hydraulic fluids. Additionally, nitrile rubber can exhibit high tensile strength and good resistance to tears and abrasion. It is less expensive than fluoroelastomers (Viton etc. which are used for the most extreme sealing applications) but still eminently suitable for general oil sealing applications.
Nitrile rubber is compatible with petroleum-based lubricants and resistant to many chemicals, with the exception of strong acids, alkalis and polar materials.
Nitrile rubbers can have a working temperature range from −30°C to 110°C continuously, or intermittently up to 150°C.
Every material has its pros and cons for commercial manufacturing applications. In the case of nitrile rubber, while it has increased oil resistance and strength, it has less flexibility than some other elastomers and less resistance to flame, ozone, sunlight and extreme weather.
Best manufacturing uses of nitrile rubber
Given its resistance to certain oils, fuels and chemicals, nitrile rubber is commonly used in the auto, aeronautical and mining industries.
“This is a material that is extremely suitable for use in hot oils, so it is resistant to engine oils and it is the backbone of a lot of the sealing applications in our engines for our motor vehicles,” says Carlo.
Other conventional applications include oil seals, fuel hoses, gaskets, O-rings, automotive transmission belts, V belts, synthetic leather, rollers and disposable non-latex gloves.
Materials selection for nitrile rubber manufacturing
Romar tailors every manufacturing solution for aerospace, mining, defence and other sectors, based on multiple factors including project aim, environment, budget and production run. Central to every manufacturing solution is bespoke material selection.
“For example, there is a material out there called EPDM,” states Carlo. “This material is a very good general-purpose rubber that is fantastic for open air applications; however, this material can actually be made in two very different ways.
With the general-purpose way, you can put it in a certain type of environment and it will fail dramatically, whereas if you prepare it in a different way, it doesn’t fail in that environment at all. Once we know what environment a customer wants to put a material in, we can recommend we go with a certain type, and move forward that way.”
Comprehensive Romar capability
Every material has its benefits that will make it our preferred choice for the required industrial, medical or advanced manufacturing solution. With extensive team expertise, we have the capability to design and refine the best manufacturing solution for every project and every industry.
“As a materials person, working with the polymers, the thermoplastic polymers and the thermoset polymers, is my strength,” says Carlo. “However, within Romar, on the engineering product side and in our manufacturing side, there is a great deal of experience in many other areas such as the use of the correct steels and the methods of treating those steels to get the right result in what we need to do.
So, whether it’s the metals to make a mould or fabricate a device, whether it’s moulding or materials, we have experience across the board to meet those needs.”