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If you have ever worked in the automotive, aerospace, or industrial sectors, you might have come across nitrile rubber sheets. These versatile sheets, also known as acrylonitrile butadiene rubber or Buna-N, are specially designed to resist oils, fuels, and chemicals while maintaining strong mechanical properties. Their unique combination of flexibility, durability, and temperature stability makes them a preferred choice for seals, gaskets, hoses, and other industrial components. In this article, we will explore what exactly a nitrile rubber sheet is, its composition, features, and applications.
A nitrile rubber sheet, also called NBR, is a versatile synthetic rubber widely used across industries. It is made from acrylonitrile (ACN) and butadiene, which combine to form a copolymer that delivers a unique set of properties. People also refer to it as Buna-N, acrylonitrile butadiene rubber, or NBR latex, depending on the region and manufacturer.
What makes NBR sheets special is their ability to resist oils, fuels, and many chemicals, which most natural rubbers cannot withstand. They are also highly durable, maintain flexibility under stress, and tolerate a wide range of temperatures. Because of these properties, NBR sheets are often preferred for applications where chemical exposure, mechanical stress, or oil resistance is critical.
NBR sheets are primarily made from two components that work together to provide both strength and resistance:
| Component | Role | Key Benefit |
|---|---|---|
| Acrylonitrile (ACN) | Imparts resistance to oils, fuels, and many chemical agents | Protects the sheet from swelling or breakdown |
| Butadiene | Provides flexibility, high tensile strength, tear resistance, and abrasion resistance | Ensures durability under mechanical stress |
The balance between ACN and butadiene is crucial. A higher ACN content increases chemical and oil resistance but reduces flexibility, especially at low temperatures. Conversely, a lower ACN content improves flexibility and elasticity but slightly compromises solvent resistance.
Some key points to remember about NBR composition:
ACN is the “chemical shield” for the rubber.
Butadiene gives it the ability to stretch, recover, and withstand tearing.
The ratio of these two components determines how the rubber behaves in extreme conditions.
In simple terms, NBR combines chemical toughness and mechanical strength in a way that few other rubbers can.
Nitrile rubber was first developed in 1931 by chemical giants BASF and Bayer, and its first commercial production started in Germany in 1935. Its development marked a major innovation in industrial rubber technology because it could handle applications where ordinary rubbers would fail.
Historically, the Buna-Werke factory, located near Auschwitz, produced NBR during World War II. This factory was part of IG Farben and sourced raw materials from nearby coalfields. While the history is complex, it shows that NBR has been an industrial backbone for decades.
Despite the different names, they all refer to the same versatile nitrile rubber. Its combination of chemical resistance, flexibility, and durability has made it indispensable in sectors such as automotive, aerospace, oil and gas, food, and medical industries.
Nitrile rubber sheets are known for their unique combination of strength, chemical resistance, and durability. They are designed to perform in conditions where ordinary rubbers often fail. Let’s break down their key features.
NBR sheets are mechanically tough, which makes them ideal for industrial use. Their tensile strength, tear resistance, elongation, and abrasion resistance set them apart from natural rubber.
| Property | Typical Range | Comparison to Natural Rubber |
|---|---|---|
| Tensile Strength | 3000–5000 psi | Higher, more durable |
| Tear Resistance | 200–400 pounds per inch (lpi) | Stronger under stress |
| Elongation at Break | 300–600% | Slightly less flexible than natural rubber |
| Abrasion Resistance | Excellent | Superior in high-friction environments |
They handle mechanical stress exceptionally well. Because of this, you often find NBR used for gaskets, seals, and conveyor belts where durability matters most.
One of the standout properties of NBR is its resistance to oils, fuels, and chemicals. They can withstand:
Aromatic oils like benzene, toluene, xylene
Mineral oils, gasoline, diesel
Hydraulic fluids used in machinery
They also resist many acids, alkalis, and solvents, which makes them reliable in chemical-heavy environments.
Limitations:
Avoid highly polar liquids such as ketones, amines, and ethers.
Polar solvents can cause swelling or degrade the sheet over time.
Quick Takeaway: It’s perfect where oil and chemical exposure is high, but not suitable for polar chemical environments.
NBR sheets perform well across a wide range of temperatures.
| Type | Operating Temperature | Notes |
|---|---|---|
| Standard NBR | −40°C to 108°C | Suitable for automotive and general industry |
| HNBR (Hydrogenated) | −40°C to 165°C | Enhanced heat, oil, and chemical resistance |
This makes NBR suitable for automotive, aerospace, and industrial applications where temperature fluctuations are common. They remain flexible even in cold conditions and stable in high heat.
NBR sheets are densely structured, creating a natural barrier against gases like oxygen, nitrogen, and carbon dioxide.
Ideal for sealing and gaskets in high-pressure systems.
Prevents gas leaks, making them reliable in industrial and automotive engines.
Their dense structure also enhances durability under stress, even in long-term applications.
Nitrile rubber sheets come in different types, each tailored for specific industrial needs. Choosing the right type depends on the application, chemical exposure, and temperature conditions. Here’s a closer look at the most common NBR variants.
Standard NBR sheets are widely used in everyday industrial and automotive applications. They offer a balance between mechanical strength, chemical resistance, and cost-effectiveness.
Typical uses include:
Automotive fuel and oil hoses
Seals and gaskets
Conveyor belts
Industrial linings
These sheets provide reliable performance in most moderate temperature and chemical environments, making them a versatile choice for general use.
HNBR, also known as Highly Saturated Nitrile (HSN), is a premium variant of NBR. Its structure is hydrogenated, which eliminates vulnerable double bonds and enhances its heat, chemical, and oil resistance.
| Feature | Standard NBR | HNBR (HSN) |
|---|---|---|
| Operating Temperature | −40°C to 108°C | −40°C to 165°C |
| Oil & Fuel Resistance | High | Very high |
| Chemical Resistance | Moderate to high | Excellent |
| Typical Applications | Gaskets, hoses, belts | O-rings, AC systems, industrial seals |
Common applications include:
Automotive air-conditioning O-rings
Industrial hydraulic seals
Timing belts and servo hoses
HNBR is ideal for high-performance environments where both chemical exposure and high temperatures are frequent.
XNBR is a modified form of NBR that includes carboxyl groups. This improves physical strength, abrasion resistance, and tensile properties, making it perfect for demanding industrial applications.
Applications of XNBR include:
High-performance gaskets and seals
Oil and fuel hoses under pressure
Industrial components requiring durability and toughness
This variant is preferred when enhanced mechanical properties are required without compromising chemical or temperature resistance.
Nitrile rubber sheets are highly versatile due to their chemical resistance, mechanical strength, and temperature stability. Industries ranging from automotive to food processing rely on these sheets to handle oils, fuels, and harsh chemicals. Let’s explore their key applications.
NBR sheets are widely used in the automotive sector because they can withstand fuel, engine oils, and hydraulic fluids without swelling or degrading.
Fuel and oil hoses: Flexible and durable, they transport gasoline, diesel, and lubricants safely.
Gaskets and seals: Prevent leakage in engines, transmissions, and fuel tanks.
O-rings and grommets: Provide secure sealing in high-pressure systems.
Conveyor belts and linings: Resist abrasion and mechanical stress in assembly lines.
The automotive industry values NBR for its combination of toughness and chemical resistance, ensuring safety and longevity.
In aerospace, materials must tolerate extreme temperatures and exposure to fuels or hydraulic fluids. NBR and HNBR sheets meet these requirements, making them suitable for aircraft fuel systems, hydraulic seals, and protective linings.
Fuel tank linings and seals: Withstand constant contact with aviation fuels.
Hydraulic systems components: Maintain flexibility and sealing under high pressure.
Protective gloves and gaskets: Provide chemical resistance in laboratory and maintenance tasks.
Their ability to maintain performance in harsh environments is a key reason aerospace engineers rely on NBR.
The oil and gas sector demands materials that resist petroleum products, greases, and extreme conditions. NBR sheets are ideal for pipelines, valves, and drilling equipment. Industrial manufacturing also benefits from NBR’s resistance to oils, acids, and mechanical wear.
Pipeline gaskets and seals for oil, LPG, and diesel pipelines.
Equipment linings in chemical plants.
Conveyor belts and industrial machine components that face heavy wear.
O-rings and high-pressure seals in hydraulic and pneumatic systems.
HNBR variants are particularly useful here due to their higher temperature tolerance and improved chemical stability.
Food-grade NBR sheets are FDA-approved, making them safe for applications involving fatty, oily, or greasy substances. They are easy to clean, anti-bacterial, and maintain hygiene standards.
Seals and gaskets in processing machinery.
Hoses and tubing for transporting oils or dairy products.
Protective mats and linings to prevent contamination.
Their chemical resistance and durability help maintain safe production environments while handling oils and food-grade fluids.
| Industry | Key Uses | Type of NBR Used |
|---|---|---|
| Automotive | Hoses, seals, O-rings, gaskets, belts | Standard NBR, HNBR |
| Aerospace | Fuel tank linings, hydraulic seals, protective gear | HNBR |
| Oil & Gas / Industrial | Pipeline gaskets, linings, machinery components | Standard NBR, HNBR, XNBR |
| Food & Beverage | Seals, hoses, linings, mats | Food-grade NBR |
Nitrile rubber sheets are everywhere, from cars to airplanes, factories to kitchens. Their versatility, strength, and resistance make them a reliable choice for industries that demand both durability and chemical stability.
The production of nitrile rubber sheets is a carefully managed process that directly affects their strength, flexibility, and chemical resistance. Understanding how NBR is made helps explain why it performs so well in demanding industrial, automotive, and aerospace applications.
Hot NBR is manufactured using emulsion polymerization at a temperature range of 30–40°C. At this heat level, the acrylonitrile and butadiene monomers react efficiently, forming a stable polymer latex. One key feature of hot NBR is the branching that develops within the polymer chains, which enhances its elasticity, flexibility, and mechanical resilience. This makes it ideal for products like hoses, gaskets, conveyor belts, and industrial linings, which need to withstand continuous stress and chemical exposure.
During the process, catalysts and radical initiators trigger the polymerization in a water-based medium. The reaction continues for several hours until the latex reaches the desired polymer consistency. The resulting polymer provides a strong foundation for rubber sheets that combine toughness with durability, ensuring they can endure oil, fuel, and mechanical wear in industrial environments.
Cold NBR, on the other hand, is produced at a much lower temperature, typically between 5–15°C. The reduced heat slows down polymer branching, creating a rubber that is more flexible at low temperatures and remains soft without losing mechanical strength. This variant is preferred in applications where extreme cold or low-temperature resilience is crucial, such as seals and gaskets used in refrigeration systems or cold-weather machinery.
The cold polymerization process follows similar steps to hot NBR, including the careful combination of acrylonitrile and butadiene in an emulsion, but the lower temperature ensures fewer branches form. As a result, cold NBR exhibits excellent low-temperature performance while maintaining good tensile strength, tear resistance, and chemical stability, making it suitable for highly specialized industrial applications.
Once the polymerization is complete, the latex goes through critical post-processing steps before it can be transformed into sheets, gloves, hoses, or other industrial components. The first step is monomer recovery, where steam removes unreacted acrylonitrile and butadiene, achieving nearly 100% recovery and ensuring minimal waste.
Next comes coagulation, where chemicals such as calcium nitrate and aluminum sulfate turn the latex into solid rubber. The coagulated material is then thoroughly washed and dried to remove residual chemicals, leaving a clean crumb rubber that can be processed further. Finally, the dried rubber is converted into sheets, molded products, hoses, O-rings, and other essential components, ready to meet industrial, automotive, or food-grade standards.
Each stage of production is designed to ensure consistent quality, high mechanical strength, and reliable chemical resistance, which are the hallmarks of premium nitrile rubber sheets. The careful control of temperature, branching, and post-processing ensures NBR sheets perform consistently across automotive, aerospace, industrial, and food processing applications, making them one of the most versatile synthetic rubbers available.
Nitrile rubber sheets come in standard, hydrogenated (HNBR), and carboxylated (XNBR) types, each designed for different industrial, automotive, and high-performance applications.
It offers superior resistance to oils, fuels, and chemicals, with higher tensile and tear strength, while remaining flexible enough for industrial use.
A nitrile rubber sheet is made from copolymers of acrylonitrile and butadiene, where acrylonitrile provides chemical resistance and butadiene adds flexibility and strength.
Standard nitrile rubber sheets work from −40°C to 108°C, while hydrogenated nitrile rubber sheets handle up to 165°C.
It is made via emulsion polymerization, followed by monomer recovery, coagulation, washing, drying, and finally conversion into sheets, gloves, hoses, or industrial parts.
Nitrile rubber sheets offer unmatched performance in demanding environments, from automotive engines to industrial machinery and aerospace systems. Their resistance to oils, chemicals, and extreme temperatures, combined with mechanical strength, makes them an essential material for countless applications. For high-quality nitrile rubber sheets that meet rigorous industry standards, Qingdao Hwation Rubber Co.,Ltd. provides a reliable range of products designed to deliver long-lasting performance and durability in every project.
