History of Nitrile Rubber
For most of the early 1900s, prior to the outbreak of World War I, society industrialized at a rapid rate. This era saw the birth of the automobile industry and an increase in the use of oils in industrial machinery, as well as automotive and military applications. Before nitrile sheet rubber was developed, manufacturers had to make do with natural rubber, the supply and performance of which were erratic. The pursuit of developing a new synthetic oil-resistant rubber became imperative with the rapid industrialization of the Western Hemisphere.
After the war, Germany realized that it needed to make its own rubber supply. Even after the conclusion of the war the country was cut off from receiving new rubber stocks. During the years between the two world wars, German chemists worked to develop an elastomer that could be used in automotive applications without suffering degradation from oils and greases. They wanted something better than natural rubber, which tended to break down easily. They began developing synthetic elastomers. The oil-resistant rubber that was the result of their endeavors was called nitrile butadiene rubber, also known as Buna-N rubber. It became an instant success and is still widely used today.
1. How is Nitrile Rubber Produced?
Nitrile rubber is produced by combining butadiene and acrylonitrile into one single compound through a chemical reaction process. More specifically, “In the production of NBR, acrylonitrile and butadiene are emulsified in water and then polymerized (their single-unit molecules linked into large, multiple-unit molecules) through the action of free-radical initiators…With increasing acrylonitrile content, the rubber shows higher strength, greater resistance to swelling by hydrocarbon oils, and lower permeability to gases” (britannica.com). The resulting butadiene rubber material is not only chemical and oil resistant, but also features good tear and abrasion resistance. Compared to natural rubber, Buna-N rubber is stronger and more durable while still remaining elastic enough to be used as supports.
1(a). Physical Properties
As mentioned above, nitrile rubber is a copolymer of butadiene and acrylonitrile. Generally, nitrile sheets are stronger and more durable than natural rubber variations and can be strengthened by adjusting the amount of acrylonitrile mixed in during the production process. For instance, “Increasing acrylonitrile content leads to higher hardness, strength, abrasion resistance, heat resistance, and oil/fuel resistance and low temperature flexibility” (matweb.com). Despite this, however, nitrile sheet can be damaged by “ozone, chlorinated solvents, ketones, aldehydes, esters, and nitrogen-containing solvents.” It is also resistant to extreme high and low temperatures as hot as 248℉ and as cold as -22℉. Therefore, nitrile is more of an oil resistant rubber that is generally used for such purposes and would make a beneficial addition to areas with extreme temperatures.
1(b). Chemical Properties
Oil is not the only hazard that nitrile rubber guards against. In addition to petroleum oils, a nitrile sheet also exhibits enhanced levels of protection against other chemicals. It has excellent compatibility with chemicals such as ammonia, methyl alcohol, copper salts, detergents, mercury, potassium salts, and zinc sulfate but, as mentioned in physical properties, can be damaged by certain chemicals. These caustic agents can be very hazardous to existing non-nitrile objects. In contrast, they do minimal harm when paired next to Buna-N rubber. Keep in mind that Buna-N rubber is made in a variety of products and the concentration of the chemical needs to be considered when matching with the proper nitrile rubber sheet.
2. What is Nitrile Rubber Used For?
Nitrile sheet material is used to great effect in settings that may involve contact with grease, oil or chemicals. Due to its hardiness and physical durability, nitrile sheet can be used in more abrasive and heavy-duty applications compared to natural rubber while being versatile enough to benefit residential applications as well. It can be used industrially to provide long-lasting machinery components which might be exposed to fuel, lubricants and chemicals or residentially for water and grease resistance in the kitchen or other areas where these factors are also present.
2(a). Industrial Applications
The primary reason why OEMs (original equipment manufacturers) want nitrile rubber is because of its excellent oil resistance capabilities. A nitrile sheet can resist oils that are synthetic or organic in nature. For example, drops of motor oil can stay on a nitrile rubber surface for extended periods of time without degrading the material. As a result, it is often used in automotive applications such as garage workshops. An object made of butadiene rubber tends to last much longer than its natural rubber counterpart. For example, drops of motor oil can stay on a nitrile rubber surface for extended periods of time without degrading the material.
2(b). Residential Applications
Nitrile rubber can also provide the perfect choice for use in the kitchen. In this kind of environment, it is common for liquids such as cooking oil or food grease to spill or splatter, especially in large commercial kitchens. Using nitrile rubber sheeting for kitchen products ensures that they will not degrade as quickly and remain effective for longer. In addition, nitrile sheet can be used to settings such as laboratories, where spills involving caustic agents are possible, as well as being the perfect material for fuel hoses, gaskets, seals and more. It has come a long way since its war-forced beginning, now used in a huge variety of machinery and everyday settings.
If you have a need for an oil-resistant rubber that handles exposure to petroleum and chemicals very well, consider nitrile rubber for your application. Today, nitrile rubber is used in industrial applications such as oil and gas production, food processing, and automotive fields. These industries require seals and gaskets that can withstand the corrosive effects of various oils, greases, and chemicals. History has proven this synthetic elastomer to be invaluable.