How Is Nitrile Rubber Made?

Nitrile is often used to make cleaning gloves.

Nitrile rubber is a common material in everyday life. One of the most familiar uses of this material is in blue rubber medical gloves, but the rubber is found elsewhere, as well. This synthetic rubber is also used to make fuel and oil hoses, shoes, floor mats and many other common objects. The rubber is sold under trade names such as Krynac, Europrene and Nipol.

Properties

Nitrile rubber is commonly used in the oil industry due to its resistance to fuel and other chemicals. It is a resilient material often used in examination, lab and cleaning gloves, and it is also useful for seals in vehicles. Since nitrile rubber is resistant to a wide range of temperatures, it works well in areas where ordinary rubbers would break down. Nitrile rubber is more chemically resistant than natural rubber but less flexible and weaker.

Benefits

Synthetic rubbers can be used in many situations where natural rubber would not be feasible. People with latex allergies often find that using cleaning or medical gloves made from nitrile does not cause a reaction. This material can also be used in areas where temperature, acid, petroleum exposure or other environmental hazards would preclude use of natural rubber.

Composition

Nitrile rubbers are copolymers of two materials, called butiadiene and acrylonitrile. Butiadene is often produced from acetylene or ethyl alcohol. Acrylonitrile is made from acetylene or ethylene oxide and hydrogen cyanide. The two materials are combined in a stainless steel container using either hot or cold polymerization.

Manufacturing

Once the monomers have combined to form the nitrile copolymer, the latex material passes through a series of filters. This removes undesirable solids from the mix. The material is then blended with an antioxidant material to stabilize it. Coagulating agents are added to solidify the material, which is finally washed and dried to produce crumb rubber, the basic form of nitrile rubber. Crumb rubber can be liquified at its destination and used to produce nitrile rubber materials.

Considerations

Nitrile rubber is not suitable for all uses. Like natural rubber, it can be damaged by aromatic hydrocarbons, ozone from oxygen exposure, ketones, sunlight and other environmental factors. These problems are usually reduced to some degree by the inclusion of other materials, such as polyvinyl chloride, or by hydrogenating the rubber. Hydrogenated nitrile rubber is strong, elastic and more resistant to abrasion.

References

• Texas A&M University, College of Engineering: Nitrile Rubber
• Scribd: Industrial manufacturing of Nitrile Rubber
• MERL: Rubber Selection -- A Guide to Outline Properties