Full definition
Chloroprene Rubber (CR), also known as Neoprene, is a versatile synthetic rubber first synthesized by DuPont in 1932. Its chemical structure, polychloroprene, gives it unique properties that make it suitable for a wide range of industrial applications. CR exhibits a balanced combination of physical and chemical properties, which include moderate resistance to oils and fuels, making it superior to natural rubber (NR), styrene-butadiene rubber (SBR), and ethylene propylene diene monomer (EPDM) but not as resistant as nitrile (NBR) or fluorocarbon (FKM) rubbers. The inherent flame retardancy of CR is notable, as it possesses a Limiting Oxygen Index (LOI) greater than 26%, enabling it to self-extinguish due to its chlorine content, which is approximately 36%. This makes it particularly valuable in applications where fire safety is a concern.
In terms of environmental resistance, Chloroprene Rubber has excellent ozone and weather resistance, which allows it to perform well in outdoor settings. Its dynamic performance also stands out in applications requiring flexibility and resilience under mechanical stress. The temperature tolerance of CR ranges from -35°C to +100°C for continuous use, with the ability to withstand intermittent temperatures up to +120°C. Its hardness can vary from 30 to 90 Shore A, with tensile strength ranging from 15 to 25 MPa and elongation at break between 200% and 600%, depending on the specific grade and formulation used.
Chloroprene is classified under ASTM D2000, with grades such as BC for standard applications and BE for higher temperature environments. Various grades of CR are available, including W-types for general purposes, GN/GNA for low-temperature flexibility, and AC, which serves as a base for adhesives. However, CR does have limitations; it can be attacked by aromatic solvents and chlorinated hydrocarbons, which may restrict its use in certain chemical environments. The cost of Chloroprene Rubber typically ranges from $3 to $5 per kilogram, making it a moderate investment for many applications.
In practical applications, CR is commonly used as a belt body compound, often alongside EPDM, in expansion joints, bridge bearings, automotive hoses, cable jacketing, wetsuits, industrial sheets, and as a base for contact adhesives. Notable manufacturers include Denka from Japan, Pidilite from India, and Lanxess with their Baypren products.