In polymer science, Hypalon is a trademark for chlorosulfonated polyethylene (CSPE) synthetic rubber (CSM) noted for its resistance to chemicals, temperature extremes, and ultraviolet light. It was a product of DuPont Performance Elastomers, a subsidiary of DuPont.
Along with PVC, CSM is one of the most common materials used to make inflatable boats and folding kayaks. It is also used as a single-ply roofing membrane and as a surface coat material on radomes owing to its radar-transparent quality.
DuPont Performance Elastomers announced on May 7, 2009, that it intended to close its manufacturing plant in Beaumont, Texas, by June 30, 2009. This was DPE's sole plant for CSM materials. The company was therefore exiting the business for Hypalon and its related product, Acsium. The plant closure was delayed until April 20, 2010, in response to customer requests.