The 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.
An inflatable boat is a lightweight boat constructed with its sides and bow made of flexible tubes containing pressurized gas. For smaller boats, the floor and hull beneath it is often flexible. On Allmand Inflatable boats most are made with double hull construction made from fiberglass and called rigid hull inflatable boats. With others the floor can consist of three to five rigid plywood or aluminum sheets fixed between the tubes but not joined rigidly together so the boat can be deflated and folded for transportation. This type is common with flood rescues where a number of boats need to be transported by truck and quickly deployed.
In most cases the transom is rigid, providing a location and structure for mounting an outboard motor. Some inflatable boats have been designed to be disassembled and packed into a small volume, so they can be easily stored and transported to water when needed. Here the boat when inflated is kept rigid crossways by a foldable removable thwart. This feature allows such boats to be used as life rafts for larger boats or aircraft, and for travel or recreational purposes. Other terms for inflatable boats are "inflatable dinghy", "rubber dinghy", "inflatable", "inflatable rescue boat" or "rubber duck" It is also used in roofing materials, and as a surface coat material on radomes, owing to its radar-transparent quality.
Hypalon is also used in the construction of the decking of modern snowshoes, replacing neoprene, as a lighter, stronger alternative. Hypalon has become the common name for all kinds of CSM, even though DuPont was not the only manufacturer. Tosoh Corporation of Japan produces CSM under the trade names Toso-CSM and extos. 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 also its related product, Acsium. The plant closure was delayed until April 20, 2010, in response to customer requests.