CSM – Chlorosulfonated Polyethylene
Chlorosulfonated polyethylene (CSM) is widely known as Hypalon®.1 It can be considered a superior type of chloroprene, having better heat and chemical resistance.
CSM grades usually contain 20 - 45 percent chlorine which provides excellent resistance to ozone, UV, weathering, and chemicals. This includes oxidizing agents, hot water (when cured) and corrosive chemicals. It also has good resistance to dry heat up to 150°C, low flammability, low gas permeability, and good electrical properties. However, it has poor/fair fuel resistance and its low temperature properties are generally limited, depending on the chlorine content of the CSM grade. Furthermore, its compression set is rather low.
COMMERCIAL CSM Elastomers
Important manufacturers and suppliers of chlorosulfonated polyethylene elastomers are Tosoh ad Lianda.2
CSM elastomers are generally useful in electrical applications and as protective coatings against corrosive environments. Its excellent UV stability makes it also useful as a material for outdoor applications, like roof sheeting and pond liners. Typical applications include acid resistant tank linings, static seals, membranes, fabrics, hoses and electrical cable jacketing.
The typical working temperature range is between -20°C and +125°C.
- Hypalon® is a registered trademark of DuPont Performance Elastomers.
In April 2010, the world's largest chlorosulfonated polyethylene elastomer producer, DuPont Performance Elastomers, ceased production of Hypalon. This move created a huge shortage in the world's chlorosulfonated polyethylene elastomer market and for end users of CSM. Japan and China are now the largest suppliers of CSM elastomers, with Japan being the largest exporter.