Hypalon (Chlorosulfonated Polyethylene or CSM) is a synthetic rubber. Although DuPont ceased production of the brand name “Hypalon” in 2010, the material continues to be manufactured globally by various chemical companies under the generic name CSM.
Major Advantages
- Superior Environmental Resistance: CSM is renowned for its excellent resistance to UV radiation, ozone, and atmospheric aging, making it a standard for roofing membranes and high-end marine products.
- Outstanding Abrasion Resistance: It is highly durable and resists mechanical wear and tear better than most general-purpose elastomers, which is critical for industrial rollers and protective gear.
- Excellent Chemical Stability: It handles a broad spectrum of harsh chemicals, including powerful oxidizing acids (nitric, sulfuric, and chromic), alkalis, and salts.
- Color Stability and Aesthetics: Unlike many synthetic rubbers that require carbon black for reinforcement, CSM can be pigmented in a wide variety of colors without sacrificing its mechanical properties or weather resistance.
- Flame Resistance: It is naturally self-extinguishing and will not support combustion, a vital property for safety-critical electrical and automotive components.
- Operational Temperature Range: It remains functional across a wide temperature spectrum, typically from -22°F to +266°F (-30°C to +130°C) , with specialty grades surviving short periods up to 375°F (190°C).
- Low Moisture Absorption: Its high impermeability to water and gases makes it ideal for waterproof coatings and marine inflatables.
Limitations
- High Cost: CSM is more expensive than general elastomers like Neoprene or EPDM, often limiting its use to high-performance or professional-grade equipment.
- Chemical Incompatibility: It is generally attacked and degraded by concentrated oxidizing acids, aromatic and chlorinated hydrocarbons, esters, and ketones (such as acetone).
- Poor Compression Set: Compared to Viton (FKM), standard CSM typically has lower resilience and a poorer compression set, meaning it may not return to its original shape as effectively after prolonged pressure.
- Specialized Repair: For products like inflatable boats, CSM requires more involved repair processes using specialized adhesives compared to simpler materials like PVC.
