Full definition
Flame-resistant neoprene, known scientifically as polychloroprene (CR), exhibits remarkable flame-retardant properties due to its high chlorine content, approximately 36% by weight. When exposed to fire, the chlorine within the material releases hydrochloric acid (HCl) gas, which is dense and non-flammable. This gas acts to suppress flame propagation by diluting oxygen and inhibiting free radical formation, thereby enabling CR to achieve UL 94 V-0 or V-1 ratings without necessitating additional flame-retardant additives. However, the performance can be further enhanced with additives like aluminum trihydrate (ATH). The material's oxygen index (LOI) ranges from 26% to 32%, which is significantly higher than the 17% to 20% found in natural rubber (NR) and styrene-butadiene rubber (SBR), both of which are more flammable and less suitable for applications where fire resistance is critical.
One of the most notable features of flame-resistant neoprene is its ability to self-extinguish within seconds after the ignition source is removed, making it a preferred choice for various industrial applications. For example, in electrical applications, it is often utilized for cable jacketing (NEC types SO/SOW), providing both mechanical protection and flame resistance. In the mining industry, flame-resistant neoprene is used in conveyor belts that comply with MSHA regulations, ensuring safety in high-risk environments. Additionally, it is employed in fire-resistant gaskets and seals, components in transit vehicles that adhere to NFPA 130 standards, and in military and aerospace applications where non-propagating flame behavior is essential.
In contrast, other elastomers such as EPDM, NR, and SBR cannot achieve similar levels of flame resistance without substantial additive loading, which may adversely affect their mechanical properties. This makes flame-resistant neoprene a superior choice for any application requiring both durability and flame resistance, ultimately leading to enhanced safety and performance.