Development of heat shrinkable and flame-retardant EVA/CSM blends

A plastic (EVA) was blended with elastomer (CSM) with and without curatives. The elastomer phase (amorphous) contributed markedly to the shrinkability and most important is, took up a major amount of additive flame‐retarding agent thus not affecting much the heat shrinkability of the plastic i.e. as a whole the blend. When the elastomer phase was crosslinked the flame‐retardancy, due to a reduction of combustible volatile product, was increased. Additive flame‐retardants hamper the heat‐shrinkability of the blend to some extent depending on various factors such as blend composition, temperature, curing etc. The depression of shrinkability in the presence of flame‐retarding agent was less for the cured sample and elastomer‐rich blend compared with the uncured and plastic‐rich blend, respectively. It was found that with an increase in the cure time and elastomer content the shrinkability as well as flame‐retardancy was increased. At high temperature the sacrifice of the shrinkability in the presence of flame‐retardants increased, for a particular blend. The shrinkability and flame‐retardancy of a cured sample was higher than that of an uncured sample. The highest flame‐retardancy was obtained in the presence of Sb2O3/Chlorohor. Copyright © 2002 John Wiley & Sons, Ltd.