PROCESS FOR PRODUCING BROMINATED BUTYL RUBBER

There is provided a process for the preparation of cements comprising aliphatic mediurn and at least one brominated butyl rubber. First, a butyl rubber is provided where the butyl rubber comprises 5 to 30 wt-% of at least one butyl rubber; 0 to 5 wt-% of water and an aliphatic medium. Then, the butyl rubber or the butyl rubbers contained in the butyl rubber cement are brominated by a continuous process with elemental bromine in the presence of an added aqueous oxidizing agent in order to obtain a heterophasic mixture having a cement and an aqueous phase. The oxidizing agent is an aqueous solution of hydrogen peroxide comprising 20 to 60 wt-% of hydrogen peroxide. Finally, the pH of the aqueous phase is adjusted using a base to 6 to 13, then the cement is separated from the aqueous phase or the heterophasic mixture is separated to obtain the cement and an aqueous phase and the cement is washed with an aqueous mixture. L'invention concerne un procédé à efficacité énergétique correcte, respectueux de l'environnement pour la préparation de caoutchoucs butyle bromés, qui utilise un agent de bromation et un agent d'oxydation afin d'améliorer l'utilisation de brome contenu dans l'agent de bromation. Dans un mode de réalisation préféré, un milieu commun pour la polymérisation en solution et la bromation consécutive du caoutchouc est utilisé.