Continuous process for producing thermoplastic moulding compounds

摘要

The invention concerns a process for continuously producing impact-resistant modified thermoplastic moulding compounds which contain a rubber-elastic soft phase dispersed in a vinylaromatic hard matrix. In a first reaction zone the rubber necessary for forming the soft phase is polymerized anionically in solution substantially without re-mixing until the reaction is complete. The rubber is fed, directly or after the addition of a breaking or coupling agent, to a second reaction zone in which it is polymerized until the phases are inverted with the addition of an amount of vinylaromatic monomer sufficient for phase inversion and a further anionic initiator. In a third reaction zone polymerization is terminated anionically with as many vinylaromatic monomers as are required to form the impact-resistant modified thermoplastic moulding compound.