Multi-step thermoplastic vinyl aromatic cpd. copolymerisation - initiated by dissociating radical and heat in first step and by heat in second step

摘要

Thermoplastically workable copolymers are produced by a multi-step process. In 1st step, a mixt. contg. vinyl aromatics and further monomers is copolymerised continuously in a flooded, ideally mixed-through tank reactor. In 2nd step, continuous copolymerisation is continued in a 60-85 vol% filled reactor. Novelty consists in initiating polymerisation in 1st step with an initiator dissociating into radicals and having half-life 1/20 of the average dwelling time at the prevailing polymerisation temp. The heat of polymerisation is abstracted through the cold-charged monomers and through the reactor wall. In 1st step, 50-100 mol.% of the monomer conversion is initiated by the initiator and 0-50 mol% by heat. In 2nd step, monomer conversion is initiated by heat and heat-abstraction is achieved by vapour-cooling. The copolymers can be injection-moulded, deep drawn or pressed to articles such as dishes, armatures, household articles, internal car fittings, boat-building, optics and electronics, and also worked to foils and containers for packing food and pharmaceuticals.