VERFAHREN ZUR HERSTELLUNG VON THERMOPLASTISCHEN FORMMASSEN AUF BASIS VON VINYLPOLYMERISATEN

• Main Authors: HEDERICH,MANFRED, WASSMUTH,GERD,.DR, ULLRICH,MARTIN, WINGLER,FRANK,.DR, LIEBIG,LOTHAR,.DR
• Format: Patent
• Language: German
• Published: 21.12.1978
• Edition: 2
• Subjects: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CHEMISTRY; COMPOSITIONS BASED THEREON; MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVINGCARBON-TO-CARBON UNSATURATED BONDS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; THEIR PREPARATION OR CHEMICAL WORKING-UP; THEIR RELEVANT APPARATUS; TRANSPORTING

A process for the production of thermoplastically processible moulding materials based on vinyl polymers of high chemical and molecular uniformity and having residual monomer contents of less than 0.1 mol % which comprises the steps of: (i) mass homogeneous phase polymerization of at least one vinyl monomer in a stirred continuously charged tank reactor to a conversion of from 25 to 60 mol %; (ii) directly concentrating the syrup consisting of residual monomers and vinyl polymer dissolved therein obtained from step (i) in a spiral tube evaporator at a temperature of from 60 DEG to 250 DEG C. and at a pressure of 100 m bar to 35 bar to obtain a solid content of vinyl polymer of from 40 to 90 mol %; (iii) directly charging the concentrate obtained from step (ii) to the inlet zone of a screw evaporator which consists of at least two sequential zones in order to effect further concentration, in which a first zone at a pressure of from 10 to 300 m bar and at a temperature of from 100 DEG to 250 DEG C. concentrates the vinyl polymer to a solid content of from 80 to 99 mol-%, and each subsequent zone at a pressure of 1 to 200 m bar and at a temperature of 150 DEG to 250 DEG C. concentrates the vinyl polymer to a solid content of at least 99.