Continuous process for the preparation of highly stable, finely divided, low viscosity polymer polyols of small average particle size

A CONTINUOUS PROCESS FOR THE PREPARATION OF HIGHLY STABLE POLYMER POLYOLES, FINALLY DIVIDED WITH LOW VISCOSITY OF SMALL AVERAGE PARTICLE SIZE WHERE IN THE FIRST STEP AN INTERMEDIATE IS PREPARED BY AN ESRILE OF A SEMI-ESRILE MIXTURE OF (2) A POLYOXYALKYLENE POLYETHER POLYOL AND (3) A MACROMER IN THE PRESENCE OF (4) A FREE RADICAL STARTER, (5) A SOLVENT WITH AN OPTIONALLY MODERATE CHAIN ​​TRANSFER ACTIVITY (6) A REACTION MODERATOR AT A TEMPERATURE OF AT LEAST 100 C, SO THAT THE INTERMEDIARY CONTAINS A HIGH LEVEL OF MACROMERO, AT LEAST AROUND 12% AND PREFERABLY AT LEAST AROUND 15% WITH RESPECT TO THE POLYOL MIXTURE AND THE SOLID CONTENT OF THE INTERMEDIARY IS LESS THAN AROUND 30%, PREFERABLY LESS THAN AROUND 25%, AND AT LEAST AROUND 15%, IN WEIGHT. THAT WORKS AS A SEED FOR POSTERIOR POLYMERIZATION, IS REACTED BELOW IN ONE OR MORE SERIAL EXCITED DEPOSIT REACTORS WITH A MIXTURE OF STYRENE AND ACRYLONITRILE IN A POLYOL AND OPTIONALLY A SOLIDENT AND INITIATOR MACROMER, PRESENTER THEY ARE DISTRIBUTED AMONG THE REMAINING REACTORS.