PILOT-PLANT STUDIES AND MODELING OF A SEMIBATCH POLYESTERIFICATION PROCESS

A novel unsaturated polyester formulation was developed recently in our laboratories. The polyester resin, which was designed as a green-house glazing material, exhibited excellent optical properties and superior resistance to weathering conditions. This study describes the scale-up procedure followed in preparing the resin in a 200 L pilot plant reactor starting from its preparation in a 1 L reactor. The paper analyzes the major variables affecting the polyesterification process and presents a semi-empirical model capable of predicting the pilot plant kinetic data from laboratory reactor data. The model is based on a recently developed third order kinetic equation for the reaction of non-stoichiometric amounts of hydroxyl and carboxylic groups. The model quantifies the effects of reaction temperature and inert gas flow rate on reaction rate and provides a basis for the polyesterification process scale-up. The reaction temperature dependence is assumed Arrhenius, whereas the gas flow rate dependence is empirically determined as a function of the molar ratio of reactants to inert gas. Annlicafion of the model to commercial sized reactors will he hiohliohted. © 1990, Taylor & Francis Group, LLC. All rights reserved.