Abstract:
Unsaturated polyester resins have traditionally been manufactured in batch
operations, and reactor design is an important factor. Typical polyester
reactors are constructed at a length/diameter ratio of approaching unity,
and are equipped with a single pitched (axial flow) turbine whose diameter
is about 40 percent of that of the tank. Reactor cooling capability is the
single most critical factor determining the plant's capacity, because the
polymerisation is highly exothermic. Polyester reactors usually contain
spiral-wound, water-filled cooling coils for this purpose.
To promote a steady reaction rate and to help maintain a homogenous product,
some of the reactants may be introduced continuously or in discrete
additions, as the reaction proceeds. The reaction time varies between six
and thirty hours, being strongly dependent upon the nature of the raw
materials.
