Process for preparing polymeric material with microwave
AssigneeE. I. Du Pont de Nemours and Company
InventorsPeter J. Goethel, Richjard W. Lewis, Wilford J. Teerlink
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Abstract
Process and apparatus, in which a stream of liquid reactants is heated in a resonant microwave cavity operating in a TM.sub.0n0 mode and then provided with sufficient time in an annular plug flow reactor to complete the reaction results in improved time-temperature uniformity for all volume elements of the stream and are particularly suited for production of polyurethane prepolymer. A special cleaning method is provided for removing polymeric residues from the equipment with a solution of a monofunctional secondary amine in an organic solvent.
Claims4
An improved process for making a polymeric material which comprises mixing reactants, optionally in the presence of a solvent, to form a liquid reactant stream, heating the stream and providing sufficient reaction time to form the polymeric material, wherein the improvement comprises
- rapidly heating the reactant stream in a microwave resonant cavity operating with microwave energy producing a TM.sub.0n0 mode with minimum heating at radial boundaries of the stream, and
- continuing the reaction as the stream advances substantially in plug flow through an annular zone of a volume controlled to provide a total residence time from the time the reactant stream enters the microwave cavity until the time product is removed from the annular zone that is constant and independent of mass-flow.
Dependencies are inferred from the claim text.