A process utilizing PET as a reactive constituent to manufacture other
polymers containing the pre-condensed moieties by the rapid
transesterification of the condensation polymer with a pre-made modifying
polymer containing the desired mix of other monomers. The process
involves as a first step the manufacture of a modifying polymer
containing the desired mix of acids and alcohols to a specific molecular
weight such molecular weight dependent on the desired final level of
utilized condensation polymer and the finished molecular weight. The
second step of the process involves the rapid buildup of molecular weight
and/or polymer uniformity by the rapid transesterification of the
condensation polymer with the modifying polymer. The second step can be
performed in any suitable vessel including an extrusion line. The process
has the advantage of greatly reduced cycle times over other condensation
polymer utilization processes such as the recycling of PET into other
materials.