The present invention relates to a process for preparing high molecular
weight polycarbonate resin, particularly to a process for preparing high
molecular weight polycarbonate resin, which conducts condensation
polymerization of low molecular weight amorphous polycarbonate prepolymer
prepared by transesterification of dialkyl(aryl)carbonate and aromatic
hydroxy compound and solid state polymerization within short time to
increase molecular weight. The present invention introduces condensation
polymerization to lower mole fractions of arylcarbonate existing in
unreacted diarylcarbonate, end groups of reaction by products of
polymerization degree less than 3, and polycarbonate prepolymer obtained
by transesterification, and thus can maximize molecular weight increase
of polycarbonate after solid state polymerization and remarkably reduce
time required for preparing polycarbonate of the same molecular weight.
In addition, since the present invention does not use toxic substance
phosgene, it has no danger and it can prevent deterioration, and it can
prepare high molecular weigh polycarbonate that can be used for injection
and extrusion.