An epoxidized granular thermoplastic polymer which comprises a shell-like surface
layer insoluble in toluene at 25 C. is formed on the polymer, and a process
for the production of the epoxidized granular thermoplastic polymer characterized
in that the process comprises: the first step of epoxidizing a granular thermoplastic
polymer in a water medium in the presence of an epoxidizing agent or the epoxidizing
agent and a solvent for accelerating an epoxidation reaction and a phosphoric acid
series compound; the second step of the washing with water, or the neutralization
and washing with water of the epoxidized granular thermoplastic polymer; and the
third step, if necessary, of removing the solvent for accelerating epoxidation
reaction which may be used in the first step, as well as a process for the production
of an epoxidized thermoplastic polymer, characterized in that under the condition
in which thermoplastic polymer (A) in the solid-state is dispersed or suspended
in water (B), the thermoplastic polymer (A) is epoxidized by a peroxide (C) with
the dispersed or suspended state maintained.
