METHOD FOR THERMALLY STABILIZING POLYCARBONATE RESIN OR POLYESTER RESIN

摘要

PROBLEM TO BE SOLVED: To provide a new method for thermally stabilizing a polycarbonate resin or polyester resin. SOLUTION: This method for thermally stabilizing the polycarbonate resin or polyester resin is characterized by adding 20 to 1,800 ppm of phthalic acid and 2 to 180 ppm of tannin to the polycarbonate resin or polyester resin. When the polycarbonate resin or polyester resin is thermally melted, the lowering in the mol.wt. of the polycarbonate resin or polyester resin can be controlled to achieve thermal stability.