The present invention discloses a method for removing black spots from medicinal plastic bottles by injection blow molding, comprising: Step 1, preparing screw replacement material particles by mixing polypropylene, calcium carbonate and antioxidant in a high-speed mixer for 8–10 minutes, and extruding the mixture in an extruder at an extrusion temperature of 260–270°C; in the mixture, the weight proportion of polypropylene is 96–98%, calcium carbonate 1.5–4%, and antioxidant 0.2–0.5%; Step 2, before shutdown after production, withdraw the base of the injection blow molding machine and separate the injection head from the mold injection hole; Step 3, inject all normal production materials in the screw from the injection head with the screw replacement material particles, then shut down; Step 4, start up for production, add normal production materials, inject all screw replacement material particles from the injection head, then advance the base, connect the injection head to the mold injection hole, and start normal production. After using the screw replacement material particles, product quality and production efficiency are improved.

Country Code: CN

Application Number: CN202111417922.9