Twin screw extruder, method of making aromatic polycarbonate using a twin screw extruder, and method of removing volatiles from an aromatic polycarbonate melt

A method of kneading components into an aromatic polycarbonate using a twin screw extruder, wherein the component is at least one component selected from the group consisting of a catalyst deactivator, devolatilizing agent and resin additives, characterized in that the extruder comprises at least one module (A) consisting of a kneading unit, a material seal unit which is a seal ring unit or a back flight unit, a back kneading unit and a full-flight unit which are arranged in order from an upstream side to a downstream side, and in that the method comprises the steps of:

• (1) supplying the components to the area of the kneading unit of the module (A) of the twin screw extruder;
• and
• (2) discharging volatile components from the area of the full-flight unit of the module (A) of the twin screw extruder.

A method of removing volatile components from a twin screw extruder comprising at least one module (A) consisting of a kneading unit, a material seal unit which is a seal ring unit or a back flight unit, a back kneading unit and a full-flight unit which are arranged in order from an upstream side to a downstream side, together with water vapor by supplying water to the twin screw extruder and kneading it into a molten aromatic polycarbonate, the method comprising the steps of:

• supplying water to the twin screw extruder at an absolute pressure of 0.3 to 10 MPa;
• and
• discharging water vapor and volatile components from the extruder at an absolute pressure of 1.333×10 Pa to 1.013×105 Pa.