Method for producing shaping material

A method for producing a shaping material by passing a raw-material resin that contains a cyclic olefin polymer in a molten state through an extruder,

• the extruder being equipped with a cylinder, a screw housed within the cylinder, a resin introduction port for introducing the raw-material resin into the cylinder, a resin discharge port for discharging the molten resin from the cylinder, a fluid injection port for injecting carbon dioxide or water into the cylinder between the resin introduction port and the resin discharge port, and a fluid discharge port for removing fluid in the cylinder by suction downstream of the fluid injection port and between the resin introduction port and the resin discharge port;
• the method comprising:
• injecting 1 to 6 parts by mass of carbon dioxide or water per 100 parts by mass of the raw-material resin into the cylinder from the fluid injection port while transporting the molten raw-material resin within the cylinder to bring carbon dioxide or water into contact with the molten raw-material resin, and discharging fluid in the cylinder from the fluid discharge port, thereby removing a volatile compound in the raw-material resin;
• and
• cooling and solidifying the molten resin discharged from the resin discharge port, wherein
• the rotation number of the screw during extrusion of the molten raw-material resin is 150 rpm or higher, and
• the oxygen concentration of the gas phase within the cylinder when the molten resin is brought into contact with carbon dioxide or water while being transported within the cylinder is 5% by volume or less.