PURPOSE: To prevent oxidation of resin and obtain a molded item having improved appearance and quality by feeding inert gases into between a raw resin feed port and a parison extruding port of an accumulator and melting the resin to move and extrude it.
CONSTITUTION: A resin 3 is melted and extruded by an extruder 1 so that a predetermined amount of resin is stored in an accumulator 2 comprising a plurality of constituent members, following which it is extruded by a piston 26 to form parison. And then inert gas 4 is fed into resin passages 13a, 13b between a feed port 15 of the extruder 1 for the resin 3 and a parison extruding port 37 of the accumulator 2. And the air in the resin passages is replaced with the inert gas. Under such conditions, the resin is melted, transferred, and extruded. Further, when the resin is heated and cooled, inert gas is fed into the passages 13a, 13b which are in contact with the air.
MUROFUSHI NORIYUKI
YAMAGUCHI MASUO
MORISHITA KENICHIRO
