Method for extruding polymer blend resin

The present invention provides a method for extruding polymer blend resin which is capable of satisfying performances which are necessary as a resin-coated metal can even when the resin-coated metal can is produced through an extremely stringent working such as drawing, deep drawing, bend-elongation by drawing, stretching or ironing. After feeding thermoplastic resin A to a biaxial extruder through a first raw material feed port of the extruder, the thermoplastic resin A is plasticized in a molten state and is subjected to degassing under reduced pressure. Thereafter, thermoplastic resin B whose melting temperature or softening temperature is lower than a melting temperature or a softening temperature of the thermoplastic resin A is fed to the extruder through a second raw material feed port. Assuming Lb as a length of a blending zone and D as a screw diameter of the extruder, the thermoplastic resin B is blended with the thermoplastic resin A in the blending zone of Lb/D=0.5 to 5.0 and the blend resin is extruded from the extruder.