Vinylidene chloride copolymer resin composition and film thereof and extrusion processing method

A vinylidene chloride copolymer resin composition having excellent extrusion processability when in film formation and capable of manufacturing a film having excellent gas barrier property, tightness and boiling resistance is provided. The resin composition is composed of (by weight) more than 50% of vinylidene chloride copolymer(I) and less than 50% of vinylidene chloride copolymer(II), the reduced viscosity of the vinylidene chloride copolymer(I) is between 0.048 and 0.075, the reduced viscosity of the vinylidene chloride copolymer(II) is between 0.048 and 0.060, and the reduced viscosity of the vinylidene chloride copolymer(I) is greater than the reduced viscosity of the vinylidene chloride copolymer(II). The invention also relates to a film made of the resin composition and an extrusion processing method characterized by using an extruder with a vacuum hopper to extrude the resin composition.