MULTILAYER EXTRUDER, METHOD FOR PRODUCING MULTILAYER FILM, AND METHOD FOR PRODUCING MULTILAYER ORIENTED FILM

摘要

PROBLEM TO BE SOLVED: To provide a multilayer extruder for a multilayer film which can suppress thickness nonuniformity in the inner layer part of a multilayer film having at least three layers without enlarging the extruder.

SOLUTION: In the multilayer extruder 20, electric heaters 54 and 56 adjusting the temperature of a molten resin in a manifold 28 which can form the inner layer 3 of the multilayer film 2 are arranged to be closer to the manifold 28 side. In the heaters 54 and 56, heat insulating materials 60 and 62 are arranged to contact the opposite side (manifolds 26 and 30 side) of the manifold 28 to be heated. A controller 80 properly controls the voltages of the heaters 54 and 56 based on thickness data sent from a thickness detector 70 and delivers a voltage adjustment signal to control the temperature of the molten resin in the manifold 28 at a level of 0.1°C to the heaters 54 and 56. The thickness of the inner layer 3 of the multilayer film 2 is adjusted by changing the temperature of the molten resin in the manifold 28 and the flow velocity of the molten resin flowing in a channel 36.

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