MULTILAYER EXTRUSION MOLDING APPARATUS, METHOD FOR MANUFACTURING MULTILAYER FILM AND MULTILAYER STRETCHED FILM

摘要

PROBLEM TO BE SOLVED: To provide a multilayer extrusion molding apparatus of a multilayer film which can eliminate thickness unevenness of an outermost layer member and an inner layer member of a multilayer film of at least three layers by performing fine temperature control of a melting resin.

SOLUTION: The thickness of the outermost layer of a multilayer film 2 is roughly adjusted by the moving of choke bars 44 and 46 by the advancing and retreating of choke bar adjusting bolts 48 and 50. The choke bars 44 and 46 are heated and the resin temperature of a melting resin which flows in passages 34 and 38 is changed by controlling the quantity of heat of rod-shaped electric heaters embedded in each of bolts 48 and 50. Thereby, the minute thickness adjustment is performed. A controller 80 controls the voltage of the rod-shaped electric heaters appropriately based on the thickness data sent out from a thickness detection device 70, and sends out a voltage adjustment signal which controls the resin temperature of the melting resin to the rod-shaped electric heaters.

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