| 摘要 |
PROBLEM TO BE SOLVED: To efficiently produce many brands by supplying polyester and powder particles to a twin-screw extruder to knead them to form a particle-containing film layer and separately mixing virgin and recovered polyesters in a molten state to form other layer and laminating both layers to subject them to co- extrusion. SOLUTION: Powder particles are supplied to a vent type twin-screw extruder 21 for forming an A-layer from a supply port separate from supply ports of molten polyester and polyester chips and kneaded with molten polyester and polyester chips supplied to the extruder 21 while weighed by measuring feeders 24, 25. For example, continuously polymerized molten polyester and polyester obtained by recovering film refuse for a B-layer are weighed by gear pumps 28, 18 to be kneaded in a kneader 30 and/or a stationary mixer 31 and the kneaded mixtures are melted and extruded to be weighed by gear pumps to be allowed to meet with each other and kneaded by the kneader 30 to be combined with each other to be supplied to a multilayered die 32. A non-stretched film is produced from the extruded polymer and successively stretched to obtain a biaxially oriented polyester film. |
