| 摘要 |
PROBLEM TO BE SOLVED: To provide a biaxial extrusion apparatus in which temperature of a resin to be melted and extruded is kept stably in order to reduce the number of carboxyl groups on the surface of a film or a sheet of polyester and enhance hydrolysis resistance thereof so that a resin having low haze property and excellent weather resistance is produced and to provide a method for producing a film.SOLUTION: An extruder 100 for extruding a molten resin includes: a cylinder having an extrusion port; two screws which are arranged in the cylinder and each of which has 100 mm or larger outside diameter &phgr;; a cooling system that has a first cooling medium supply and discharge port and a cooling medium flow passage, through which a cooling medium for exchanging heat with the molten resin in the cylinder is circulated, and that is disposed on the wall of the cylinder; temperature detection means 50 which is disposed on the downstream side of the extrusion port of the cylinder in a circulation direction of the molten resin and on the upstream side of a film production apparatus 40 for molding the molten resin extruded from the extrusion port and which is used for detecting temperature of the molten resin extruded from the extrusion port; and resin temperature control means 60 in which the amount of the cooling medium to be supplied to the first cooling medium supply and discharge port is adjusted so that a temperature difference between the detected temperature of the molten resin and a preset temperature is controlled to be equal to or lower than a predetermined threshold. |
