| abstract |
A thermally stable extrusion-molded article characterized by (1) consisting of a substantially linear polyester in which at least 90 mol% of the total recurring units consist of tetramethylene 2,6-naphthalate units, (2) having a density not in excess of 1.318, and (3) being in the unstretched state. n This article is prepared by extruding a melt of a substantially linear polyester in which at least 90 mol% of the total recurring units consist of tetramethylene 2,6-naphthalate units into the form of a molded structure, and cooling the extruded molded structure to room temperature, wherein during the period in which the extruded molded structure is cooled from at least 75%C. to room temperature, the cooling of the molded structure is performed rapidly so that the density of the molded structure does not exceed 1.318. |