EXTRUSION-MOLDED ARTICLE HAVING GOOD THERMAL STABILITY

摘要

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. This article is prepared by a process which comprises 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.degree.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.