Production of polyester film

Abstract

Abstract PURPOSE:To obtain a uniform film having a high Young's modulus, by a method wherein, when a polyester constituting an optically anisotropic molten material is extruded through a slit fitted with a plate form porous body having a plurality of small gaps on the ejection side, the ejection-side surface of the porous body is heated, and the portions of the molten material extruded through adjacent small gaps are bonded to each other. CONSTITUTION:When a polyester having a property of forming an optically anisotropic molten material is melt-extruded through a slit to produce a film, the plate form porous body having a plurality of sall gaps is internally provided at least on the ejection side of the slit, and the polyester is melt-extruded while heating at least the ejection-side surface of the porous body so that the portion of the molten material extruded through a given one of the small gaps is bonded to the portions of the material extruded through the adjacent ones of the small gaps to form a continuous layer. Accordingly, a uniform film having excellent mechanical properties in respect of not only the machine axis direction but directions perpendicular to the machine axis can be obtained.

Inventors

• 👤 Yasuji Hirabayashi
• 👤 平林　保治
• 👤 Yasuhiko Segawa
• 👤 瀬川　泰彦
• 👤 Toshinobu Azumi
• 👤 安住　敏宣

Bibliographic Details