| 摘要 |
PURPOSE:To obtain a sheet having a high elasticity and a high strength by a method wherein an aromatic polyester composed of a dihydroxy compound shown by a specific general formula and other components is melted and molded into a sheet form, and the sheet is biaxially oriented in longitudinal and lateral directions and thermally treated in a specific temperature range. CONSTITUTION:An aromatic polyester composed of a dihydroxy compound shown by a general formula separately indicated; a diol component mainly containing an ethylene glycol; and a carboxylic acid component mainly containing a trephthalic acid is melted and molded into a sheet form. The sheet is biaxially oriented in a longitudinal direction by a factor of 2.0-4.5 and in a lateral direction by the same factor of 2.0-4.5. Furthermore, the sheet is thermally treated in a temperature range which is 50 deg.C or more higher than a glass transition temperature of the aromatic polyester but 30 deg.C lower than a melting point thereof. In addition, in the general formula, R<1>, R<2> independently represent alkylene group; (p) is 3 or 4; (q) and (r) independently represent 0 or an integer of 1 or more. |
