| 摘要 |
PROBLEM TO BE SOLVED: To obtain an arom. polyester film improved in clarity, tensile strength, modulus, and heat resistance by removing a solvent from a soln. of an arom. polyester contg. specific side-chain-substd. arom. dicarboxylic acid units and arom. diol units. SOLUTION: An arom. polyester contg. side-chain-substd. arom. dicarboxylic acid units of formula I (wherein R is methyl or ethyl), side-chain-substd. dicarboxylic acid units of formula II in a ratio of I/II of (80/20)-(5/95), and arom. diol units of formula III or IV and having an intrinsic viscosity of 0.5-3.0 d l/g is dissolved in a concn. of 1-20 wt.%, pref. 2-10 wt.%. still pref. 3-7 wt.%, in a good solvent (e.g. chloroform). The resultant soln. is cast on a glass plate, a Teflon plate, etc., dried by evaporating the solvent at room temp., and annealed at 100-200 deg.C to completely remove the solvent, thus giving an arom. polyester film having a light transmission (at a wavelength of 800-420 nm) of 70 % or higher, a light transmission (at a wavelength of 370 nm) of 10% or lower, a tensile strength of 8 kg/mm<2> or higher, and a tensile modulus of 200 kg/mm<2> or higher. |
