| 摘要 |
PURPOSE:To obtain liquid crystal-forming polyesters that will provide a polyester molded item, particularly, a fiber or a sheet that has a high strength and a high Yound'g modulus, by introducing substituents having specific sizes in specified quantities to aromatic rings. CONSTITUTION:Polyesters consisting of compounds of the formulaeI-IV (wherein l-n each are 0 or a positive integer provided that 1<=l+m+n<=4 should be satisfied, and X-Z which may be the same or different each represent a radical with a valance of 1 provided that when the numbers of atoms other than hydrogen in the radicals are designated x, y and z respectively, 2<=nx+ my+lz<=8 should be satisfied) in such a ratio of 20-60mol% compoundI, 5- 20mol% compound II, 5-35mol% compound III and 20-40mol% compound IV is heated to a melted liquid crystal state, and is extruded. This may be subjected to heat treatment at a temperature >=150 deg.C under tension or a slackened condition. Thus fibers or films can be obtained. |
