| 摘要 |
A modified polyester having excellent mechanical properties such as tenacity which emits only a small amount of a gas by decomposition during use at elevated temperatures for a long period of time and only a small amount of a sublimate in the course of melting it and which is suitable particularly for use as the material of a molding for an electric or electronic component, or a packaging material such as film, sheet or container, characterized by its formation from: (A) an acid component mainly comprising terephthalic acid, 2,6-naphthalenedicarboxylic acid or a lower alcohol ester thereof, (B) a diol component mainly comprising an alkylene glycol having 2 to 8 carbon atoms, and (C) an aromatic sulfonic acid compound of the following general formula (1): (1) HO(RO)n-Ar-SO3M wherein Ar represents a benzene or naphthalene ring, n represents an integer from 1 to 10, R represents a group selected from among alkylenes having 2 or 3 carbon atoms and when n is 2 or more, R may be the same as or different from one another, and M represents an alkali metal selected from lithium, sodium and potassium, and satisfying the following formulae (2) and (3): (2) 0.25 </= x </= 100 (meq/kg) (3) 2 </= (x/[CEG]) x 100 </= 150 (%) wherein x represents the amount of the aromatic sulfonic acid compound represented by the above general formula (1) introduced thereinto and [CEG] represents the amount of the carboxy end groups, and x and [CEG] are each expressed in milliequivalent (meq/kg) per kilogram of the polymer. In a method of manufacturing the modified polyester, the said components (A), (B) and (C) are reacted together in the presence of a catalyst, component (C) preferably being added before before completion of esterification or transesterification of said acid and diol components (A) and (B). |
