| 摘要 |
PROBLEM TO BE SOLVED: To provide a polyester composition which excels in moldability, heat resistance, and transparency and is particularly suited in the optical application, and a film. SOLUTION: The polyester composition comprises 0.05-5 wt.% composite oxide particles which contain at least one element to be selected from the group consisting of Ca, Zn, Sb, Zr, B, Na, K, Li, and F and have an average particle diameter of 0.3-5μm, a refractive index of 1.47-1.6, a pH of its 5 wt.% aqueous dispersion of >=8 and, simultaneously, a composition meeting three formulae of formula (1): 26 <= amount of Si element <= 37 (wt.%), formula (2): 0 <= amount of Al element <= 13 (wt.%), and formula (3): 32 <= amount of Si element + amount of Al element <= 40 (wt.%), and a polyester in which >=90 mol% the constituting units are ethylene terephthalate units or ethylene naphthalate units.
|
