| 摘要 |
PROBLEM TO BE SOLVED: To provide a titanium dioxide-containing polyester composition which has good dispersibility and decreases metal wearability, obtained by adding certain amounts of the titanium dioxide which have specified average particle diameters and are certain amounts or below of coarse particles of each specified diameter, certain P2 O5 and K2 O contents, certain ignition loss ratios, certain crystalline particle size and no Fe contents. SOLUTION: A polyester composition contains titanium dioxide of 5.0-70.0 wt.% on the basis of the total weight of the composition, said titanium dioxide being conducted prescribed surface treatment to control its solid state properties. The titanium dioxide is satisfied with each factor that an average particle diameter is 0.1-0.5μm, coarse particles of at least 3μm of a particle diameter are 15,000 number/mg or below, coarse particles of at least 4μm of a particle diameter are 7,500 number/mg or below, P2 O5 is contained by 0.4-0.6 wt.% on the basis of total weight of titanium dioxide, K2 O is contained by 0.1-0.3 wt.% ignition loss ratios are by 0.4 wt.% or below, the values that the weight of rutile type, crystalline state is divided by that of anatase type are by 9×10<-3> or below, crystalline size is 10-150 nm and Fe is substantially not contained.
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