| 摘要 |
PURPOSE:A composition having extremely improved fastness to light when it is used especially as white fluorescent dye, obtained by adding a cobalt compound and a phosphorus compound to a PBT polyester synthesized with a specific catalyst, having specified intrinsic viscosity. CONSTITUTION:A polyester having >=80wt% constitutional unit of polyester consisting of butylene terephthalate residue is blended with 5-50ppm calculated as cobalt atom of a cobalt (Co) compound, and 5-50ppm calculated as phosphorus atom of a phosphorus compound. The polyester is obtained by using a titanium (Ti) compound as a catalyst for synthesis, and contains an alkali (alkaline earth) metal in an amount shown by the formula, 0.1<=M/Ti<=0.7 (T and Ti are chemical equivalent of the alkali metal and titanium contained in the compound, respectively), Ti=15-150ppm, to improve extremely fastness to light. The polyester has 0.5-1.0 intrinsic viscosity [eta].
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