| 摘要 |
PROBLEM TO BE SOLVED: To obtain a polyester resin having a good weathering property and a high degree of polymerization. SOLUTION: A required amount of a monomer (for example, terephthalic acid and ethylene glycol) and a catalyst (for example, tetra-butyltitanate) are fed into an autoclave, and an esterification reaction is carried out at 160-230 deg.C under pressurized condition, to be finished (the rate of esterification: 100%). After distillating out of produced water, a required amount of a bisbenzotriazolephenol-based ultraviolet-ray absorbing agent such as 2,2- methyl[6-(2H-benzotriazol-2-yl)-4-(2-hydroxyethyl)phenol], is added in the reaction system, and after stirring at about 25 deg.C for a required time, the reaction system is gradually reduced in pressure, and a polycondensation reaction is carried out at about 260 deg.C in a vacuum state of 0.3 mmHg or below.
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