| 摘要 |
<p>A copolyester is prepared from bis(betahydroxyethyl) terephalate (for preparations see Group IV(b)) and 2,2-bis(4-(beta-hydroxyethoxy) phenyl] propane by charging a molten mixture through a funnel fitted with a screen into a roundbottomed cylindrical reactor filled with nitrogen and equipped with a stirrer. Ethylene glycol titanate, prepared by adding ethylene glycol to a solution of tetraisopropyl titanate in benzene, allowing to stand for 24 hours and then filtering off and drying the precipitate, is placed in the funnel beneath the screen so that it will be carried into the reactor by the molten charge. The temperature is raised and pressure reduced slowly to 275-280 DEG C. and 0,5 mm. Hg respectively in 1,5 hours. The polymer is discharged from the reactor when its reaches an intrinsic viscosity of 0,65 to 0,70. Specification 766,290 is referred to.ALSO:Bis (beta-hydroxyethyl) terephthalate is prepared by charging a molten mixture of dimethyl terephthalate and ethylene glycol into a flask equipped with a heating mantle, fractionating column, nitrogen inlet tube and stirrer. Ester interchange catalysts (zinc acetate and manganese acetate) are added at a temperature of 140 DEG C. The temperature is slowly raised, while sweeping out the methanol evolved in a slow stream of nitrogen. The column is cooled with compressed air to maintain its top below 70 DEG C. The reaction is complete after 45 minutes at 200 DEG C. Specification 766,290 is referred to.</p> |
