| 摘要 |
PURPOSE: A polyethylene terephthalate copolymer excellent in velocity of crystallization is provided, which improves the problem of separation to the outside at a high temperature and has a surface-improving effect. And a process is also provided to produce the polyethylene terephthalate copolymer. CONSTITUTION: The polyethylene terephthalate copolymer is produced by the process comprising the steps of: transesterifying dimethyl terephthalate or terephthalic acid and ethylene glycol with a metal catalyst at 130-230deg.C; adding 0.5-30pts.wt.(based on the dimethyl terephthalate or the terephthalic acid of 100pts.wt.) of a dimerized fatty acid(formula 1) to perform an additional esterification; polycondensing the resultant under a high temperature and high vacuum. The polyethylene terephthalate copolymer has a glass transition temperature of 20deg.C or higher and a crystallization range of 100-160deg.C. In the formula, X is a linear, aliphatic ring, or aromatic ring type hydrocarbon group and R1, R2, R3, and R4 are C5-C10 alkyl groups or alkylene groups or C5-C10 alkyl groups or alkylene groups of which the terminals are substituted by -COOH, wherein the total maximum carbon number of R1, R2, R3, and R4 is 16-52 and at least one of R1, R2, R3, and R4 has -COOH on the terminal.
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