The process of the present invention for producing a polyester resin comprising a dicarboxylic acid constitutional unit and a diol constitutional unit having a cyclic acetal skeleton comprises a step (1) of subjecting a diol (A) having a cyclic acetal skeleton and an ester (D) to transesterification reaction and a step (2) of mainly converting the resultant oligomer into a high polymer. The step (1) simultaneously satisfies the requirements (i) to (iv) as described in the specification. In the process of the present invention, the polyester resins having excellent moldability and mechanical properties are stably produced by a transesterification method which is less detrimental to environments.
本发明生产聚酯
树脂的工艺包括二
羧酸结构单元和具有环
缩醛骨架的二元醇结构单元,其步骤(1)是将具有环
缩醛骨架的二元醇(A)和酯(D)进行酯交换反应,步骤(2)主要是将生成的低聚物转化为高聚物。步骤(1)同时满足说明书中描述的要求(i)至(iv)。在本发明的工艺中,通过对环境危害较小的酯交换反应方法,可以稳定地生产出具有优良成型性和机械性能的聚酯
树脂。