Preparation process of high molecular weight polyesters.

摘要

The object is to prepare a high-molecular-weight polyester in such a way that it is possible to make even relatively small amounts of very high molecular weight available in an advantageous manner. This is achieved by preparing a polyester containing an alkenediol by continuing the polycondensation step to a viscosity number of 50 - 140 cm<3>/g and treating the resultant polyester with from 0.001 to 8 % by weight of a free-radical former which decomposes at temperatures in the range from 130 to 350 @C with a half value period of from 5 s to 120 min, and subsequently continuing the polymerisation to the requisite viscosity number. The process according to the invention allows high-molecular-weight polyesters having the desired property profile to be obtained.