| 摘要 |
The present invention relates to a process for increasing the molecular weight of polyesters via heating, to from 160 to 350° C., in an extruder, of 100 parts of polyester with i) from 0.01 to 5 parts of a tetracarboxylic dianhydride and ii) from 0.01 to 5 parts of a copolymer which contains epoxy groups and which is based on styrene, acrylate, and/or methacrylate. |
