| abstract |
The invention relates to a process for preparing a high-molecular polycondensate, i.e. a polyester, a polyamide, a polyester-amide, a polycarbonate, a polyether or a block copolymer by melt-mixing a polyester, a polyamide, a polycarbonate, a polyether or a mixture of at least two of these said polycondensates with a carbonyl bislactam according to formula (I) in which formula n is an integer of between 3 and 15, and a diepoxide. Preferably said diepoxide is a compound containing epoxy radicals of formula (II), which radicals are linked direct to carbon, oxygen, nitrogen or sulfur atoms, wherein R1 and R3 are both hydrogen, R2 is hydrogen or methyl, and m=0, or wherein R1 and R3, taken together, are - CH2-CH2- or -CH2-CH2-CH2-, in which case R2 is hydrogen and m=0 or 1. The present invention results in a more stable process for the production of a polycondensate with a high molecular mass. Furthermore the polycondensate obtained with the process according to the invention has, even under extreme process conditions such as high temperature, less discoloration. With the process according to the invention a permanent increase in the molecular weight of a polycondensate is obtained in an even faster way than with processes according to the state of the art. |