| 摘要 |
DC-0223 A process for producing a polyamide with a relative viscosity of at least 100 is dislosed. The process comprises adding a catalyst selected from the group consisting of ortho-phosphoric acid, meta-phosphoric acid, alkali-metal hypophosphite and phenylphosphinic acid to the polyamide, which has a relative viscosity of from 30 to 70, mixing the catalyst and polyamide at a temperature above the melting temperature of the polyamide under reduced pressure and for a time sufficient to increase the relative viscosity of the polyamide to at least 100, and extruding the resulting polyamide into shaped form and quenching said polyamide. The catalyst is present in amounts of at least 0.01 wt.% and increases in relative viscosity may develop in times as short as about one minute. |
