METHOD FOR SOLID PHASE POLYMERIZATION

摘要

An improved method for increasing the relative viscosity and molecular weight of a polyamide polymer (such as nylon 6,6, nylon 6, and the like) while in the solid state involving the use of a phosphorus-containing catalyst (such as 2(2'-pyrydyl)ethyl phosphonic acid, sodium hypophosphite, tolyl phosphinate and manganese hypophosphite or the like) in combination with an oxygen free gas characterized by a low dew point (typically below 30 .degree.C and preferably below -30 .degree.C). Operational and commercial advantages are derived from the combination of using simultaneously a phosphorus-containing catalyst and the recycle of very low dew point drying gas at lower operating temperatures than previously employed in conducting solid phase polymerization of polyamide polymer. Such a process is of particular value during the production of terpolyamide and multipolyamide polymer intended for use in colored nylon fiber manufacture.