Patent ID: 9011739
Filing Date: 2015-04-21
Classification: D01F,D02J

Abstract:
1. A method comprising: reacting a diamine and a dianhydride in a solvent to obtain a polyamic acid solution; filtering the polyamic acid solution; defoaming the filtered polyamic acid solution under vacuum; spinning the defoamed polyamic acid solution to obtain polyamic acid fibers; coagulating polyamic acid fibers in a solvent; drying polyamic acid fibers; treating and stretching the dried polyamic acid fibers in a tubular heating furnace for a period time from about 5 minutes to about 25 minutes at a plurality of temperatures such that polyimide fibers are continuously prepared from the polyamic acid solution, the tubular heating furnace having three furnace segments, the plurality of temperatures comprising a temperature from about 80° C. to about 280° C. in a first furnace segment of the three furnace segments, a temperature from about 200° C. to about 450° C. in a second furnace segment of the three furnace segments, and a temperature from about 400° C. to about 550° C. in a third furnace segment of the three furnace segments; and winding polyimide fibers to obtain rolls of polyimide fibers.