| abstract |
The preparation from a solution of the polyimides of the general formula in aprotic organic solvents is carried out using the dry spinning method.n n n In order to obtain fibers with improved usage properties according to the dry spinning method, which, with the same basis weight as fibers of round cross-section, guarantee much better coverage, a pleasant grip and a high gloss, fibers with an irregularly lobed or serrated cross-section are used, wool-like, soft Handle and high gloss of the dry spinning process carried out in a spinning shaft, wherein a 20 to 40% solution of the polyimide is spun from nozzles with a round cross-section, number of holes from 20 to 800 and a nozzle hole diameter from 100 to 300 microns, a spraying speed between 20 and 100 m / min, a take-off speed between 100 and 800 m / min, a spinning gas quantity between 40 and 100 m 3 / h, based on normal conditions and a spinning gas temperature between 200 and 350 ° C, the shaft cables obtained with a residual solvent content of 5 to 25 % By weight - based on the polymer solid - and with a single filament titer between 3.5 and 35 dtex washed in hot water, then dried to a moisture content of less than 5%, then stretched at high temperature and optionally crimped and cut into staple fibers. |