| 摘要 |
<p>Ribbon filaments of regenerated cellulose are made by extruding viscose having a cellulose to caustic soda ratio of at least 1 and at a salt point of 4-6 through a multihole jet, the holes of which have no re-entrant sector in their cross-sections, into a coagulating bath held at 40 DEG -60 DEG C. and containing at least 24% Na2SO4, 9-12% H2SO4 and not more than 0,02% ZnSO4 as an impurity, drawing the incompletely regenerated filaments from the bath and subsequently completely regenerating the filaments. Preferably the jet holes are of circular cross-section. The cellulose to caustic soda ratio of the viscose may be at least 1,4 with a salt point of 4-6, or may be between 1 and 1,25, when the salt point is desirably 4-4,5. In an example a viscose is extruded through holes of 0,005 inch diameter and the filaments pass through the bath for 24 inches before being lapped on a godet. They are then stretched 30% in passing to a second godet of higher peripheral speed, collected in a centrifugal box and the cake washed successively with dilute acid and water. Such filaments have an elongated cross-section, their width being in general five times their thickness.</p> |
